Abstract
Background
Scabies is the second most common cause of disability among skin diseases in the Philippines as of 2019. There is no large nationwide study describing the epidemiologic profile of scabies in the country.
Objective
This study aimed to describe the demographic, seasonal, and geographic profile of scabies in the Philippines.
Methods
We compared secondary data of two local patient registries (Philippine Dermatological Society, PDS, 2010 to 2021; and Philippine Pediatric Society, PPS, 2009 to 2021) for reported cases of scabies in the Philippines. We reported the frequency and percentage distribution according to age, sex, month, year, and type of diagnosis, and region.
Results
The median annual frequency of scabies cases (mostly outpatient) for PDS (from year 2010) was 4087 (range ([QR], 342-6422 [3271.5]), while it was 183 (range [IQR], 64-234 [96.5]) (all inpatient) for PPS (from year 2009). There was a reduction to one-third (PDS) and one-fourth (PPS) of pre-pandemic numbers during the pandemic years (2020-2021). The peak months for scabies cases were the cooler months: January (median, 12.1% of annual cases; range [IQR], 2.6%-31.4% [3.6%]) to February (median, 10.0% of annual cases; range [IQR], 1.5%-27.8% [2.5%]) based on PDS data, and November (median, 10.0% of annual cases; range [IQR], 0.0%-24.3% [7.0%]) to January (median, 9.0% of annual cases; range [IQR], 0.0%-24.3% [6.6%]) for PPS data. Overall, for PDS, age 1-4 years is the most affected age group (median, PDS, 17.5% of annual cases; range [IQR], 11.9%-25.4% [8.1%]), while it was the less than 1-year-olds (median annual cases, 48.9%; range [IQR], 29.1%-67.3% [13.20%]) among PPS pediatric population aged 0 to 18 years. Males (median, 53.9% of annual cases; range [IQR], 45.0%-67.2% [8.8%]) were more affected than females in PPS. While for PDS during earlier years (prior to 2015), males (median, 51.6% of annual cases from 2010 to 2014; range [IQR], 47.4%-52.9% [0.2%]) were more affected than females. However, males became less affected than females with median, 44.7% of annual cases from 2015 onwards (range [IQR], 43.4%-46.5% [1.2%]). NCR was the region with the highest frequency of cases in PPS (median, 52.6% of annual cases; range [IQR], 22.7%-75.0% [20.4%]). The 2nd most affected regions were Central/Eastern Visayas (34.2%, 2009-2013; range [IQR], 17.9%-54.1% [5.3%]), Bicol region (12%; 2014 to 2018; range [IQR], 17.9%-54.1% [7.4%]), Central Luzon (18%; 2019), Central/Eastern Visayas (29%, 2020), and Northern/Central Mindanao (17%, 2021).
Conclusion
Scabies was commonly seen in the younger age group, slightly more in females in the PDS, while slightly more among males in the PPS, in the cooler months of the year, and in the urbanized NCR.
Keywords: scabies, Philippines, epidemiology, database, registry, secondary data
INTRODUCTION
Scabies is an ectoparasitic skin infestation that remains to be a highly prevalent infectious skin disease mainly in tropical countries. Scabies has been a public health problem in the Philippines as early as a 1918 census and a World War II US army personnel report.1,2 In a World Health Organization (WHO) Regional seminar on tropical skin diseases in 1975, a ‘scabies alert’ was reported due to an ongoing epidemic in the Philippines and Hong Kong.3 In 1975, a published review of reported cases in the Greater Manila Area (Philippine General Hospital, University of Santo Tomas Hospital Dispensary, private practice of Dr. FC Bocobo) showed that parasitic skin diseases ranked 4th or 5th among all dermatological cases.4 A national prevalence survey of fungal and other skin diseases in 24 cluster sites throughout the Philippines (N=9259) published in 1999 showed scabies to be the 2nd most common dermatologic problem (prevalence 27.5/1000), next to arthropod bite reaction (30.7/1000).5 In a community survey of households and individuals (N=5121) in six leprosy-endemic areas in in the Philippines from 1999-2000, infestations and insect bites accounted for the 2nd highest percentage (9.0%) of skin diseases in the communities, second only to superficial mycoses (18%); scabies accounted for 2.01%.6 In both latter surveys, underreporting was noted since some participants refused to show certain skin areas. More recently, jail outbreaks have been reported in the news with the use of benzyl benzoate lotion reported as successful in eradicating scabies among inmates.7,8
The age group profile as of 2015 showed the biggest percentage from the 5-14 y/o (21%) and 15-24 y/o (20%) groups.9 The Philippines has an estimated mid-year population of 109M (as of May 1, 2020, based from 2020 national census of population with estimated 1.63% growth rate from 2015 to 2020).10 The Philippines has three big islands, Luzon (109,965 km2), Mindanao (97,530 km2), and Samar (13,429 km2). The country has 17 administrative regions, 33 highly urbanized cities (HUCs), 108 component cities, five independent component cities, and 1,488 municipalities. The average population density of the country is 363 persons per square kilometer of land (as of 2020), with NCR as the most densely populated (21,765 persons per sq km), which is almost 60 times the average national level. Of the 33 HUCs in the country, half (16) were in the NCR. The Philippines has a tropical and maritime climate characterized by relatively high temperature (average 26.6°C, excluding Baguio City), high humidity (range, 71 to 85%) and abundant rainfall (annual, range 965 to 4,064 mm).11 There are two major seasons in the country (based on temperature and rainfall): (1) the rainy season, from June to November; and (2) the dry season, from December to May. The dry season may be subdivided further into (a) the cool dry season, from December to February; and (b) the hot dry season, from March to May.
The top two most common diseases in the Philippines are infectious (acute respiratory infection, pneumonia) followed by hypertension.9 Scabies is not a notifiable disease in the Philippines. In the 2020 Guidelines for Mandatory Reporting of Notifiable Diseases and Health Events of Public Health Concern Act, only hand, foot, and mouth disease, transmissible through direct skin contact, is identified as a priority disease for surveillance.12
The Philippines is ranked 9th among 195 countries worldwide in the disability-adjusted life years (DALYs) contributed by scabies based on Global Burden of Disease (GBD 2017).13 Among the skin diseases in the Philippines, scabies constitutes the 2nd highest DALYs based on the latest GBD 2019.14
The public health control of scabies needs a 3-pronged approach: mapping of disease burden, delivery of interventions, and establishing monitoring and evaluation, as recommended in a framework drafted by an expert panel convened by the WHO in 2019.15,16 As a first step to achieving the goals of the WHO Roadmap for NTDs aimed at ending the neglect to attain the sustainable development goals by 2030,17 it is important to describe the epidemiology of scabies in the Philippines. This study aimed to determine the demographic, seasonal, and geographic profile of scabies through secondary analysis of local patient registries.
METHODS
This retrospective registry-based study was conducted from September 15 to December 15, 2022. It is part of the review of literature for a bigger research project (PhD dissertation of principal investigator), the protocol of which was submitted and approved by the University of the Philippines Research Ethics Board (UPM REB-2022-0055-01). The protocol for this substudy may be requested from the author. For this manuscript, we will describe only two patient registries that are managed by their respective specialty medical societies in the Philippines. We compared the trends in the two patient registries considering that they differ in case definition, patient population, setting, and geographic distribution. We did not pool them due to these differences. Succeeding publications will present data from government patient registries and surveillance data, as well as a systematic review of epidemiologic studies from the literature.
