Abstract
OBJECTIVE
Preseptal cellulitis is an infection of the palpebrae and the periorbital superficial tissue and is more common in children than adults. This study aims to evaluate the demographic and clinical characteristics of children hospitalized for preseptal cellulitis and the factors affecting these characteristics.
METHODS
In this retrospective, single-center study, 101 children hospitalized for preseptal cellulitis between March 2019 and March 2022 were included. The patients were divided into 2 groups as under five years old and over five years old.
RESULTS
56 patients (55.4%) were male and the median age was 56 (24–89) months. All patients had eye swelling. Periorbital erythema was seen in 81 (80.1%), conjunctivitis in 39 (38.6%), eye discharge in 30 (29.7%) patients. The most common treatment was ampicillin-sulbactam+clindamycin (77.2%). Mean treatment duration was 8.42±2.89 days, clinical improvement was 5.01±2.20 days. Patients with leukocytosis had longer duration of treatment compared to patients without leukocytosis (9.3±3.1 vs. 7.8±2.5 days, p=0.009). While the lymphocyte level was higher in patients under 5 years of age compared to patients over 5 years of age (p<0.001); neutrophil (p<0.001), hemoglobin (p=0.002) and NLR (p<0.001) levels were low. The duration of clinical improvement was short in patients under 5 years of age (4.4±1.6 vs. 5.6±2.5 days, p=0.005).
CONCLUSION
The most common finding in patients with preseptal cellulitis was swelling in the eye. The presence of leukocytosis in patients may be used to predict the duration of treatment. Age was an important factor in predicting the duration of clinical improvement in patients.
Keywords: Children, eye, preseptal cellulitis
Highlight key points
Incompletely treated sinusitis and buccal infections are the most common causes of preseptal cellulitis.
Age is a factor affecting the clinical healing process in patients with preseptal cellulitis.
Initial leukocyte values can be used to determine the duration of treatment.
Complications can be prevented with early diagnosis, correct and adequate treatment.
Preseptal cellulitis is an infection of the anterior portion of the eyelid, not involving the orbit or other ocular structures. It rarely causes serious complications. Therefore, it requires rapid diagnosis and treatment. Preseptal cellulitis is common in childhood and often develops after trauma and sinusitis [1, 2]. Patients usually present with ocular pain, eyelid swelling, and erythema. Orbital cellulitis may present with additional ocular symptoms, such as proptosis, eye pain, decreased vision, and limited extraocular motility [2, 3].
Preseptal and orbital cellulitis are two infections surrounding the orbital septum with very different potential outcomes. Diagnosis is based on clinical examination and computed tomography (CT) imaging of the orbit and sinuses. A history of sinusitis, insect bites, or local facial or eyelid trauma supports the diagnosis. Preseptal cellulitis is much more common than orbital cellulitis, and both are more common in children than adults [3, 4]. Preseptal cellulitis is most commonly caused by bacteria such as Staphylococcus aureus and Streptococcus, and it resolves after 5–7 days with appropriate antibiotic therapy [5, 6]. In this study, we evaluated the demographic and clinical characteristics of children hospitalized for preseptal cellulitis and the factors affecting them.
MATERIALS AND METHODS
Study Design
This retrospective single-center study included 101 children hospitalized for preseptal cellulitis between March 2019 and 2022. It excluded patients aged >18 years or with comorbid diseases, outpatient treatment, and unclear differential diagnoses (Fig. 1). All patients’ clinical variables and laboratory test panels during hospitalization were obtained from medical records. Data on demographics (e.g., age and sex), medical treatment, hospitalization, treatment duration, clinical recovery duration, and the presence of predisposing factors were also obtained from medical records. The patients were divided by age into two groups: ≤five and >five years.
Figure 1.
Flowchart of the study.
The period before the age of five is infancy and preschool, and this distinction was made due to etiological differences. Normal age-based levels were used for hemoglobin, leukocytosis, and leukopenia in laboratory results [7]. This study complied with the Declaration of Helsinki. The study protocol was approved by the Haseki Training and Research Hospital Ethics Committee and the Ministry of Health (approval no: 85-2022; date: May 11, 2022).
