Abstract
Purpose
In the ‘Itch-Scratch cycle’, scratching manifests in various ways and further provokes skin inflammation and alteration of the skin microbiota. However, there is an unmet demand for classifying and interpreting scratching behavior. We analyze patterns of scratching behavior expressed by patients with chronic pruritus.
Methods
A survey was conducted on 206 adult patients with chronic pruritus for more than six weeks. Participants responded to a questionnaire about pruritus, including standard unidimensional-scale questions, as well as individualistic questions about sensory expression and quality of life. For scratching behavior, all patients answered questions about patterns, tools, situations, time spent, and scratched areas. Exploratory factor analysis was conducted to classify scratching behavior. Descriptive and exploratory factor analyses were used to identify the structure of the underlying factors measured by the questionnaire items.
Results
Among pruritic descriptors, ‘unbearable’ was the most common (84.5%). Of 206 participants, 190 (92.2%) responded that they scratched. The most common itch resolution methods were ‘applying moisturizer’, ‘rubbing’, and ‘applying ointment’. The fingernails (89.3%) were the most frequently reported tool used for scratching. Participants reported most frequent scratching during sleep or rest. Among the pruritus-specific quality-of-life indicators, ‘Lifelong’ was the most stressful item related to all scratching behaviors. Regarding scratching differences by disease, patients with prurigo showed shorter scratching time with abnormal and aggressive behavior.
Conclusions
We analyzed scratching behavior patterns in patients with chronic pruritus. Our findings support the need for education on the importance of applying moisturizer before sleep. The results are also important for helping patients with prurigo correct their abnormal and aggressive scratching behavior patterns, which can reduce quality of life and worsen symptoms.
Keywords: Compulsive behavior, pruritus, skin
INTRODUCTION
Pruritus is defined as an unpleasant sensation that triggers the urge to scratch; this sensation manifests as a prevalent symptom in various conditions.1,2,3 Due to its subjective and multifactorial nature, pruritus manifests in various forms, and patients describe it in diverse ways.4 Given these characteristics, assessing pruritus can be challenging, and many assessment methods have been developed using multiple instruments.5,6
Pruritus is interconnected to scratching through the ‘itch-scratch cycle’ that describes progressively exacerbating skin conditions.7 Scratching behavior causes physical damage to the skin and provokes additional skin inflammation and altered skin microbiota.8,9 Scratching behavior can also manifest differently among patients and among encompassing various ways of stimulating the skin beyond mere ‘scratching’. Despite the dermatologic importance of scratching behavior, attempts to systematically classify and interpret it remain scarce.
Considering the diverse clinical features of pruritus and scratching behavior, as well as the well-established correlation between the two, accurately identifying the expressions of pruritus and scratching behavior is crucial for effective treatment. Although various questionnaires have been developed to measure pruritus-related characteristics, clinical evaluation predominantly relies on the intensity of symptoms, which is measured through tools like the numeric rating scale, visual analog scale (VAS), and verbal rating scale.10 Nevertheless, because a unidimensional scale cannot effectively describe the individualized and specific characteristics of pruritus, additional analysis of individual pruritus expression is necessary. In previous work, we categorized pruritus descriptions in patients with chronic pruritus as either sensory or affective.11 Patients who used affective descriptors, such as ‘annoying,’ ‘unbearable,’ ‘worrisome,’ and ‘warm’, reported poorer quality of life (QoL) than those who used sensory descriptors including ‘stinging,’ ‘stabbing,’ ‘burning,’ ‘pain,’ ‘formication,’ ‘throbbing,’ and ‘cold.’ The result showed a relationship between descriptions of pruritus and QoL.
Despite gaining a deeper understanding of pruritus expression, methods for individually modulating expression remain limited in clinical settings. Further analyzing the characteristics of pruritus and identifying modifiable scratching behaviors are important to effectively interrupt the itch-scratch cycle. This study aimed to examine the characteristics of scratching behavior in patients with various types of chronic pruritus and to explore differences in scratching behaviors among these patients through a multicenter, questionnaire-based analysis, as shown in categorization of pruritic descriptions.11
MATERIALS AND METHODS
Study design and sample
This cross-sectional multicenter survey on scratching behavior was conducted in four hospitals in Korea from October 2022 to August 2023. A total of 206 patients (aged ≥ 19 years) who presented with chronic (> 6 weeks) pruritus, regardless of cause, were enrolled. The study protocol complied with the principles of the Declaration of Helsinki and was approved by the Institutional Review Board (IRB) of Kyungpook National University Hospital, Daegu, Republic of Korea (IRB number KNUH 2022-09-001).