We extracted data from the following patient registries:
Philippine Dermatological Society Health Information System (PDS-HIS) (2010 to present)
The database was conceptualized in 2005 and includes data from most of the accredited training institutions beginning from 2010. The Philippine Dermatological Society (PDS) is the officially accredited specialty society for dermatology by the Philippine Medical Association (PMA) and currently has 1327 members in all 17 regions of the Philippines, majority of whom are in the NCR (754, 56.82%), and with only one member in ARMM (personal communication, PDS Secretariat). The PDS members consists of graduates of residency training or mentorship from 13 training institutions (11 in the NCR, 1 in Region 1, and 1 in Region XI) (www.pds.org.ph, as of December 21, 2022). To the original 11 institutions, one institution in NCR in 2021 and one institution in Region 1 in 2022, were added. Although the PDS has four regional chapters (Southern Philippines, Northern Luzon, Southern Luzon, Central Luzon) as of 2022, these chapters are composed of private dermatologist members of PDS who do not contribute data to the PDS-HIS.
The PDS-HIS registry was created for purposes of research, lectures/reports, publications, public health reporting, health information and advocacy, healthcare operations, benchmarking, and quality monitoring. It contains the demographic profile (age, sex) and diagnosis of patients seen at the dermatology departments of the different training institutions for either outpatient, inpatient, emergency room, and inpatient referrals. Majority of cases are outpatient (99.5%) (personal communication, PDS-HIS committee). The PDS-HIS is searchable upon request from and submission of documentary requirements to the PDS-HIS committee. The data in the PDS-HIS is encoded by dermatology resident physicians of the PDS training institutions on cases seen in the following patient areas – emergency room, inpatient, outpatient, and is managed by a task force (members of PDS) together with an informatics consultant and systems administrator. The DermLex Version 1.0 (American Academy of Dermatology; DermLex: The Dermatology Lexicon) is a standardized terminology of dermatologic diagnoses, therapies, procedures, and laboratory tests that PDS-HIS recommends its encoders to use. In the earlier versions, however, the diagnoses were encoded free hand with no specific dropdown choices; recently, there are dropdown choices although encoder may still choose to enter a freehand diagnosis.18 In 2010, only one institution (Philippine General Hospital, PGH) encoded data into the PDS-HIS as a test run. From 2011 to 2016, the 11 PDS-accredited institutions were all encoding data. Due to data privacy issues, in 2017, three institutions only partially encoded data, and in 2018, temporarily stopped encoding. A total of six institutions did not encode in 2019 until 2020 when only six institutions encoded data. By 2021, 10/12 institutions, and by 2022, 12/13 institutions were encoding data. We only included ‘new cases’ and excluded ‘follow-up cases’ (follow-up case defined as - if the patient was already diagnosed in a previous visit and just followed up, with the follow-up visit being not necessarily within the same year) to avoid double-counting the same case. Data collection in the PDS-HIS database was done through Excel files provided by PDS-HIS.
Philippine Pediatric Society (PPS) Registry of Childhood Diseases (2006 to present)
This registry has been maintained by the Philippine Pediatric Society since May 2006. It serves as a repository of monthly hospital ward discharges from the Philippine Pediatric Society Hospital Accredited Board (PPS-HAB) hospitals for children up to 18 y/o. The registry is searchable by ICD-10 code (diagnosis), age, sex, month/year, outcome, and region/hospital. By typing in the ICD code of the disease and selecting the desired filter, the number of cases over the total number of cases will be shown. The ICD-10 code for scabies is B86 and was used to encode the case into the registry. Scabies is defined as “A contagious cutaneous inflammation caused by the bite of the mite Sarcoptes scabiei. It is characterized by pruritic papular eruptions and burrows and affects primarily the axillae, elbows, wrists, and genitalia, although it can spread to cover the entire body.”19 The category of tertiary diagnosis (versus primary and secondary) was only added to the data collection form in 2019 to record chronic conditions. The Philippine Pediatric Society has 6,581 members (as of September, 2021) with members spread all over the country.20 There are currently 12 PPS chapters representing all 17 regions of the country. A total of 117 hospitals contribute to the registry (NCR chapter, 55 hospitals; Northern Luzon chapter, 5 hospitals; Northeastern Luzon chapter, 3 hospitals; Central Luzon chapter, 9 hospitals; Southern Tagalog chapter, 6 hospitals; Bicol chapter, 2 hospitals; Negros Occidental/Western Visayas chapter, 9 hospitals; Cebu Eastern/Central Visayas, 16 hospitals; Northern/Central Mindanao chapter, 5 hospitals; Davao/Southern Mindanao chapter, 7 hospitals;) contribute data to the registry.21 The number of hospitals contributing data varies per month and ranged from 88 to 108 (from 2009 to 2021) (personal communication, Dr. Edilberto Garcia, Jr.). The registry is publicly accessible and searchable through the portal at https://pps.ivant.com/search.do. The PPS registry portal was manually searched to collect data in an Excel file, and was validated by the PPS registry head.
We extracted the number of scabies cases over the total number of cases (various diagnoses) seen. We then computed for the median (IQR) frequency and percentage of scabies cases per year for the two patient registries and compared them across month, year, age group, sex, type of diagnosis, outcome, region, depending on data availability. We used Microsoft Excel to compute for the frequency, percentages, medians, and ranges, while we used Stata Version 17.0 (Stata Corp)22 to generate graphs showing the frequency or percentage distributions.
RESULTS
Overall, scabies cases accounted for 5.15% median annual percentage (range [IQR], 2.97%-8.81% [2.35%]) of all outpatient and inpatient cases of skin disease in PDS from 2010 to 2021, while it accounted for median 0.05% (range [IQR], 0.02%-0.11% [0.02%]) of all inpatients in PPS-accredited hospitals.
For PDS, the median annual frequency of cases was 4087 from 2010 to 2021, with a notable decrease by one fourth from pre-pandemic (2010-2019) (4227 cases) to pandemic years (2020-2021) (1124 cases) (Table 1). There was also a declining number of cases even prior to the pandemic from peaking in 2014 (6422 cases), going down in 2021 to 1207 cases. It was noted that beginning in 2018, not all member institutions were able to contribute data due to changes in institutional policy regarding data privacy. An abrupt decrease in the number of cases were noted from March 2020 (red line), coinciding with the start of lock-downs due to the COVID-19 pandemic (Figure 1A).
Table 1.
Estimated Annual Frequency and Percentage Distribution of Scabies Cases in PDS (2010-2021) and PPS (2009-2021)
| Year | PDS | PPS | ||||
|---|---|---|---|---|---|---|
| Number of cases with scabies | Total number of cases seen | Percentage with scabies | Number of cases with scabies | Total number of cases seen | Percentage with scabies | |
| 2009 | – | – | – | 220 | 205784 | 0.11% |
| 2010 | 342 | 9687 | 3.53% | 234 | 336802 | 0.07% |
| 2011 | 2366 | 68462 | 3.46% | 229 | 330610 | 0.07% |
| 2012 | 5340 | 78510 | 6.80% | 152 | 323821 | 0.05% |
| 2013 | 5371 | 60970 | 8.81% | 151 | 342828 | 0.04% |
| 2014 | 6422 | 83586 | 7.68% | 227 | 364980 | 0.06% |
| 2015 | 5780 | 92625 | 6.24% | 183 | 338127 | 0.05% |
| 2016 | 4327 | 91814 | 4.71% | 187 | 380031 | 0.05% |
| 2017 | 4127 | 93158 | 4.43% | 131 | 414636 | 0.03% |
| 2018 | 4046 | 72506 | 5.58% | 230 | 403120 | 0.06% |
| 2019 | 3294 | 54850 | 6.01% | 100 | 446296 | 0.02% |
| 2020 | 1040 | 24782 | 4.20% | 66 | 180863 | 0.04% |
| 2021 | 1207 | 40623 | 2.97% | 64 | 115312 | 0.06% |
Note: In bold font are peak number for each registry; PDS registry only started in 2010 with just one institution as a test run.