Management and Treatment
The preseptal cellulitis diagnosis was made according to the patients’ clinical, laboratory, and radiological features. A pediatrician and an ophthalmologist diagnosed patients who did not undergo CT. Some of the patients received oral antibiotics after discharge. Treatment was determined according to the patient’s general condition, symptom severity, laboratory results at hospitalization and follow-up, treatment response, and time to duration of clinical improvement. An infectious disease specialist and pediatrician determined all patients’ treatment regimens. Teicoplanin treatment was added to patients who did not clinically improve after 48 hours of treatment. Clinical improvement was defined as regression of the patient’s erythema and ocular findings, improvement in their general condition, and improvement in laboratory values (acute phase reactants such as white blood cells and C-reactive protein). All patients were followed up by at least three doctors, one infectious diseases specialist, and two pediatricians.
Statistical Analysis
All statistical analyses were performed using the Statistical Package for the Social Sciences 22.0 for Windows (IBM Corp, Armonk, NY, USA). The Kolmogorov–Smirnov test was used to assess the normality of the data. Normally distributed continuous variables are expressed as the mean±standard deviation and were compared between groups using Student’s t-test. Nonnormally distributed variables are expressed as the median (25th–75th percentiles) and were compared between groups using the Mann–Whitney U test. Categorical variables are expressed as percentages and were compared between groups using the Chi-square test. All results with a two-sided p-value of <0.05 were considered statistically significant.
RESULTS
Demographics and Clinical and Laboratory Findings of Preseptal Cellulitis Cases
The clinical and demographic characteristics of the 101 children hospitalized for preseptal cellulitis are shown in Table 1. Fifty-six were male (55.4%). The median age of all 101 patients was 56 (24–89) months. Median age did not differ significantly between male (52 [25–94] months) and female (58 [24–86] months) patients (p=0.920). All patients included in this study had eyelid swelling. Eyelid erythema was present in 81 (80.2%) patients, conjunctival erythema in 39 (38.6%), purulent discharge in 30 (29.7%), and fever in 12 (11.9%). The right eye was involved in 43 patients (42.6%), the left eye in 50 (49.5%), and both eyes in eight (7.9%). There was no significant relationship between the frequencies of clinical findings and sex (p=0.510).
Table 1.
Demographic and clinical data of the study population
| Variables | Total (n=101) |
|---|---|
| Boy, (%) | 55.4 |
| Age (months), (25th–75th percentile) | 56 (24–89) |
| Patients under five years old, (%) | 53.5 |
| Complaints and clinical findings, (%) | |
| Eyelid swelling | 100 |
| Eyelid erythema | 80.2 |
| Purulent discharge | 20.7 |
| Fever | 11.9 |
| Conjunctival erythema | 38.6 |
| Eye involvement | |
| Right eye | 42.6 |
| Left eye | 49.5 |
| Bilateral | 7.9 |
| Predisposing factors, (%) | |
| Sinusitis | 18.8 |
| Buccal infection | 16.8 |
| Insect bite | 12.8 |
| Herpes infection | 8.9 |
| Trauma | 6.9 |
| Complicated upper respiratory tract infection | 4 |
| Foreign body infections | 3 |
| Seasonal distribution (%) | |
| Spring | 44.5 |
| Summer | 16.8 |
| Autumn | 10.8 |
| Winter | 27.7 |
| Laboratory findings | |
| Hemoglobin (g/dl) | 12.6±1.6 |
| WBC (/mm3) | 12113±4900 |
| Neutrophil (/mm3) | 6938 (4230–8400) |
| Lymphocyte (/mm3) | 3850 (2570–4420) |
| NLR | 1.65 (0.98–2.98) |
| Platelet (/mm3) | 333131±96884 |
| CRP (g/L) | 20.9 (1.1–22.8) |
| Treatment, (%) | |
| Ampicillin-sulbactam + clindamycin | 77.2 |
| Ampicillin-sulbactam + acyclovir | 4.9 |
| Ampicillin-sulbactam + teicoplanin | 8.9 |
| Ceftriaxone | 8.9 |
| Sequential oral therapy, (%) | 69.3 |
| Treatment durations (days) | 8.42±2.89 |
| Clinical improvement (days) | 5.01±2.20 |
WBC: White blood cell; NLR: Neutrophil lymphocyte ratio; CRP: C-Reactive protein. Values are given as mean±standard deviation or median (25th–75th percentile).