Survey instrument
Core experts developed the survey on scratching behavior through drafting, feedback revisions, final review, and editing (Fig. 1). Multidimensional investigations were conducted to analyze characteristics of scratching behaviors, including the tools used, situations, durations, and locations. The full survey instrument is provided in Supplementary Data S1. The causes of itching were categorized into dermatologic and non-dermatologic causes. Subsequently, dermatologic causes were further classified into four subcategories: “Atopic dermatitis (AD, Group 1)”, “Prurigo (Group 2)”, “Eczema other than AD (Group 3)”, and “Others (Group 4).” Prurigo nodularis (PN) and essential pruritus were grouped under the “Group 2” category. “Group 3” category encompassed eczema occurring on various parts of the body, including the trunk, nipples, extremities, and hands. The “Group 4” category included other skin diseases that can cause itching, such as symptomatic dermographism, other forms of urticaria, xerosis cutis, lichen simplex chronicus.
Fig. 1. Case report form: (A) Questionnaire including a unidimensional itch scale, scratching behaviors, and scratching characteristics (tools, situations, time, area) and (B) scratching behaviors (left) and questions about the quality of life of patients with chronic pruritus (right).
Subjects were allowed to select anywhere from a single answer to all available options. By not restricting the number of responses, we aimed to analyze all of the various scratching patterns expressed by patients.
Statistical analysis
To identify the structure of the underlying factors measured by questionnaire items related to scratching behaviors, factor analyses were conducted. After exploring factor structures of scratching behaviors using an exploratory factor analysis (EFA),12 we confirmed the factor structure through a confirmatory factor analysis (CFA). In addition, we examined relationships among the other characteristics, such as patient disease, and pruritus characteristics and scratching behaviors, by using analysis of variance (ANOVA).
RESULTS
Demographics and pruritus characteristics
Of the 206 patients included in the study, 116 (56.3%) were male with a mean age of 40.0 years (SD = 17.2). Among these patients, 66.0% presented with generalized pruritus. The etiology of pruritus was predominantly dermatologic (98.1%), with AD (Group 1) being the most common diagnosis affecting 41.3% of the total patients. In total, 72.8% of patients were prescribed antipruritic medications, but only 40.0% of them reported sustained relief (Table 1). Mean pruritus intensity, measured using the VAS, was 5.3 (SD = 2.7) on a 0–10-point scale (Supplementary Table S1).
Table 1. Clinical characteristics of patients with chronic pruritus.
| Characteristics | Values | ||
|---|---|---|---|
| Total | 206 | ||
| Sex | |||
| Male | 116 (56.3) | ||
| Female | 90 (43.6) | ||
| Age (yr) | 40 ± 17.2 | ||
| Duration (onset to first visit) (wk) | 371.17 ± 498 | ||
| Past history | |||
| Hypertension | 31 (15.0) | ||
| Diabetes | 18 (8.7) | ||
| Tuberculosis | 0 (0.0) | ||
| Kidney disease | 2 (1.0) | ||
| Liver disease | 4 (1.9) | ||
| Thyroid disease | 4 (1.9) | ||
| Other systemic disease | 33 (16.0) | ||
| Distribution of pruritus | |||
| Localized | 71 (34.0) | ||
| Generalized | 135 (66.0) | ||
| Etiology of pruritus | |||
| Dermatologic pruritus | 202 (98.1) | ||
| Atopic dermatitis (Group 1) | 85 (41.3) | ||
| Prurigo (Group 2) | 20 (9.7) | ||
| Eczema, other than AD (Group 3) | 28 (13.6) | ||
| Others (Group 4) | 69 (33.5) | ||
| Non-dermatologic pruritus | 4 (1.9) | ||
| Antipruritic medication use | |||
| Yes | 150 (72.8) | ||
| Sustained medication effect | 60 (29.1) | ||
| Temporary medication effect | 81 (39.3) | ||
| No medication effect | 9 (4.4) | ||
| No | 56 (27.2) | ||
| Other medication use | |||
| Other daily medication | 75 (36.4) | ||
| Other intermittent medication | 28 (13.6) | ||
| Other herb medication | 7 (3.4) | ||
Values are presented as mean ± standard deviation or as number (%).
Behavior patterns of pruritus and scratching
Various scratching behaviors were employed by the patients to characterize their pruritus sensations. Among these, ‘unbearable’ was the most commonly reported feeling (84.5%) of patients, followed by annoying (75.2%). Among all enrolled patients, 92.2% reported scratching due to chronic pruritus. Applying moisturizer, rubbing, and applying ointment were reported by 77.7%, 71.8%, and 70.4% of patients, respectively (Table 2).