PDS, Philippine Dermatological Society; PPS, Philippine Pediatric Society
Figure 1.
Annual time series of cases with scabies from 2009 to 2021. (A) Philippine Dermatological Society (PDS), (B) Philippine Pediatric Society (PPS).
In comparison, data from the PPS Registry (2009 to 2021) showed a median annual frequency of hospitalized cases of scabies at 183. The annual number of cases peaked in 2014 (was stable pre-pandemic (2010-2019) with a median annual frequency of 187 cases, while it was reduced to about one-third (65 cases) of pre-pandemic numbers during the pandemic (2020-2021) (Table 1). There was a nadir in the number of cases after the start of lockdowns (red line, March 2020) due to the COVID-19 pandemic (Figure 1B).
There is an observed seasonal nadir of cases around June of the year for both PDS (237 cases) (Figure 2A; Appendix Table A1) and PPS (6 cases) (Figure 2B; Appendix Table A2) data. The peak however was different: in January (479 cases) for PDS and November (20 cases) in PPS database, although both peaks represent the cooler months of the year.
Figure 2.
Cycle plot of distribution of patients with scabies from 2009 to 2021. (A) Philippine Dermatological Society (PDS), (B) Philippine Pediatric Society (PPS).
In the PDS registry, during the pre-pandemic period from 2010 to 2019, the 1 to 4 y/o age group had the highest median annual percentage of cases (18.9%; range [IQR], 12.7%-25.4% [6.3%]). From 2020 to 2021, the highest percentage of cases were in the 19 to 24 y/o (16.1% in 2020; 14.6% in 2021). Comparing among the patients included in the PPS registry, it has been consistent across the years that the highest number of cases were among infants (<1 y/o.) (median, 48.9%; range [IQR], 29.1%-67.3% [13.20%]), followed by toddlers (1-4 y/o.) (median, 27.2%; range [IQR], 9.0%-45.2% [4.20%]), except for the year 2018 where there were more cases seen among toddlers than infants (Appendix Table A3). Higher proportion of cases seen in infants in the PPS registry compared to PDS data may be due to the idea that infants are more likely to be brought to pediatricians for consultation even for skin conditions rather than to dermatologists.
From 2010 to 2016, there were 380 more cases of scabies infestation per year in the pediatric age group in the PDS data. However, beginning in 2017, as the trend shifted with a higher proportion of cases seen among adults, there were 223 more cases per year. Across all the years, the age group 1-4 y/o has the highest median of annual cases (17.5%; range [IQR], 11.9%-25.4% [8.1%]), followed by 5-9 y/o with 12.6% (range [IQR], 10.7%-14.2% [1.9%]). Among adults, the most affected age group is 19-24 y/o with 22.2% (range [IQR], 14.5%-26.7% [2.6%]; and median 10.2% overall; range [IQR], 7.3%-16/1% [2.1%]), followed by 25-29 y/o with 13.6% (range [IQR], 6.7%-18.2% [2.4%]; and median 6.3% overall; range [IQR], 3.4%-10.8% [1.7%]). Toddlers (1-4 y/o), have the highest median of 34.6% among all pediatric patients (range [IQR], 28.3%-44.9% [5.3%]).
It is to be noted that although number of scabies was decreased overall, there was a relative increase in the percentage distribution in the 19 to 44 y/o age group in PDS, from 2019 (1161/3260, 35.6%), the year right before the pandemic, to 2020 (426/1015, 42.0%) by 17.8% (Appendix Table A4).
In the PDS data, there were slightly fewer cases of scabies among males (20,351 males vs 22125 females; median M/F ratio, 0.9 (range [IQR], 0.8-1.1 [0.3]). However, from 2010-2014, there were slightly more cases among males (median M/F ratio, 1.1; range [IQR], 0.9-1.1 [0.1]) before switching to a higher number among females in 2015 and beyond (Appendix Table A5). In the PPS registry, there were generally more cases among males (1212 males vs 962 females; median M/F ratio, 1.2; range [IQR], 0.8-2.0 [0.5]), except in 2019 (M/F ratio, 0.8) (Appendix Table A5).
Most cases of scabies in the PPS registry were reported in Luzon, particularly in the National Capital Region, with a median percentage of 52.6% of annual cases; (range [IQR], 22.7%-75.0% [20.4%]) (Figure 3). From 2009 to 2013, the region with second highest number of cases were from Central/Eastern Visayas (34.2%; range [IQR], 17.9%-54.1% [5.3%]), followed by Bicol region (12.0%; range [IQR], 6.6%-29.8% [7.4%]) from 2014 to 2018. In 2019, the second-highest number of cases were in Central Luzon (18.0%); followed by Central/Eastern Visayas (28.9%) in 2020; and Northern/Central Mindanao (17.2%) in 2021. Almost all reporting institutions in the PDS, 10/11 from 2010 to 2019, and 11/13 thereafter, are based in the NCR, and are likely to represent patients in this region.
Figure 3.
Annual distribution of patients with scabies as to region/Philippine Pediatric Society (PPS) chapter.
Note: PPS chapters cover all 17 regions in the Philippines; each chapter may cover more than one political region. Northern Luzon – Region I and CAR; Northeastern Luzon – Region II and proximal areas of Ifugao and Kalinga-Apayao; Central Luzon – Region III; National Capital Region; Southern Tagalog – Region IV; Bicol – Region V; Western Visayas – Region VI; Central/Eastern Visayas – Regions VII and VIII; Northern/Central Mindanao – Regions IX, X, and XIII; Southern Mindanao – Regions XI, XII, BARMM, and parts of Zamboanga.
The percentage of scabies reported as the primary diagnosis (median, 43%; range [IQR], 40%-46% [4%]) in the PPS registry was initially lower than those reported as the secondary diagnosis from 2009 to 2016 (median, 49%; range [IQR], 54%-60% [4%]). However, it became slightly greater than those reported as secondary diagnosis from 2017 to 2020 (mean, 52%; range [IQR], 51%-68% [5%]). The category of tertiary diagnosis was only introduced in 2019 to account for chronic diseases, and there were three such cases in 2019, and 18 in 2021, which made up a third of the annual cases (Appendix Table A6).
Fourteen deaths among pediatric patients with scabies were reported in the PPS registry, with three deaths in 2011, three in 2012, and eight in 2018. No time-series trends were identified, and the cause of death may not be due to scabies, as it was not specified in the registry.