The predisposing factors were sinusitis in 19 patients (18.8%), buccal infection in 17 (16.8%), insect bite in 13 (12.8%), herpes infection in nine (8.9%), trauma in seven (6.9%), upper respiratory tract infection in four (4%), and foreign body in three (3%). Since this was a retrospective study, no predisposing factor could be determined for other patients. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction was negative for all patients between March 11, 2020, and March 1, 2022. Preseptal cellulitis was most common in spring (44.5%), followed by winter (27.7%), summer (16.8%), and autumn (10.8%).
An orbital CT was performed for 85 patients (84.2%) to confirm the diagnosis and exclude orbital cellulitis. All CT images were compatible with preseptal cellulitis. Periorbital thickening was seen in 67 patients (78.8%), edema in 32 (37.6%), and increased density in 27 (31.7).
Seventy patients (69.3%) were treated orally after discharge. The average treatment duration of the patients was 8.4±2.8 days, and their time to clinical improvement was 5.0±2.2 days. There were no significant correlations between the time to clinical improvement and parameters other than age.
No patients developed orbital cellulitis or other complications.
Age-Based Comparisons of Demographics, Clinical and Laboratory Findings, and Treatment
The patients were divided by age into two groups: <five (n=54) and >five (n=47) years (Table 2). The sex ratio did not differ significantly between age groups (p=0.050).
Table 2.
Demographic and clinical data of patients according to age groups
| Variables | Under five years old (n=54) | Above five years old (n=47) | p |
|---|---|---|---|
| Boy, (%) | 55.5 | 55.3 | 0.920 |
| Complaints and clinical findings, (%) | |||
| Eyelid erythema | 81.5 | 78.7 | 0.762 |
| Purulent discharge | 35.1 | 23.4 | 0.200 |
| Fever | 13 | 10.6 | 0.710 |
| Conjunctival erythema | 44.4 | 31.9 | 0.200 |
| Eye involvement | |||
| Right eye | 55.5 | 27.6 | 0.004 |
| Left eye | 33.3 | 68 | <0.001 |
| Bilateral | 11.1 | 4.2 | 0.200 |
| Predisposing factors, (%) | |||
| Sinusitis | 11.1 | 27.6 | 0.002 |
| Buccal infection | 13 | 21.2 | 0.270 |
| Insect bite | 11.1 | 14.9 | 0.420 |
| Herpes infection | 3.7 | 14.9 | 0.050 |
| Trauma | 5.5 | 8.5 | 0.340 |
| Seasonal distribution, (%) | |||
| Spring | 38.9 | 51 | 0.220 |
| Summer | 16.7 | 17 | 0.960 |
| Autumn | 16.7 | 4.2 | 0.045 |
| Winter | 27.8 | 27.6 | 0.980 |
| CT findings, (%) | |||
| Thickness increase | 66.7 | 65.9 | 0.940 |
| Edema | 25.9 | 38 | 0.190 |
| Density increase | 20.3 | 34 | 0.120 |
| Laboratory findings | |||
| Hemoglobin (g/dl) | 12.17±1.30 | 13.12±1.75 | 0.002 |
| WBC (/mm3) | 12536±4912 | 11606±4891 | 0.350 |
| Neutrophil (/mm3) | 5675(4032-6830) | 7310 (4705-9605) | <0.001 |
| Lymphocyte (/mm3) | 3945 (3252-5737) | 2650 (2020-3280) | <0.001 |
| NLR | 1.26 (0.80-1.73) | 2.54 (1.73-4.01) | <0.001 |
| Platelet (/mm3) | 330648±108349 | 336111±82153 | 0.780 |
| CRP (g/L) | 5.35 (1.33-16.38) | 9.4 (1.1-27.4) | 0.500 |
| Leukocytosis, (%) | 31.5 | 48.9 | 0.080 |
| Treatment, n (%) | |||
| Sequential oral therapy, (%) | 68.5 | 70.2 | 0.850 |
| Treatment durations (days) | 7.93±2.63 | 8.98±3.11 | 0.070 |
| Clinical improvement (days) | 4.43±1.60 | 5.68±2.58 | 0.005 |
CT: Computed Tomography; WBC: White blood cell; NLR: Neutrophil lymphocyte ratio; CRP: C-Reactive protein. Values are given as mean±standard deviation or median (25th–75th percentile).
Right eye involvement was higher in patients aged ≤five years (p=0.004), and left eye involvement was higher in patients aged >five years (p<0.001). Predisposing factors did not differ significantly between groups. When laboratory parameters were compared between groups, patients aged ≤five years had higher lymphocyte levels (p<0.001) but lower neutrophil levels (p<0.001), hemoglobin levels (p=0.002), and neutrophil-lymphocyte ratios (p<0.001).