Table 2. Summary of pruritus and scratching behaviors for 206 patients with chronic pruritus.
| Variables | Values | ||
|---|---|---|---|
| Pruritus | |||
| Pruritus descriptors | |||
| Unbearable | 174 (84.5) | ||
| Annoying | 155 (75.2) | ||
| Stinging | 139 (67.5) | ||
| Warm | 133 (64.6) | ||
| Worrisome | 131 (63.6) | ||
| Formication | 117 (56.8) | ||
| Painful | 67 (32.5) | ||
| Throbbing | 67 (32.5) | ||
| Burning | 56 (27.2) | ||
| Stabbing | 44 (21.4) | ||
| Cold | 12 (5.8) | ||
| Scratching | |||
| Scratching behavior | |||
| Yes | 190 (92.2) | ||
| No | 16 (7.8) | ||
| Scratching descriptors | |||
| Applying moisturizer | 160 (77.7) | ||
| Rubbing | 148 (71.8) | ||
| Applying ointment | 145 (70.4) | ||
| Enduring | 132 (64.1) | ||
| Stroking | 122 (59.2) | ||
| Pressing | 115 (55.8) | ||
| Wind | 112 (54.4) | ||
| Cooling | 110 (53.4) | ||
| Cold shower | 102 (49.5) | ||
| Bleeding | 94 (45.6) | ||
| Hot shower | 91 (44.2) | ||
| Distraction | 90 (43.7) | ||
| Cutting | 89 (43.2) | ||
| Pinching | 81 (39.3) | ||
| Scraping | 78 (37.9) | ||
| Lancing | 75 (36.4) | ||
| Kneading | 71 (34.5) | ||
| Squeezing | 69 (33.5) | ||
| Digging/Gouging | 48 (23.3) | ||
| Biting | 40 (19.4) | ||
| Heating | 27 (13.1) | ||
| Moxibustion | 25 (12.1) | ||
| Others | 12 (5.8) | ||
| Bath | 9 (4.4) | ||
Values are presented as number (%).
Factor analyses were employed to explore the correlations among scratching behavior items and to identify clusters that characterize heterogeneous scratching behaviors. EFA revealed four clusters of scratching behaviors and, then, CFA exhibited variations in intensity and atypical behavior patterns thereof (Fig. 2). Factor 1, which included behaviors such as ‘Applying moisturizer’ and ‘Applying ointment’ represented the most easily accessible approaches for managing pruritus. Factors 2 and 3 represented more severe scratching behaviors than factor 1. Factor 4 reported excessive and visually satisfying actions potentially driven by abnormal psychogenic motivations. All factor loadings were greater than 0.5, except ‘Moxibustion’ (0.287) and ‘Heating’ (0.233) and all factor correlations were less than 0.6, indicating that the factor structure confirmed by CFA maintained both convergent and divergent validities. These validities confirm that the four factors are well defined and distinguishable. We also analyzed mean differences among factors using ANOVA, comparing categorical variables (classified diseases) and continuous variables (four factors). Only factor 1 showed significant differences across classified diseases. Regarding factor 1 (applying moisturizer and applying ointment), the Groups 1 and 3 applied moisturizers significantly more than the Groups 2 and 4. This may be due to the fact that AD, as well as other eczema lesions, are often accompanied by skin dryness.
Fig. 2. Exploratory and confirmatory factor analysis of scratching behavior items and factor loadings.
RMSEA, root mean square error of approximation; CI, confidence interval; CFI, comparative fit index; TLI, Tucker–Lewis index; SRMR, standardized root mean square residual.
Characteristics of scratching behavior
Regarding the tools utilized for scratching, fingernails were the most common (n = 184 patients; 89.3%). Most patients reported scratching while lying in bed (67.5%) and while sleeping (54.4%). When asked about the duration of scratching episodes, 36.9% reported spending less than half an hour scratching per day, while 14.1% reported scratching for one to three hours or constantly throughout the day. Scratching predominantly targeted specific areas of the body (Table 3).
Table 3. Characteristics of scratching behaviors in patients with chronic pruritus.