DISCUSSION
The median annual percentage of registry-reported scabies cases in the past decade ranged from 5.99% in outpatient and inpatient cases in all age groups (PDS) to 0.05% among inpatient pediatric cases (PPS). Cases were more frequent in cooler months and decreased significantly during the pandemic (2020-2021). The 19- to 44-year-old age group had a relative increase in percentage of cases (17.8%) during the pandemic in the PDS. Toddlers (1-4 y/o) were most affected in PDS and infants aged 28 days to 1 year in PPS. Males were slightly more affected than females in PPS and before 2015 in PDS. The NCR was the region with the highest frequency of cases in PPS, while majority of the reporting institutions to the PDS were from the NCR.
The higher percentage of cases in the PDS registry (5.99%) is explained by the inclusion of outpatient cases in this population. On the other hand, the low percentage among inpatient pediatric cases (0.05%) reflect the low hospitalization rate of scabies, as it is mostly managed in the outpatient setting. A more thorough investigation would need to conduct a survey among private clinics of dermatologists, especially those outside the NCR. In addition, the outpatient census of the pediatricians from PPS can also be surveyed to determine the percentage of scabies cases. Further exploration of the impact of this missing data may involve extrapolation of data and statistical modelling, and can be recommended for future studies.
The decrease in scabies cases in both PDS and PPS registries during the pandemic contrasts with studies in Europe. Although there was an overall decrease in the dermatologic consultations during the COVID-19 pandemic in several countries due to the lockdown policy, there was a general trend towards increased proportion of scabies cases. An increase in the proportion of scabies cases was observed in Turkey; in a dermatology outpatient clinic (N=376, from 1st to 30th April 2021) (10/9%) compared to previous years (2.8%, 2006 to 2017), based on Ministry of Health data,23 and a tertiary medical center (N= 36,469).24,25 There was also a fourfold increase in incidence of scabies in a representative national primary care database in Netherlands from 2011 (0.6 per 1000) to 2020 (2.6 per 1000).26 This involved adolescents and young adults (15 to 29 y/o), which was hypothesized to be increased sexual intercourse due to increased sleepovers and confinement to homes from lockdown policies. Similarly in the UK, there was an increase in the prescription of oral ivermectin for difficult-to-treat scabies during March 2020 to July 2021 thought to be due to sharing spaces and working from home.27 In our study, we also found an increase from prepandemic (2019) to pandemic (2020) years by 17.8% in the 19 to 44 y/o age group compared to the rest of the age groups (range, -33.1 to 1.2%). It is noted that this age group had increased mobility and potential in-person interaction as the Philippine government only allowed 21 to 59 y/o to leave their homes in March 2020.28
Seasonal distribution in our study follows the trends in other countries where the cooler season and autumn and winter months registered higher number of scabies cases such as South Korea,29 Taiwan,30 Iran,31 and Israel.32 A recent review of epidemiological studies on scabies from 2020-2022 comparing Europe with the rest of the world showed seasonality as contributing to the high incidence during the autumn and winter months.33 A positive correlation with relative humidity and negative correlation with temperature was found in two population-based studies in Taiwan (14-year)30 and northeast Poland (8-year).34 Scabies mites were shown to have better survival with higher relative humidity and lower temperatures in an in vitro study.35
The low number of deaths in cases with scabies is noted in the PPS database. The GBD 2019 assumes a null mortality from scabies, although this may be an underestimation since it was noted that they did not include life years lost and limited consequences to skin involvement. However, post-streptococcal complications may also lead to deaths from cardiac or renal sequelae. Crusted scabies is associated with significant mortality in a hospital in Australia (30-day mortality rate of 2.5% of all admissions to hospital with severe or crusted scabies).36 The mortality data from PPS did not specify the type of scabies as to classic vs crusted and it is also possible that the death may not be due to scabies but an underlying or accompanying condition. Immunosuppression is a risk factor for crusted and severe scabies. In a prospective cohort of 78 patients with crusted scabies in Australia, identifiable immunosuppressive risk factors were identified in more than half of patients (eosinophilia, elevated IgE, leprosy).37 There are a few case reports on crusted scabies associated with immunosuppressed conditions in the Philippines, one was in 2-year-old healthy infant with miliaria rubra given topical steroid and a 55-year-old with diabetes and hepatitis B.38,39 In both cases, patients recovered from the scabies infestation. It is not possible to speculate on the cause of mortality in the reported cases in the PPS registry.
The highest median annual percentage of cases was seen in the 1 to 4 y/o age group (31%) in the PDS. In the PPS, the highest median annual percentage was among infants 1 month to 1 y/o (49%). This may be explained by the affected children being brought by their parents to pediatricians rather than dermatologists even for skin concerns. In such instances, the adult caregivers may also show symptoms and signs of scabies, but were not tallied anymore as scabies cases, but just as close contacts.
Males having a higher frequency of scabies as shown in the pediatric inpatients seen in the PPS registry is similar to the trend in Cameroonian40 and Indonesian boarding schools,41 and a US dermatology practice.42 This could be attributed to greater transmission among males from the higher physical activity and sweating in contact sports in men and rough play in boys compared to girls. On the other hand, the slightly higher percentage of females with scabies in the PDS registry may be due to the increased likelihood for women and girls to consult a dermatologist due to a skin problem, being more conscious of their appearance than men and boys.
The shift to a lower male:female ratio in 2015 is difficult to explain. There was a slight dip in the percentage of women in the labor force in the Philippines from 39.5% (2015) to 37.9% (2017) and with slow increase to 38.9% (2021), which may have resulted in reduced mobility of women allowing more time spent with their children, thereby possibly facilitating the transmission of scabies.43
The greatest number of cases in NCR based on PPS data in our study is compatible with overcrowding in urban areas as one of drivers of transmission of scabies. The NCR population density, is the most densely populated with 60x that of the national level. The 2nd highest number of cases from 2009 to 2013 was in Eastern Visayas, which is also endemic for soil-transmitted helminthiases (Leyte) and is the top region with poor sanitation.44 The UNICEF has reported that sanitation targets in the Philippines, together with the rest of the world, are off-track from the goal to provide sanitation for all by 2030.45 A recent typhoon in Southern Leyte required concerted efforts to restore access to clean water and sanitation facilities.46 In a systematic review by Roswendi et al., it identified poor environmental sanitation, (lack of clean water, sewerage and garbage disposal), as factor for scabies mites to breed and spread widely.47 In 2021, a joint effort by local prison authority, local government unit, a non-government organization, and the Philippine Dermatological Society to eradicate scabies showed more than half of inmates 396/688 (58%) were diagnosed with clinical or suspected scabies.8
Limitations of this study include potential underreporting for both PDS (since 10/12 contributing institutions are in the NCR) and PPS (only inpatient cases were included). As scabies is also seen in other urban centers and resource-poor communities outside of the NCR, we may be missing these data. Surveillance for scabies in the resource-poor regions outside NCR where there is less healthcare access must be conducted. Rapid mapping in areas of reported outbreaks should be undertaken. Community surveillance must be prioritized over school-based programs since the most affected are the 1-month to 4-year-olds. Since the peaks are in the cooler months of the year, surveillance is best scheduled between November to January. The PDS and PPS can train primary care physicians and community health workers to recognize and treat scabies.