Total treatment times were nonsignificantly longer for patients aged >five years (p=0.068). The time to clinical improvement was shorter in patients aged ≤five than >five years (4.4±1.6 vs. 5.6±2.5 days, p=0.005).
Evaluation of Factors Affecting the Duration of Treatment
Treatment durations were longer in patients with than without leukocytosis (9.3±3.1 vs. 7.8±2.5 days, p=0.009). However, no significant relationships existed between demographic and clinical characteristics and total treatment time except for age and leukocytosis.
DISCUSSION
This study evaluated the demographic and clinical characteristics of children hospitalized for preseptal cellulitis and the factors affecting them. Its main results were: (i) eye swelling and redness were the most common complaints in patients with preseptal cellulitis, with ampicillin-sulbactam + clindamycin therapy sufficient to treat most cases; (ii) the time to clinical improvement was shorter in patients aged ≤five than >five years.
If preseptal cellulitis is not treated in time, it can rapidly progress and cause complications such as orbital cellulitis, vision loss, subperiosteal abscess, orbital abscess, and cavernous sinus thrombosis. Its most common causes are sinusitis, local trauma, insect bites, tooth abscesses, and middle ear infections [8, 9]. In our study, the most common causes were buccal and sinus infections and insect bites. Our study’s low frequency of insect bites is likely because younger children may not have noticed them.
Preseptal cellulitis is frequently observed in boys and those aged ≤five years. It is frequently observed in this age group due to their lack of hygiene and sensitivity to infection [10–12]. It often develops due to sinusitis, insect bites, and foreign bodies. Therefore, unilateral involvement is often seen. Diseases such as angioedema and nephrotic syndrome should be considered in the differential diagnosis of bilateral involvement [11–13]. In our study, male patients aged ≤five years were also frequent. Bilateral involvement was observed only in 7.9%.
Patients with preseptal cellulitis commonly have infection findings, such as swelling of the eyes, erythema, and purulent discharge. This condition arises due to the causes and inflammation associated with preseptal cellulitis [10, 14]. Preseptal cellulitis incidence increases in spring due to increased insect bites and conjunctivitis [6, 14, 15]. In our study, eyelid swelling (100%) and erythema (80.2%) were the most common findings. In addition, it was observed frequently in winter and spring, possibly due to climatic conditions and the coronavirus disease 2019 (COVID-19) pandemic. Comprehensive prospective studies on this subject are needed.
Adding teicoplanin or clindamycin to ampicillin-sulbactam or ceftriaxone is recommended for treatment. The duration of antibiotic therapy is as important as the antibiotics [10, 11]. Treatment for 5–7 days is sufficient, but if cellulitis symptoms persist, it should be extended until erythema and swelling subside [16, 17]. Many studies reported intravenous treatment durations of 4–6 days and positive results with outpatient intravenous treatment [14, 17–19]. We added teicoplanin to patients showing no clinical improvement after 48 hours of treatment and acyclovir to patients with the herpes virus. In our study, the total treatment duration was 8.42±2.89 days, and the time to clinical improvement was 5.01±2.20 days, longer than in other studies. It is believed that the patients’ low socioeconomic level and poor personal hygiene affect this situation. In our study, the time to clinical improvement was longer in patients aged >five than ≤five years (4.4±1.6 vs. 5.6±2.5 days, p=0.005). Since sinusitis is high as a predisposing factor in this age group, it may have affected the time to clinical recovery.
While lymphocytosis develops in infections in children aged ≤five years, neutrophil levels increase after age five [20, 21]. Therefore, lymphocyte and neutrophil levels differed between age groups. The frequencies of physiological anemia and anemia are higher in children aged ≤five years compared to other age groups [21–23]. We found low hemoglobin levels in this age group. In addition, we found longer treatment durations for patients with leukocytosis. However, no significant relationship was found between leukocytosis and the time to clinical improvement. While the time to clinical improvement does not change, treatment prolongation can be explained by the serious approach to these patients since pediatricians in our clinic want to provide in-hospital intravenous treatment until leukocytosis is resolved.
In our study, no complications developed in patients treated for preseptal cellulitis. Their early diagnosis and adequate treatment prevented complications.