| Characteristics | Values | ||
|---|---|---|---|
| Total | 206 | ||
| What kind of tool do you use? | |||
| Fingernails | 184 (89.3) | ||
| Fingers | 106 (51.5) | ||
| Scratchers | 33 (16.0) | ||
| Toenails | 19 (9.2) | ||
| Toes | 12 (5.8) | ||
| Tissues | 10 (4.9) | ||
| Teeth | 6 (2.9) | ||
| Pins | 4 (1.9) | ||
| Scissors | 2 (1.0) | ||
| Tweezers | 2 (1.0) | ||
| Others | 9 (4.4) | ||
| What kind of situation is most common for scratching? | |||
| While lying in bed | 139 (67.5) | ||
| While sleeping | 112 (54.4) | ||
| At rest | 106 (51.5) | ||
| In the morning | 79 (38.3) | ||
| At work | 72 (35.0) | ||
| While watching TV | 50 (24.3) | ||
| While taking a shower | 38 (18.4) | ||
| While driving | 24 (11.7) | ||
| Other situations | 21 (10.2) | ||
| How many hours of your day do you spend scratching? | |||
| < 0.5 hr | 76 (36.9) | ||
| 0.5–1 hr | 49 (23.8) | ||
| 1–3 hr | 29 (14.1) | ||
| 3–12 hr | 23 (11.2) | ||
| All the time | 29 (14.1) | ||
| Which area of your body do you usually scratch? | |||
| Head and neck | 106 (51.5)/84 (40.8) | ||
| Chest | 100 (48.5)/123 (59.7) | ||
| Abdomen | 90 (43.7)/105 (51.0) | ||
| Upper extremities | |||
| Rt hand | 136 (66.0)/89 (43.2) | ||
| Lt hand | 133 (64.6)/98 (47.6) | ||
| Lower extremities | |||
| Rt leg | 129 (62.6)/125 (60.7) | ||
| Lt leg | 126 (61.2)/127 (61.7) | ||
| Anogenital | 51 (24.8)/35 (17.0) | ||
Values are presented as number (%).
Analysis of scratching behavior according to pruritus descriptors
As described in our previous study,11 sensory and affective pruritus groups showed different QoL; thus, in this study, we compared scratching behaviors within each item level. As a specific behavior for managing pruritus, ‘applying moisturizer’ was the most common method of alleviation among the itching items. However, patients’ responses in the affective pruritus items typically indicated scratching for less than half an hour. In contrast, those with sensory pruritus items exhibited a variety of scratching duration, but the proportion of patients who scratched all the time was higher.
When analyzing QoL according to pruritus descriptors, 8 of 11 descriptors (‘stinging,’ ‘stabbing,’ ‘pain,’ ‘formication,’ ‘throbbing,’ ‘cold,’ ‘unbearable,’ ‘warm’) were associated with “obligation,” indicating that the patients felt compelled to scratch when they experienced pruritus. Additionally, when evaluating the decrease in QoL of the patients due to pruritus, 9 of 11 pruritus descriptors (‘stinging,’ ‘burning,’ ‘annoying,’ ‘unbearable,’ ‘worrisome,’ ‘pain,’ ‘formication,’ ‘throbbing,’ ‘warm’) showed the largest decrease in QoL and were associated with lifelong pruritus, which was patients’ most significant concern (Supplementary Table S2).13
Analysis of pruritus-specific QoL according to scratching
The potential experience of lifelong pruritus was the most significant concern among all responding patients. When considering the intensity based on the mean score of ItchyQoL according to scratching behaviors, “lifelong” indicated high apprehension about lifelong pruritus and was consistently ranked as the most significant among the 21 scratching behaviors (Supplementary Table S3). Moreover, ‘temperature,’ ‘soap,’ ‘obligation,’ and ‘disappointment’ were considerable factors affecting QoL in patients with chronic pruritus (Supplementary Table S3).
Patterns of pruritus and scratching according to patient clinical characteristics
Pruritus patterns according to the clinical characteristics of the included patients with chronic pruritus are reported in Supplementary Table S4. ‘Unbearable’ and ‘applying moisturizer’ were the most common pruritus and scratching behaviors, respectively, regardless of sex, age, duration, and distribution.
Analysis patterns of pruritus and scratching according to dermatologic disease
Across the spectrum of dermatologic diseases under investigation, the pruritus severity scale, which is based on a unidimensional scale, was slightly lower in AD compared with prurigo, eczema other than AD, and other (Supplementary Table S5). This result highlights the differences in itch severity, emphasizing PN and eczema’s more intense and persistent itch compared to AD. Although the survey did not explicitly indicate whether AD patients were in a pre-treatment or treatment phase, the high proportion of patients (72.8%) on antipruritic medications suggests a mix of treatment states. The emergence of targeted therapies, such as dupilumab and Janus kinase inhibitors, has notably improved AD management. In contrast, PN and eczema remain challenging to treat due to their less understood etiologies and limited therapeutic responses, which likely influenced the observed differences in itch severity.
When categorizing pruritus descriptors into two groups,11 affective pruritus items consistently ranked high across all dermatologic disease groups. Patients with eczema, including AD, exhibited a heightened propensity for experiencing a warm sensation. Moisturizers (45.0%) or ointments (55.0%) were used less frequently by patients with prurigo (Supplementary Table S6).
Seventy percent of patients with prurigo scratched for less than an hour, a higher proportion than among patients with AD and other eczema. Patients with AD exhibited significantly more frequent pruritus in the head and neck area than patients with other dermatologic diseases. Anogenital scratching was less common but was still reported by a notable proportion of patients across dermatologic conditions (Supplementary Table S7).