In addition, as scabies is more likely to be seen in the outpatient setting, the pediatric cases in this analysis only represent the hospitalized patients. Private clinic census data of dermatologists and pediatricians may also be surveyed if available to determine the true extent of the burden of disease. Information on outbreaks in communities that are served mostly by rural health centers may also be missed. Thus, there is a need to gather more data from other sources, such as government-run patient registries (e.g., PHIC), DOH epidemiology bureau surveillance data, and LGU reports, and a systematic review of published and unpublished epidemiologic studies. With the looming implementation of the Universal Health Care Act (Republic Act No. 11223), the burden of disease of scabies must be determined for budget planning and resource allocation for its prevention and control. An integrated approach to co-endemic NTDs, which includes scabies, should also be used to maximize resources and minimize cost. Cost effectiveness analysis and budget impact analysis must prioritize the age group between 1 month to 4 y/o where cases are most found.
CONCLUSION
Scabies was commonly seen in the younger age group (<5 y/o), slightly more in females in the PDS, while slightly more among males in the PPS, in the cooler months of the year, and in the urbanized NCR and Central/Eastern Visayas region. Since the PDS and PPS data may not be representative of the national situation, a comprehensive nationwide and community-based, rather than school-based surveillance, should target regions outside the NCR between November and January. There is a need to estimate the burden of disease in the Philippines to guide policy, practice, and future research.
Acknowledgments
The authors are grateful to the PDS-HIS Task Force (Dr. Arunee Siripunvarapon, Chair; Dr. Jose Dumagay, Medical Informatics), and Dr. Edilberto Garcia, Jr, PPS Registry Manager, for their assistance.
APPENDICES
Table A1.
Total Monthly Number of Scabies Cases Recorded in the PDS Registry from January 2010 to December 2021
| Month | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| January | 9 | 89 | 470 | 694 | 863 | 780 | 488 | 429 | 562 | 488 | 327 | 132 |
| February | 5 | 67 | 472 | 587 | 822 | 627 | 441 | 411 | 410 | 327 | 289 | 86 |
| March | 3 | 93 | 483 | 390 | 637 | 590 | 447 | 434 | 340 | 303 | 113 | 124 |
| April | 22 | 117 | 396 | 391 | 405 | 379 | 306 | 250 | 431 | 246 | 41 | 60 |
| May | 30 | 117 | 362 | 356 | 345 | 317 | 271 | 300 | 290 | 288 | 20 | 64 |
| June | 18 | 127 | 341 | 235 | 302 | 373 | 321 | 238 | 277 | 216 | 19 | 121 |
| July | 54 | 269 | 475 | 331 | 667 | 487 | 343 | 338 | 366 | 249 | 55 | 117 |
| August | 43 | 235 | 418 | 326 | 510 | 502 | 384 | 430 | 457 | 229 | 41 | 112 |
| September | 50 | 277 | 554 | 490 | 477 | 485 | 381 | 377 | 370 | 311 | 39 | 131 |
| October | 45 | 359 | 574 | 588 | 534 | 429 | 325 | 348 | 228 | 211 | 38 | 47 |
| November | 49 | 301 | 419 | 527 | 494 | 433 | 272 | 317 | 164 | 210 | 39 | 139 |
| December | 14 | 315 | 376 | 456 | 366 | 378 | 348 | 255 | 151 | 216 | 19 | 74 |
| Total | 342 | 2366 | 5340 | 5371 | 6422 | 5780 | 4327 | 4127 | 4046 | 3294 | 1040 | 1207 |
Table A2.
Total Monthly Number of Scabies Cases Recorded in the PPS Registry from January 2009 to December 2021
| Month | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| January | 7 | 20 | 27 | 37 | 14 | 45 | 21 | 13 | 17 | 12 | 9 | 2 | 0 |
| February | 10 | 32 | 16 | 9 | 17 | 28 | 21 | 30 | 6 | 6 | 7 | 12 | 2 |
| March | 15 | 35 | 14 | 19 | 22 | 23 | 23 | 13 | 11 | 22 | 17 | 19 | 0 |
| April | 13 | 35 | 17 | 14 | 6 | 33 | 9 | 8 | 7 | 17 | 14 | 1 | 0 |
| May | 39 | 28 | 17 | 11 | 7 | 10 | 17 | 6 | 19 | 5 | 2 | 10 | 0 |
| June | 29 | 6 | 21 | 7 | 8 | 16 | 3 | 6 | 1 | 8 | 3 | 3 | 1 |
| July | 9 | 7 | 21 | 7 | 4 | 7 | 10 | 28 | 3 | 7 | 12 | 6 | 12 |
| August | 16 | 0 | 23 | 7 | 15 | 17 | 21 | 29 | 7 | 7 | 11 | 3 | 7 |
| September | 10 | 15 | 13 | 11 | 23 | 6 | 18 | 18 | 10 | 24 | 3 | 0 | 9 |
| October | 26 | 11 | 13 | 18 | 6 | 2 | 14 | 19 | 13 | 24 | 9 | 2 | 4 |
| November | 22 | 28 | 25 | 7 | 15 | 22 | 21 | 5 | 20 | 56 | 5 | 0 | 8 |
| December | 24 | 17 | 22 | 5 | 14 | 18 | 5 | 12 | 17 | 42 | 8 | 8 | 21 |
| Total | 220 | 234 | 229 | 152 | 151 | 227 | 183 | 187 | 131 | 230 | 100 | 66 | 64 |
Table A3.
Total Annual Number (Percentage) of Scabies Cases among Pediatric Age Groups Recorded in the PDS and PPS Registry from 2009 to 2021
| Year | <1 y | 1-4 y | 5-9 y | 10-14 y | 15-18 y | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| PDS | PPS | PDS | PPS | PDS | PPS | PDS | PPS | PDS | PPS | |
| 2009 | – | 148 (67.3%) | – | 24 (10.9%) | – | 25 (11.4%) | – | 19 (8.6%) | – | 4 (1.8%) |
| 2010 | 20 (12.3%) | 134 (58.8%) | 54 (33.1%) | 62 (27.2%) | 37 (22.7%) | 21 (9.2%) | 28 (17.2%) | 11 (4.8%) | 24 (14.7%) | – |
| 2011 | 115 (8.8%) | 122 (53.3%) | 587 (44.9%) | 69 (30.1%) | 288 (22.0%) | 16 (7.0%) | 204 (15.6%) | 22 (9.6%) | 114 (8.7%) | – |
| 2012 | 348 (11.5%) | 83 (54.6%) | 1284 (42.3%) | 40 (26.3%) | 688 (22.7%) | 18 (11.8%) | 403 (13.3%) | 7 (4.6%) | 311 (10.3%) | 4 (2.6%) |
| 2013 | 331 (11.2%) | 86 (57.0%) | 1198 (40.4%) | 51 (33.8%) | 672 (22.6%) | 7 (4.6%) | 432 (14.6%) | 4 (2.6%) | 335 (11.3%) | 3 (2.0%) |
| 2014 | 321 (8.7%) | 97 (43.3%) | 1334 (36.2%) | 58 (25.9%) | 822 (22.3%) | 45 (20.1%) | 579 (15.7%) | 24 (10.7%) | 632 (17.1%) | – |
| 2015 | 284 (9.4%) | 75 (41.0%) | 1092 (36.1%) | 55 (30.1%) | 808 (26.7%) | 27 (14.8%) | 504 (16.7%) | 20 (10.9%) | 338 (11.2%) | 6 (3.3%) |
| 2016 | 201 (9.2%) | 107 (57.2%) | 779 (35.6%) | 56 (29.9%) | 567 (25.9%) | 12 (6.4%) | 363 (16.6%) | 9 (4.8%) | 276 (12.6%) | 3 (1.6%) |
| 2017 | 152 (7.8%) | 64 (48.9%) | 655 (33.6%) | 43 (32.8%) | 513 (26.3%) | 9 (6.9%) | 363 (18.6%) | 10 (7.6%) | 265 (13.6%) | 5 (3.8%) |
| 2018 | 158 (8.9%) | 67 (29.1%) | 504 (28.3%) | 104 (45.2%) | 450 (25.3%) | 50 (21.7%) | 362 (20.3%) | 9 (3.9%) | 306 (17.2%) | – |
| 2019 | 82 (5.6%) | 48 (46.6%) | 457 (31.2%) | 27 (26.2%) | 384 (26.2%) | 9 (8.7%) | 285 (19.5%) | 16 (15.5%) | 255 (17.4%) | 3 (2.9%) |
| 2020 | 24 (5.9%) | 30 (44.8%) | 130 (32.2%) | 6 (9.0%) | 115 (28.5%) | 12 (17.9%) | 66 (16.3%) | 16 (23.9%) | 69 (17.1%) | 3 (4.5%) |
| 2021 | 38 (7.9%) | 28 (43.8%) | 141 (29.3%) | 8 (12.5%) | 127 (26.4%) | 11 (17.2%) | 98 (20.4%) | 16 (25.0%) | 77 (16.0%) | 1 (1.6%) |
| Total | 2074 | 1089 | 8215 | 603 | 5471 | 262 | 3687 | 183 | 3002 | 32 |
Table A4.