Limitations
Since most preseptal cellulitis patients were treated as outpatients with oral antibiotic therapy, the relatively small number of patients treated with hospitalization is a limitation of our study. Another limitation is its retrospective and single-center design. In addition, its lack of a control group can be considered a limitation.
Conclusions
The most common finding in the patients was swelling in the eye. Age was important in determining the patients’ time to clinical improvement. The presence of leukocytosis in patients could be used to predict treatment duration. Inadequate treatment of preseptal cellulitis may lead to serious complications. Early diagnosis and adequate treatment with antibiotics are required to prevent complications.
Footnotes
Cite this article as: Okay B, Dogan Kalinbacoglu C, Akkoc G, Hatipoglu HU, Dogan O, Sahin K, Buyukkayhan D. Evaluating hospitalized children for preseptal cellulitis: A single-center experience and current literature review. North Clin Istanb 2025;12(1):89–94.
Ethics Committee Approval
The Haseki Training and Research Hospital Clinical Research Ethics Committee granted approval for this study (date: 11.05.2022, number: 85-2022).
Authorship Contributions
Concept – BO, GA, HUH; Design – GA, CDK, OD, KS; Supervision – HUH, KS, DB; Data collection and/or processing – BO, CDK, OD, DB; Analysis and/or interpretation – BO, GA, KS, DB; Literature review – BO, CKD, OD, GA; Writing – BO, CKD, OD, DB; Critical review – GA, HUH, KS, OD.
Conflict of Interest
No conflict of interest was declared by the authors.
Use of AI for Writing Assistance
Not declared.
Financial Disclosure
The authors declared that this study has received no financial support.
Peer-review
Externally peer-reviewed.
References
- 1.Chaudhry IA, Shamsi FA, Elzaridi E, Al-Rashed W, Al-Amri A, Al-Anezi F, et al. Outcome of treated orbital cellulitis in a tertiary eye care center in the middle East. Ophthalmology. 2007;114:345–54. doi: 10.1016/j.ophtha.2006.07.059. [DOI] [PubMed] [Google Scholar]
- 2.Ambati BK, Ambati J, Azar N, Stratton L, Schmidt EV. Periorbital and orbital cellulitis before and after the advent of Haemophilus influenzae type B vaccination. Ophthalmology. 2000;107:1450–3. doi: 10.1016/S0161-6420(00)00178-0. [DOI] [PubMed] [Google Scholar]
- 3.Hauser A, Fogarasi S. Periorbital and orbital cellulitis. Pediatr Rev. 2010;31:242–9. doi: 10.1542/pir.31.6.242. [DOI] [PubMed] [Google Scholar]
- 4.Bae C, Bourget D. StatPearls. Treasure Island (FL): StatPearls Publishing; 2024. Periorbital Cellulitis. [Google Scholar]
- 5.Seltz LB, Smith J, Durairaj VD, Enzenauer R, Todd J. Microbiology and antibiotic management of orbital cellulitis. Pediatrics. 2011;127:e566–72. doi: 10.1542/peds.2010-2117. [DOI] [PubMed] [Google Scholar]
- 6.Miranda-Barrios J, Bravo-Queipo-de-Llano B, Baquero-Artigao F, Granados-Fernandez M, Noval S, Rabanal I, et al. Preseptal versus orbital cellulitis in children: an observational study. Pediatr Infect Dis J. 2021;40:969–74. doi: 10.1097/INF.0000000000003226. [DOI] [PubMed] [Google Scholar]
- 7.Orkin SH, Nathan DG, Ginsburg D, Look AT, Fisher DE, Lux S. Philadelphia: Saunders; 2015. Nathan and Oski’s hematology of infancy and childhood. [Google Scholar]
- 8.Smith TF, O’Day D, Wright PF. Clinical implications of preseptal (periorbital) cellulitis in childhood. Pediatrics. 1978;62:1006–9. doi: 10.1542/peds.62.6.1006. [DOI] [PubMed] [Google Scholar]
- 9.Babar TF, Zaman M, Khan MN, Khan MD. Risk factors of preseptal and orbital cellulitis. J Coll Physicians Surg Pak. 2009;19:39–42. [PubMed] [Google Scholar]