DISCUSSION
The subjective and multidimensional nature of pruritus has prompted extensive research to understand its impact on patients.14,15,16 Numerous studies have operationalized scratching behaviors and assessed pruritus-specific QoL across various medical conditions, aiming to evaluate different dimensions of pruritus and to enhance patient care while improving overall QoL.17,18,19,20,21,22,23
Beyond this, our focus has shifted to the practical behavior of scratching, which is a direct manifestation of the itch-scratch cycle. As is well known, intense scratching affects both the epidermal and dermal layers, weakening the skin’s protective barrier and triggering the production of pro-inflammatory cytokines, which aggravate inflammation. Convincing evidence suggests that minimizing scratching can mitigate the inflammatory response, potentially offering therapeutic benefits.8 Furthermore, these physical disruptions may also alter the skin microbiota, which contribute to skin repair processes in varying ways, as the microbes can either promote or delay skin healing.9 Because scratching behavior is more objectively observable than pruritus, it could provide methods for assessing the severity and specific manner of scratching. Furthermore, directly observing patients’ coping mechanisms for relieving pruritus allows us to guide corrective measures. Consequently, our study aimed to present and categorize patient behavioral patterns related to scratching behaviors by examining the differences across various factors (such as patient characteristics, situational context, and pruritus-provoking diseases). By categorizing scratching behaviors and identifying which actions have a more detrimental impact on pruritus-specific QoL, we anticipate offering alternative pruritus management strategies and corrective interventions for patients.
In this study, according to classification into four factors based on the highly correlated scratching behaviors using EFA and CFA, factors 2 and 3 exhibited more severe scratching behaviors than factor 1. In particular, the behaviors included in factor 4 may lead to severe skin damage and exacerbate the itch-scratch cycle. Because scratching behavior could be classified by intensity of damage to the skin, patients displaying high-intensity scratching behavior to alleviate pruritus might also perform other high-intensity scratching behaviors, exacerbating the itch-scratch cycle. Hence, it is imperative to help patients replace high-intensity scratching behaviors with milder alternatives through education.
In this study, more than 90% of patients experienced scratching and used different behavioral patterns to mitigate pruritus (Table 2). Notably, frequent application of moisturizers or ointments played a significant role in pruritus management. Patients consistently used moisturizers in addition to their medications. This behavior would have benefited from education about moisturizer use, which would have served two crucial purposes: breaking the itch-scratch cycle and strengthening the skin-barrier function. Proper education, especially for those who have high-intensity scratching behavior, is paramount.
Patients also took steps to reduce itching: 50% used methods to reduce the surface temperature of their skin, such as cooling, cold showers, or exposure to wind. Cooling interventions can activate antipruritic pathways through dorsal root ganglion neurons with transient receptor potential cation channel subfamily M member 8 (TRPM-8) in the spinal cord to mediate a cooling perception. These neurons form synapses with inhibitory B5-1 neurons in the dorsal horn, affecting pruriceptor neurons via the gastrin-related peptide receptor pathway.24,25 In this context, it is understandable that cooling interventions were observed to alleviate pruritus. Thus, products utilizing TRPM-8 agonists have been developed.26 Despite the absence of direct evidence on this matter, many patients with chronic pruritus have independently adopted cooling for itch relief.
Our study observed that more than 50% of patients experience pruritus, mainly when they were lying in bed, sleeping, or at rest, indicating a general pattern of exacerbation during periods of inactivity. During non-rapid eye movement sleep, the hypothalamic temperature set point decreases, leading to peripheral vessel vasodilation and increased cutaneous blood flow, promoting heat dissipation. The resulting elevated skin surface temperature is correlated with a heightened perception of pruritus.27,28,29 Furthermore, alterations in skin barrier function occur during sleep. Notably, trans-epidermal water loss increases in the evening, contributing to skin dryness and exacerbating pruritus.30 Moreover, distractions such as audiovisual stimuli or noise are known to profoundly impact and reduce pruritus perception.31 When attention to pruritus is diverted by work-related tasks, relatively fewer scratching behaviors are observed. Conversely, increased focus on pruritus likely leads to more frequent scratching behavior during rest after work hours.
As an extension of our previous study, we observed a lower frequency of scratching behavior in the affective pruritus group (93.1% to 96.2%) than in the sensory pruritus group (95.5% to 100%). Moreover, patients with affective pruritus tended to scratch for less than half an hour, while those with sensory pruritus generally scratched all the time. In contrast to our initial expectations that patients who scratched all day would have a lower QoL, patients in the affective pruritus group, which was associated with a poorer QoL, spent a relatively shorter scratching time than those in the sensory pruritus group. Therefore, we hypothesized that, even for a brief period, sudden and unpredictable pruritus can significantly impact QoL. Moreover, individuals who engage in prolonged scratching may paradoxically experience stress relief from scratching. Consequently, those who scratch less may be more susceptible to this stress. These characteristics, including the unpredictable nature of pruritus and pleasure in scratching, influence the QoL as much as the intensity of pruritus.