Total Annual Number (Percentage) of Scabies Cases among Adult Age Groups Recorded in the PDS and PPS Registry from 2010 to 2021
| Year | 19-24 y | 25-29 y | 30-34 y | 35-39 y | 40-44 y | 45-49 y | 50-54 y | 55-59 y | 60-64 y | 65-69 y | 70-74 y | ≥75 y |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2010 | 24 (14.5%) | 11 (6.7%) | 22 (13.3%) | 12 (7.3%) | 17 (10.3%) | 20 (12.1%) | 17 (10.3%) | 16 (9.7%) | 11 (6.7%) | 7 (4.2%) | 6 (3.6%) | 2 (1.2%) |
| 2011 | 238 (23.8%) | 112 (11.2%) | 108 (10.8%) | 108 (10.8%) | 78 (7.8%) | 78 (7.8%) | 74 (7.4%) | 55 (5.5%) | 61 (6.1%) | 31 (3.1%) | 33 (3.3%) | 24 (2.4%) |
| 2012 | 463 (22.2%) | 277 (13.3%) | 222 (10.7%) | 189 (9.1%) | 198 (9.5%) | 183 (8.8%) | 137 (6.6%) | 114 (5.5%) | 104 (5.0%) | 73 (3.5%) | 64 (3.1%) | 60 (2.9%) |
| 2013 | 505 (22.7%) | 319 (14.3%) | 260 (11.7%) | 209 (9.4%) | 184 (8.3%) | 190 (8.5%) | 141 (6.3%) | 112 (5.0%) | 102 (4.6%) | 68 (3.1%) | 65 (2.9%) | 68 (3.1%) |
| 2014 | 579 (22.8%) | 344 (13.5%) | 288 (11.3%) | 255 (10.0%) | 215 (8.4%) | 203 (8.0%) | 182 (7.2%) | 122 (4.8%) | 129 (5.1%) | 104 (4.1%) | 62 (2.4%) | 62 (2.4%) |
| 2015 | 587 (22.2%) | 365 (13.8%) | 281 (10.6%) | 257 (9.7%) | 265 (10.0%) | 203 (7.7%) | 188 (7.1%) | 148 (5.6%) | 118 (4.5%) | 99 (3.7%) | 57 (2.2%) | 78 (2.9%) |
| 2016 | 401 (20.0%) | 292 (14.6%) | 215 (10.7%) | 178 (8.9%) | 193 (9.6%) | 184 (9.2%) | 139 (6.9%) | 121 (6.0%) | 105 (5.2%) | 86 (4.3%) | 42 (2.1%) | 50 (2.5%) |
| 2017 | 407 (19.6%) | 253 (12.2%) | 201 (9.7%) | 211 (10.2%) | 219 (10.6%) | 182 (8.8%) | 161 (7.8%) | 115 (5.5%) | 130 (6.3%) | 84 (4.0%) | 56 (2.7%) | 56 (2.7%) |
| 2018 | 482 (22.1%) | 248 (11.4%) | 217 (9.9%) | 205 (9.4%) | 179 (8.2%) | 185 (8.5%) | 174 (8.0%) | 147 (6.7%) | 139 (6.4%) | 80 (3.7%) | 54 (2.5%) | 72 (3.3%) |
| 2019 | 370 (20.6%) | 263 (14.6%) | 190 (10.6%) | 165 (9.2%) | 173 (9.6%) | 152 (8.5%) | 123 (6.8%) | 93 (5.2%) | 124 (6.9%) | 60 (3.3%) | 44 (2.4%) | 40 (2.2%) |
| 2020 | 163 (26.7%) | 84 (13.7%) | 75 (12.3%) | 50 (8.2%) | 54 (8.8%) | 56 (9.2%) | 38 (6.2%) | 25 (4.1%) | 36 (5.9%) | 10 (1.6%) | 8 (1.3%) | 12 (2.0%) |
| 2021 | 173 (24.6%) | 128 (18.2%) | 81 (11.5%) | 65 (9.2%) | 53 (7.5%) | 58 (8.2%) | 34 (4.8%) | 41 (5.8%) | 30 (4.3%) | 22 (3.1%) | 8 (1.1%) | 11 (1.6%) |
| Total | 4392 | 2696 | 2160 | 1904 | 1828 | 1694 | 1408 | 1109 | 1089 | 724 | 499 | 535 |
Table A5.
Total Annual Number of Scabies Cases according to Sex Recorded in the PDS and PPS Registries from 2009 to 2021
| Year | Total | Male | Female | Sex ratio | ||||
|---|---|---|---|---|---|---|---|---|
| PDS | PPS | PDS | PPS | PDS | PPS | PDS | PPS | |
| 2009 | 220 | 118 | 102 | 1.2 | ||||
| 2010 | 328 | 234 | 169 | 151 | 159 | 83 | 1.1 | 1.8 |
| 2011 | 2308 | 229 | 1095 | 122 | 1213 | 107 | 0.9 | 1.1 |
| 2012 | 5104 | 152 | 2698 | 80 | 2406 | 72 | 1.1 | 1.1 |
| 2013 | 5193 | 151 | 2678 | 97 | 2515 | 54 | 1.1 | 1.8 |
| 2014 | 6233 | 227 | 3221 | 122 | 3012 | 105 | 1.1 | 1.2 |
| 2015 | 5672 | 183 | 2577 | 91 | 3095 | 92 | 0.8 | 1.0 |
| 2016 | 4192 | 187 | 1851 | 103 | 2341 | 84 | 0.8 | 1.2 |
| 2017 | 4022 | 131 | 1782 | 75 | 2240 | 56 | 0.8 | 1.3 |
| 2018 | 3962 | 230 | 1796 | 124 | 2166 | 106 | 0.8 | 1.2 |
| 2019 | 3262 | 100 | 1516 | 45 | 1746 | 55 | 0.9 | 0.8 |
| 2020 | 1015 | 66 | 454 | 41 | 561 | 25 | 0.8 | 1.6 |
| 2021 | 1185 | 64 | 514 | 43 | 671 | 21 | 0.8 | 2.0 |
| Total | 42476 | 2174 | 20351 | 1212 | 22125 | 962 | ||
PDS, Philippine Dermatological Society. PPS, Philippine Pediatric Society
Table A6.