- 10.Bülbül L, Özkul Sağlam N, Kara Elitok G, Mine Yazici Z, Hatipoglu N, Hatipoğlu S, et al. Preseptal and orbital cellulitis: analysis of clinical, laboratory and imaging findings of 123 pediatric cases from Turkey. Pediatr Infect Dis J. 2022;41:97–101. doi: 10.1097/INF.0000000000003382. [DOI] [PubMed] [Google Scholar]
- 11.Gonçalves R, Menezes C, Machado R, Ribeiro I, Lemos JA. Periorbital cellulitis in children: analysis of outcome of intravenous antibiotic therapy. Orbit. 2016;35:175–80. doi: 10.1080/01676830.2016.1176205. [DOI] [PubMed] [Google Scholar]
- 12.Berk AT, Ayhan Z, Yaman A, Ecevit C. Diagnosis and treatment of preseptal cellulitis in pediatric age group. [Article in Turkish]. Turk J Orhthalmol. 2010;40:227–31. doi: 10.4274/tod.40.227. [DOI] [Google Scholar]
- 13.Lahmini W, Oumou M, Bourrous M. Management of periorbital cellulitis at the pediatric emergency department: a ten years study. J Fr Ophtalmol. 2022;45:166–72. doi: 10.1016/j.jfo.2021.09.012. [DOI] [PubMed] [Google Scholar]
- 14.Santos JC, Pinto S, Ferreira S, Maia C, Alves S, da Silva V. Pediatric preseptal and orbital cellulitis: a 10-year experience. Int J Pediatr Otorhinolaryngol. 2019;120:82–8. doi: 10.1016/j.ijporl.2019.02.003. [DOI] [PubMed] [Google Scholar]
- 15.Öcal Demir S, Çağan E, Kepenekli Kadayıfçı E, Karaaslan A, Atıcı S, Akkoç G, et al. Clinical features and outcome of preseptal and orbital cellulitis in hospitalized children: four years experience. Medeniyet Med J. 2017;32:7–13. doi: 10.5222/MMJ.2017.007. [DOI] [Google Scholar]
- 16.Alexander AJ, Richardson SE, Sharma A, Campisi P. The increasing prevalence of clindamycin resistance in Staphylococcus aureus isolates in children with head and neck abscesses. Can J Infect Dis Med Microbiol. 2011;22:49–51. doi: 10.1155/2011/261519. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Howe L, Jones NS. Guidelines for the management of periorbital cellulitis/abscess. Clin Otolaryngol Allied Sci. 2004;29:725–8. doi: 10.1111/j.1365-2273.2004.00889.x. [DOI] [PubMed] [Google Scholar]
- 18.Tritt A, Kay-Rivest E, Paradis T, Duval M. Daily outpatient intravenous antibiotic therapy for the management of paediatric periorbital cellulitis, a retrospective case series. Clin Otolaryngol. 2019;44:273–8. doi: 10.1111/coa.13284. [DOI] [PubMed] [Google Scholar]
- 19.Brugha RE, Abrahamson E. Ambulatory intravenous antibiotic therapy for children with preseptal cellulitis. Pediatr Emerg Care. 2012;28:226–8. doi: 10.1097/PEC.0b013e318248b19b. [DOI] [PubMed] [Google Scholar]
- 20.Goldstein B, Giroir B, Randolph A. International Consensus Conference on Pediatric Sepsis. International pediatric sepsis consensus conference: definitions for sepsis and organ dysfunction in pediatrics. Pediatr Crit Care Med. 2005;6:2–8. doi: 10.1097/01.PCC.0000149131.72248.E6. [DOI] [PubMed] [Google Scholar]
- 21.Gallagher PG. The neonatal erythrocyte and its disorders. In: Orkin SH, Fisher DE, Look T, Lux SE, Ginsburg D, Nathan DG, editors. Nathan and Oski’s Hematology and Oncology of Infancy and Childhood. Philadelphia: WB Saunders; 2015. p. 52. [Google Scholar]
- 22.WHO Worldwide prevalence of anaemia 1993-2005. Available at: https://iris.who.int/bitstream/handle/10665/43894/9789241596657_eng.pdf?sequence=1&isAllowed=y. Accessed Sept 13, 2024.
- 23.Moosmann J, Krusemark A, Dittrich S, Ammer T, Rauh M, Woelfle J, et al. Age-and sex-specific pediatric reference intervals for neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio. Int J Lab Hematol. 2022;44:296–301. doi: 10.1111/ijlh.13768. [DOI] [PubMed] [Google Scholar]