In our study, the ItchyQoL13 was investigated in patients with chronic pruritus, and the frequencies of use of ‘lifelong’ and ‘obligation’ indicated their influence (Supplementary Table S2). The original version of the ItchyQoL questionnaire in the United States delineated three domains: symptoms (items 1–6), functioning (items 7–13), and emotions (items 14–22).13 Notably, the domain related to emotions exhibited the strongest association with patient concerns of chronic pruritus. Apprehension about lifelong pruritus played a pivotal role in diminishing patients’ overall QoL. Considering these findings, we recommend a targeted approach that emphasizes reassurance and addresses both persistent pruritus and its potential recurrence within clinical contexts. By fostering a shift in perception and implementing effective management strategies, clinicians can enhance patient outcomes and alleviate the burden of chronic itching. There was no significant difference in ItchyQoL scores based on scratching behavior.
When categorized by disease, we identified distinct variations in patterns of scratching behavior. Patients with prurigo showed a distinct pattern of clinical presentations compared with those with eczema, including AD. Rubbing behavior showed a relatively low incidence, while patients with prurigo demonstrated a relatively higher proportion of ‘digging/gouging’ ‘cutting,’ and ‘moxibustion’ than those with other dermatologic diseases. This observation suggests the presence of unique skin lesion characteristics of patients with prurigo who may not find relief through common scratching. Patients with prurigo have an increased tendency for more severe and aberrant behaviors that offer visual satisfaction. Furthermore, when analyzing scratching duration across conditions, patients with prurigo were more likely to engage in scratching for less than one hour than those with eczema, including AD. As previously mentioned, a shorter scratching duration may be more pronounced in affective pruritus, where it adversely impacts ItchyQoL.11 Consequently, we speculate that patients with prurigo might have worse overall ItchyQoL scores.
This study has several limitations. First, there may be a selection bias to acknowledge, as patients visiting university hospitals may have engaged in more intense or abnormal scratching behavior than the general population, or they may experience heightened anxiety due to pruritus refractory to standard therapies. Secondly, the use of multidimensional scales could be susceptible to recall bias compared with the use of intuitive unidimensional scales. Thirdly, despite the robust multicenter design, all the participants were only from Korean hospitals. It may be difficult to apply these results to other countries because the subjective pruritus descriptors used in this study can have affective implications depending on linguistic differences, and among the scratch behaviors presented in our study, moxibustion is a factor that may be affected by cultural differences. Therefore, it is important to conduct further research involving patients with chronic pruritus from wider populations to enhance our understanding of this issue.
This study provides valuable insights into the specific characteristics of scratching behaviors and their correlation with QoL. Mild and protective methods for alleviating pruritus were frequently used by patients in our study. Moreover, patients spontaneously found methods to diminish pruritus by adjusting their skin temperature, a well-established antipruritic strategy. Because patients tend to experience increased scratching during rest or sleep, applying moisturizer before resting or sleeping may help alleviate pruritus severity and diminish scratching. Patients who scratched for less than half an hour tended to describe their pruritus using affective scratching behaviors, suggesting a possible association with poorer QoL. Regarding QoL, the emotional domain was highly deteriorated by chronic pruritus. In clinical settings, it can be inferred that the shorter time and sudden occurrence of scratching behavior have a more significant impact on QoL than disease duration or pattern of scratching behavior. Therefore, it is necessary to investigate scratching behavior patterns and understand various disease dimensions to effectively address pruritus’ impact on patient well-being.
ACKNOWLEDGMENTS
This work was supported by the Technology Innovation Program (20023929) funded by the Ministry of Trade, Industry & Energy (MOTIE), Korea.
Footnotes
Disclosure: There are no financial or other issues that might lead to conflict of interest.