Total Annual Frequency of Scabies Cases according to Diagnosis Recorded in the PPS Registry from 2009 to 2021
| Year | Primary | Secondary | Tertiary |
|---|---|---|---|
| 2009 | 92 (42%) | 128 (58%) | 0 (0%) |
| 2010 | 94 (40%) | 140 (60%) | 0 (0%) |
| 2011 | 91 (40%) | 138 (60%) | 0 (0%) |
| 2012 | 70 (46%) | 82 (54%) | 0 (0%) |
| 2013 | 69 (46%) | 82 (54%) | 0 (0%) |
| 2014 | 105 (46%) | 122 (54%) | 0 (0%) |
| 2015 | 79 (43%) | 104 (57%) | 0 (0%) |
| 2016 | 79 (42%) | 108 (58%) | 0 (0%) |
| 2017 | 67 (51%) | 64 (49%) | 0 (0%) |
| 2018 | 156 (68%) | 74 (32%) | 0 (0%) |
| 2019 | 52 (52%) | 45 (45%) | 3 (3%) |
| 2020 | 34 (52%) | 32 (48%) | 0 (0%) |
| 2021 | 24 (38%) | 22 (34%) | 18 (28%) |
| Total | 1091 | 1223 | 21 |
PPS, Philippine Pediatric Society
Statement of Authorship
RNFG contributed in the conceptualization of work, data collection and analysis, and writing of final manuscript. EQV contributed in the data collection and analysis, writing of final manuscript, and approval of final manuscript. VRCA contributed in the data collection and approval of final manuscript. MSFSC contributed in the conceptualization of work and final approval of the version to be published.
Author Disclosure
The authors do not have any declared conflicts of interest.
REFERENCES
- 1.Census Office Philippines . Census of the Philippine Islands Taken Under the Direction of the Philippine Legislature in the Year 1918. Bureau of Printing [Internet]. 1921. [cited 2022 Nov 3]. Available from: https://books.google.com.ph/books/about/Census_of_the_Philippine_Islands_Taken_U.html?id=noT815qG-u0C&redir_esc=y#v=onepage&q=scabies%20philippines&f=false
- 2.Schmidt L. American Involvement in the World War II Filipino Resistance Movement on Mindanao during the Japanese Occupation, 1942-1945. 1982. United States Department of the Army: Kansas, USA. [Google Scholar]
- 3.n.a . Scabies increasing in alarming proportions urge strengthening STD contact tracing raise possible resurgence of Yaws. Filip Fam Physician. 1975;13(4):27. [Google Scholar]
- 4.Simuangco SA. Geographic dermatology: the Philippines. Acta Med Philipp. 1975. Jul Dec;11(2):37–43. [Google Scholar]
- 5.Romero R. National prevalence survey of fungal and skin diseases. J Phil Dermatol Soc. 1999;8(2):115–9. [Google Scholar]
- 6.Dofitas B, Ramiro L, Amarillo L, Beringuela A, Fajutrao L. Healthseeking behavior of Filipinos with skin ailments: focus on leprosy prevention and management. Unpublished thesis for MS Clinical Epidemiology. College of Medicine, University of the Philippines Manila; 2005. [Google Scholar]
- 7.Cabato L. Humanitarian worker from S. Korea shares experience working at PH detention facility. Manila Bulletin. September 20, 2022. [Google Scholar]
- 8.Maderazo IR, Penilla C, Balingit JE, Yiehdiego G. Eradicating scabies in crowded jail setting: mass treatment using benzyl benzoate lotion 25%. In: FaceBook Page. World Prison Conference, Geneva, Switzerland, June 27-29, 2022; 2021. [Google Scholar]
- 9.Population | Department of Health website [Internet]. 2016. [cited 2023 Jan 4]. Available from: https://doh.gov.ph/population
- 10.Philippine Statistics Authority . 2020 Census of Population and Housing (2020 CPH). Population Counts Declared Official by the President [Internet]. 2020. [cited 2023 Jan 4]. Available from: https://psa.gov.ph/sites/default/files/attachments/ird/pressrelease/Table%20A%20-%20Population%20and%20Annual%20Growth%20Rate%20for%20the%20Philippines%20and%20its%20Regions%2C%20Provinces%2C%20and%20Highly%20Urbanized%20Cities_AGBA_0.xlsx
- 11.Philippine Atmospheric Geophysical and Astronomical Services Administration . Climate of the Philippines [Internet]. N.d.. [cited 2022 Dec 12]. Available from: https://www.pagasa.dost.gov.ph/information/climate-philippines
- 12.Department of Health . The 2020 Revised Implementing Rules and Regulations of Republic Act No.11332, or the Mandatory Reporting of Notifiable Diseases and Health Events of Public Health Concern Act [Internet]. 2020. [cited 2023 Jan 6]. Available from: https://doh.gov.ph/sites/default/files/health-update/revised-IRR-RA11332.pdf
- 13.Urban K, Chu S, Giesey RL, Mehrmal S, Uppal P, Dolost ME, et al. Burden of skin disease and associated socioeconomic status in Asia: A cross-sectional analysis from the Global Burden of Disease Study 1990-2017. JAAD Int. 2020. Dec;2:40–50. doi: 10.1016/j.jdin.2020.10.006 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Karimkhani C, Colombara DV, Drucker AM, Norton SA, Hay R, Engelman D, et al. The global burden of scabies: a cross-sectional analysis from the Global Burden of Disease Study 2015. Lancet Infect Dis. 2017. Dec;17(12):1247–54. doi: 10.1016/S1473-3099(17)30483-8 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Engelman D, Marks M, Steer AC, Beshah A, Biswas G, Chosidow O, et al. A framework for scabies control. PLoS Negl Trop Dis. 2021. Sep;15(9):e0009661. doi: 10.1371/journal.pntd.0009661 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.World Health Organization (WHO) . WHO Informal Consultation on a Framework for Scabies Control Meeting Report, Manila, Philippines (19–21 February 2019) [Internet]. 2020. [cited 2023 Jan 6]. Available from: https://www.who.int/publications/i/item/9789240008069
- 17.World Health Organization . Ending the Neglect to Attain the Sustainable Development Goals [Internet]. 2020. [cited 2023 Jan 6]. Available from: https://apps.who.int/iris/handle/10665/70809
- 18.Dermatology Lexicon - Summary | NCBO BioPortal [Internet]. [cited 2023 Feb16]. Available from: https://bioportal.bioontology.org/ontologies/DERMLEX
- 19.ICD-10. ICD-10 coding [Internet]. [cited 2022 Dec 6]. Available from: https://www.icd10data.com/ICD10CM/Codes/A00-B99/B85-B89/B86-.