SUPPLEMENTARY MATERIALS
Survey Instrument
Summary of unidimensional itch intensity scale scores in the total 206 patients with chronic pruritus
Summary of scratching behaviors by pruritus descriptors
Summary of the ItchyQoL findings by scratching behaviors
Summary of pruritus descriptors by the clinical characteristics of the patients
Summary of unidimensional itch intensity scales in patients with dermatologic diseases
Summary of pruritus and scratching descriptors in patients with chronic pruritus
Characteristics of scratching behaviors in patients with dermatologic diseases
References
- 1.Roh YS, Choi J, Sutaria N, Kwatra SG. Itch: epidemiology, clinical presentation, and diagnostic workup. J Am Acad Dermatol. 2022;86:1–14. doi: 10.1016/j.jaad.2021.07.076. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Yonova D. Pruritus in certain internal diseases. Hippokratia. 2007;11:67–71. [PMC free article] [PubMed] [Google Scholar]
- 3.Ständer S, Weisshaar E, Mettang T, Szepietowski JC, Carstens E, Ikoma A, et al. Clinical classification of itch: a position paper of the International Forum for the Study of Itch. Acta Derm Venereol. 2007;87:291–294. doi: 10.2340/00015555-0305. [DOI] [PubMed] [Google Scholar]
- 4.Ständer S, Augustin M, Reich A, Blome C, Ebata T, Phan NQ, et al. Pruritus assessment in clinical trials: consensus recommendations from the International Forum for the Study of Itch (IFSI) Special Interest Group Scoring Itch in Clinical Trials. Acta Derm Venereol. 2013;93:509–514. doi: 10.2340/00015555-1620. [DOI] [PubMed] [Google Scholar]
- 5.Pereira MP, Ständer S. Assessment of severity and burden of pruritus. Allergol Int. 2017;66:3–7. doi: 10.1016/j.alit.2016.08.009. [DOI] [PubMed] [Google Scholar]
- 6.Dominick F, van Laarhoven AIM, Evers AWM, Weisshaar E. A systematic review of questionnaires on itch by the Special Interest Group “Questionnaires” of the International Forum for the Study of Itch (IFSI) Itch. 2019;4:e26 [Google Scholar]
- 7.Rinaldi G. The itch-scratch cycle: a review of the mechanisms. Dermatol Pract Concept. 2019;9:90–97. doi: 10.5826/dpc.0902a03. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Weisshaar E, Bentz P, Haufe E, Heinrich L, Apfelbacher C, Heratizadeh A, et al. Itching and treatments in atopic dermatitis (AD): results from the German AD registry TREATgermany. Br J Dermatol. 2023;188:430–432. doi: 10.1093/bjd/ljac070. [DOI] [PubMed] [Google Scholar]
- 9.Canchy L, Kerob D, Demessant A, Amici JM. Wound healing and microbiome, an unexpected relationship. J Eur Acad Dermatol Venereol. 2023;37(Suppl 3):7–15. doi: 10.1111/jdv.18854. [DOI] [PubMed] [Google Scholar]
- 10.Phan NQ, Blome C, Fritz F, Gerss J, Reich A, Ebata T, et al. Assessment of pruritus intensity: prospective study on validity and reliability of the visual analogue scale, numerical rating scale and verbal rating scale in 471 patients with chronic pruritus. Acta Derm Venereol. 2012;92:502–507. doi: 10.2340/00015555-1246. [DOI] [PubMed] [Google Scholar]
- 11.Ryoo JH, Lee SH, Ha DL, Park KD, Rho J, Park GH, et al. Validation of relationship between patients’ descriptions of pruritus and patient-burden of chronic pruritus using structural equation modelling. Acta Derm Venereol. 2022;102:adv00819. doi: 10.2340/actadv.v102.2527. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Pett MALN, Sullivan JJ. Making sense of factor analysis: the use of factor analysis for instrument development in health care research. Thousand Oaks (CA): Sage; 2003. [Google Scholar]
- 13.Desai NS, Poindexter GB, Monthrope YM, Bendeck SE, Swerlick RA, Chen SC. A pilot quality-of-life instrument for pruritus. J Am Acad Dermatol. 2008;59:234–244. doi: 10.1016/j.jaad.2008.04.006. [DOI] [PubMed] [Google Scholar]
- 14.Yosipovitch G, Zucker I, Boner G, Gafter U, Shapira Y, David M. A questionnaire for the assessment of pruritus: validation in uremic patients. Acta Derm Venereol. 2001;81:108–111. doi: 10.1080/00015550152384236. [DOI] [PubMed] [Google Scholar]
- 15.Rolader R, DeGrazia TM, Zhang C, Yosipovitch G, Chen SC, Yeung H. Factor analysis of subjective descriptors of chronic pruritus and association with quality of life: a cross-sectional survey. J Am Acad Dermatol. 2020;82:1519–1521. doi: 10.1016/j.jaad.2020.01.037. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Lee J, Suh H, Jung H, Park M, Ahn J. Association between chronic pruritus, depression, and insomnia: a cross-sectional study. JAAD Int. 2021;3:54–60. doi: 10.1016/j.jdin.2021.02.004. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Kini SP, DeLong LK, Veledar E, McKenzie-Brown AM, Schaufele M, Chen SC. The impact of pruritus on quality of life: the skin equivalent of pain. Arch Dermatol. 2011;147:1153–1156. doi: 10.1001/archdermatol.2011.178. [DOI] [PubMed] [Google Scholar]
- 18.Warlich B, Fritz F, Osada N, Bruland P, Stumpf A, Schneider G, et al. Health-related quality of life in chronic pruritus: an analysis related to disease etiology, clinical skin conditions and itch intensity. Dermatology. 2015;231:253–259. doi: 10.1159/000437206. [DOI] [PubMed] [Google Scholar]
- 19.Erturk IE, Arican O, Omurlu IK, Sut N. Effect of the pruritus on the quality of life: a preliminary study. Ann Dermatol. 2012;24:406–412. doi: 10.5021/ad.2012.24.4.406. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Kong TS, Han TY, Lee JH, Son SJ. Correlation between severity of atopic dermatitis and sleep quality in children and adults. Ann Dermatol. 2016;28:321–326. doi: 10.5021/ad.2016.28.3.321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Kaaz K, Szepietowski JC, Matusiak Ł. Influence of itch and pain on sleep quality in atopic dermatitis and psoriasis. Acta Derm Venereol. 2019;99:175–180. doi: 10.2340/00015555-3065. [DOI] [PubMed] [Google Scholar]
- 22.Sommer R, Augustin M, Hilbring C, Ständer S, Hubo M, Hutt HJ, et al. Significance of chronic pruritus for intrapersonal burden and interpersonal experiences of stigmatization and sexuality in patients with psoriasis. J Eur Acad Dermatol Venereol. 2021;35:1553–1561. doi: 10.1111/jdv.17188. [DOI] [PubMed] [Google Scholar]
- 23.Hawro T, Przybyłowicz K, Spindler M, Hawro M, Steć M, Altrichter S, et al. The characteristics and impact of pruritus in adult dermatology patients: a prospective, cross-sectional study. J Am Acad Dermatol. 2021;84:691–700. doi: 10.1016/j.jaad.2020.08.035. [DOI] [PubMed] [Google Scholar]
- 24.Liu B, Jordt SE. Cooling the Itch via TRPM8. J Invest Dermatol. 2018;138:1254–1256. doi: 10.1016/j.jid.2018.01.020. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Palkar R, Ongun S, Catich E, Li N, Borad N, Sarkisian A, et al. Cooling relief of acute and chronic itch requires TRPM8 channels and neurons. J Invest Dermatol. 2018;138:1391–1399. doi: 10.1016/j.jid.2017.12.025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Kang SY, Choi MG, Wei ET, Selescu T, Lee SY, Kim JC, et al. TRPM8 agonist (cryosim-1) gel for scalp itch: a randomised, vehicle-controlled clinical trial. J Eur Acad Dermatol Venereol. 2022;36:e588–e589. doi: 10.1111/jdv.18080. [DOI] [PubMed] [Google Scholar]
- 27.Thorburn PT, Riha RL. Skin disorders and sleep in adults: where is the evidence? Sleep Med Rev. 2010;14:351–358. doi: 10.1016/j.smrv.2009.12.001. [DOI] [PubMed] [Google Scholar]
- 28.Gupta MA, Simpson FC, Gupta AK. Psoriasis and sleep disorders: a systematic review. Sleep Med Rev. 2016;29:63–75. doi: 10.1016/j.smrv.2015.09.003. [DOI] [PubMed] [Google Scholar]
- 29.Lavery MJ, Stull C, Kinney MO, Yosipovitch G. Nocturnal pruritus: the battle for a peaceful night’s sleep. Int J Mol Sci. 2016;17:425. doi: 10.3390/ijms17030425. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Yosipovitch G, Xiong GL, Haus E, Sackett-Lundeen L, Ashkenazi I, Maibach HI. Time-dependent variations of the skin barrier function in humans: transepidermal water loss, stratum corneum hydration, skin surface pH, and skin temperature. J Invest Dermatol. 1998;110:20–23. doi: 10.1046/j.1523-1747.1998.00069.x. [DOI] [PubMed] [Google Scholar]
- 31.Sanders KM, Akiyama T. The vicious cycle of itch and anxiety. Neurosci Biobehav Rev. 2018;87:17–26. doi: 10.1016/j.neubiorev.2018.01.009. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Survey Instrument
Summary of unidimensional itch intensity scale scores in the total 206 patients with chronic pruritus
Summary of scratching behaviors by pruritus descriptors
Summary of the ItchyQoL findings by scratching behaviors
Summary of pruritus descriptors by the clinical characteristics of the patients
Summary of unidimensional itch intensity scales in patients with dermatologic diseases
Summary of pruritus and scratching descriptors in patients with chronic pruritus
Characteristics of scratching behaviors in patients with dermatologic diseases