- 20.About Us – Philippine Pediatric Society, Inc. [Internet]. 2023. [cited 2023 Feb 17]. Available from: https://pps.org.ph/about-us/
- 21.Philippine Pediatric Society . Philippine Pediatric Society Disease Registry Hospital List [Internet]. 2023. [cited 2023 Feb 15]. Available from: https://pps.ivant.com/hospital.do
- 22.StataCorp . 2021. Stata Statistical Software: Release 17. College Station, TX: StataCorp LLC. [Google Scholar]
- 23.Karaca Ural Z, Çatak B, Ağaoğlu E. Prevalence of scabies in the COVID-19 pandemic period and determination of risk factors for scabies: a hospital-based cross-sectional study in Northeast Turkey. Acta Parasitol. 2022. Jun;67(2):802–8. doi: 10.1007/s11686-022-00524-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Aktaş H, Cebecik A. Changes in incidence and age distribution of scabies: A retrospective cohort study in a tertiary hospital. Arch Clin Exp Med. 2019;4(1):21–4. doi: 10.25000/acem.454426 [DOI] [Google Scholar]
- 25.Kutlu Ö, Aktaş H. The explosion in scabies cases during COVID-19 pandemic. Dermatol Ther. 2020. Sep;33(5):e13662. doi: 10.1111/dth.13662 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.van Deursen B, Hooiveld M, Marks S, Snijdewind I, van den Kerkhof H, Wintermans B, et al. Increasing incidence of reported scabies infestations in the Netherlands, 2011–2021. PLoS One. 2022. Jun;17(6):e0268865. doi: 10.1371/JOURNAL.PONE.0268865 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Griffin LR, Pender EK, Laing ME, Markham T. Unexpected consequences of SARS-CoV-2 pandemic: scabies infestation. Clin Exp Dermatol. 2022. Jun;47(6):1196–7. doi: 10.1111/CED.15151 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Inter-Agency Task Force (for the Management of Emerging Infectious Diseases) . Omnibus Guidelines on the Implementation of Community Quarantine in the Philippines [Internet]. 2020. [cited 2023 Jan 6]. Available from: https://www.officialgazette.gov.ph/2021/09/23/omnibus-guidelines-on-the-implementation-of-community-quarantine-in-the-philippines-with-amendments-as-of-september-23-2021/
- 29.Kim J H, Cheong H K. Epidemiologic trends and seasonality of scabies in South Korea. Korean J Parasitol. 2019. Aug;57(4):399–404. doi: 10.3347/kjp.2019.57.4.399. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Liu JM, Wang HW, Chang FW, Liu YP, Chiu FH, Lin YC, et al. The effects of climate factors on scabies. A 14-year population-based study in Taiwan. Parasite. 2016;23:54. doi: 10.1051/PARASITE/2016065 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Sanei-Dehkordi A, Soleimani-Ahmadi M, Zare M, Jaberhashemi SA. Risk factors associated with scabies infestation among primary schoolchildren in a low socio-economic area in southeast of Iran. BMC Pediatr. 2021. May;21(1):249. doi: 10.1186/s12887-021-02721-0 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Mimouni D, Ankol OE, Davidovitch N, Gdalevich M, Zangvil E, Grotto I. Seasonality trends of scabies in a young adult population: a 20-year follow-up. Br J Dermatol. 2003. Jul;149(1):157–9. doi: 10.1046/J.1365-2133.2003.05329.X [DOI] [PubMed] [Google Scholar]
- 33.Aždajić MD, Bešlić I, Gašić A, Ferara N, Pedić L, Lugović-Mihić L. Increased scabies incidence at the beginning of the 21st century: What do reports from Europe and the World Show? Life. 2022. Oct;12(10):1598. doi: 10.3390/life12101598 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Korycińska J, Dzika E, Kloch M. Epidemiology of scabies in relation to socio-economic and selected climatic factors in North-east Poland. Ann Agric Environ Med. 2020. Sep;27(3):374–8. doi: 10.26444/AAEM/109319 [DOI] [PubMed] [Google Scholar]
- 35.Arlian LG, Runyan RA, Achar S, Estes SA. Survival and infectivity of Sarcoptes scabiei var. canis and var. hominis. J Am Acad Dermatol. 1984. Aug;11(2 Pt 1):210–5. doi: 10.1016/S0190-9622(84)70151-4 [DOI] [PubMed] [Google Scholar]
- 36.Lynar S, Currie BJ, Baird R. Scabies and mortality. Lancet Infect Dis. 2017. Dec;17(12):1234. doi: 10.1016/S1473-3099(17)30636-9 [DOI] [PubMed] [Google Scholar]
- 37.Roberts LJ, Huffam SE, Walton SF, Currie BJ. Crusted scabies: clinical and immunological findings in seventy-eight patients and a review of the literature. J Infect. 2005. Jun;50(5):375–81. doi: 10.1016/J.JINF.2004.08.033 [DOI] [PubMed] [Google Scholar]
- 38.Sulasmia, Djuardi I, Djamaluddin W, Madjid A, Amin S, Adriani A, et al. Crusted scabies: Presenting as erythroderma in a patient with hepatitis B. J Phil Dermatol Soc. 2018. [Google Scholar]
- 39.Nadela SE, Perlas MCFB, Fevrier H, Manalili HFP, Dayrit JF. Crusted (Norwegian) scabies in an infant: a case report. J Phil Dermatol Soc. 2020;96–9. [Google Scholar]
- 40.Kouotou EA, Nansseu JRN, Kouawa MK, Zoung-Kanyi Bissek AC. Prevalence and drivers of human scabies among children and adolescents living and studying in Cameroonian boarding schools. Parasit Vectors. 2016. Jul;9(1):400. doi: 10.1186/s13071-016-1690-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 41.Argentina F, Harahap DH, Lusiana E. Risk factors of scabies in students of Aulia Cendikia Islamic Boarding School, Palembang. JKK. 2019. Oct;6(3):96–9. doi: 10.32539/JKK.V6I3.9851 [DOI] [Google Scholar]
- 42.Anderson KL, Strowd LC. Epidemiology, diagnosis, and treatment of scabies in a dermatology office. J Am Board Fam Med. 2017. Jan;30(1):78–84. doi: 10.3122/jabfm.2017.01.160190 [DOI] [PubMed] [Google Scholar]
- 43.The World Bank . Labor force, female (% of total labor force) – Philippines [Internet]. 2021. [cited 2023 Feb]. Available from: https://data.worldbank.org/indicator/SL.TLF.TOTL.FE.ZS?locations=PH.
- 44.Trinos JPCRD, Wulandari LPL, Clarke N, Belizario V, Kaldor J, Nery SV. Prevalence of soil-transmitted helminth infections, schistosomiasis, and lymphatic filariasis before and after preventive chemotherapy initiation in the Philippines: A systematic review and meta-analysis. PloS Negl Trop Dis. 2021. Dec;15(12):e0010026. doi: 10.1371/JOURNAL.PNTD.0010026 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 45.Sanitation targets are off-track: DOH, WHO and UNICEF ask local governments to invest in sanitation [Internet]. 2020. [cited 2023 Jan 4]. Available from: https://www.unicef.org/philippines/press-releases/sanitation-targets-are-track-doh-who-and-unicef-ask-local-governments-invest
- 46.Restoring access to clean water and sanitation facilities in Southern Leyte after Typhoon Odette | UNICEF Philippines [Internet]. 2022. [cited 2023 Jan 4]. Available from: https://www.unicef.org/philippines/stories/restoring-access-clean-water-and-sanitation-facilities-southern-leyte-after-typhoon-odette
- 47.Roswendi AS, Zakiyah Y. Relationship between environmental sanitation and the incidence of scabies: a literature review. KnE Medicine. June 3, 2022. doi: 10.18502/kme.v2i2.11083 [DOI] [Google Scholar]