Abstract
Background
Prurigo nodularis (PN) is a chronic inflammatory skin condition characterized by severely itchy and often painful bumps on the arms, legs, and trunk. It is unknown whether patients with PN have increased risk of developing sleep disorders.
Objective
To evaluate the association of PN with sleep disorders.
Methods
This retrospective, population-level, matched-cohort study was conducted using The Health Improvement Network. The study included 4193 patients with newly diagnosed PN and 4193 age, sex, and race/ethnicity-matched controls. A Cox regression model was used to assess the development of sleep disorders, including insomnia, sleep apnea, and restless legs syndrome, in patients with PN compared with control patients.
Results
Compared with controls, PN was associated with insomnia (adjusted hazard ratio [aHR] = 1.77; 95% CI = 1.48-2.12) and overall sleep disorder (aHR = 1.72; 95% CI = 1.46-2.02), but not with sleep apnea (aHR = 1.51; 95% CI = 0.93-2.44) or restless legs syndrome (aHR = 1.54; 95% CI = 0.92-2.57).
Limitations
As a retrospective cohort study, our analysis is subject to potential confounders not already included.
Conclusions
PN was associated with subsequent development of insomnia. Thus, clinicians should consider insomnia among patients with PN and develop strategies for treatment and prevention.
Key words: insomnia, itch, prurigo nodularis, pruritus, restless legs syndrome, sleep, sleep apnea
Capsule Summary.
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Prurigo nodularis (PN) is a chronic inflammatory dermatosis characterized by debilitating itch and associated with systemic and psychiatric comorbidities.
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Patients with PN are at elevated risk of development of insomnia. Health care providers should be aware of this increased risk of insomnia and develop appropriate strategies for screening and treatment.
Introduction
Prurigo nodularis (PN) is a chronic inflammatory dermatosis characterized by severely pruritic, symmetrically distributed nodules and papules.1 The lesions commonly involve the extensor surfaces of the limbs and trunk.2 Patients usually experience intense itch with associated pain, burning, or stinging.3 PN is associated with multiple systemic conditions, including chronic kidney disease, HIV infection, and type 2 diabetes mellitus.4, 5, 6 Patients with PN experience the highest decrease in quality of life out of all pruritic dermatoses, with greater impairment in quality of life than that due to stroke or schizophrenia.7 Patients have reported reduced social participation and severe sleep disturbances, as well as negative emotion and cognition.7 Currently, the pathophysiology of PN remains poorly understood, but recent studies suggest that pro-inflammatory cytokines—such as interleukin-13, interleukin-22, and interleukin-31—and neuropeptides in lesional skin play a key role in altered nerve density and increased inflammation in PN.8,9 Currently, Dupixent (dupilumab) injection is the only treatment for PN approved by the US Food and Drug Administration, and treatment remains challenging.10,11
Although chronic pruritus has been shown to significantly reduce sleep quality, the risk of sleep disorders in patients with PN are currently undefined.12 A potential explanation for the limited epidemiologic data available on PN and sleep disorders is that PN is relatively uncommon and was grouped with other chronic pruritus conditions in previous disease classification systems up until 2015.13 Increased understanding of the relationship between PN and sleep disorders can facilitate early identification of comorbidity and optimal clinical management. In this population-based, matched-cohort study, we sought to determine whether there is an association between diagnosed PN and sleep disorders—insomnia, sleep apnea, and restless legs syndrome.
Methods
Data source
This retrospective cohort study utilized data from The Health Improvement Network (THIN), a primary care database based in the United Kingdom using routinely collected electronic health record data from general practitioners. The THIN database contains data on patient demographics, medical diagnoses, prescriptions, and lifestyle characteristics. It has data from >3 million patients collected from >385 general practices, serving as a representative sample for the general United Kingdom population in age, sex, ethnicity, and other demographics.14 Because THIN contains only deidentified data, this study was exempt from the institutional review board. Diagnoses in THIN are coded according to diagnostic Read codes.15 THIN has been used extensively in epidemiologic research for different medical conditions.16, 17, 18, 19, 20
Study cohorts and controls
Participants were identified and followed from THIN between January 1, 1994, and July 31, 2021. Patients with PN were identified using the Read code F13z200. For each patient with PN, 1 matched subject without PN was selected based on age, sex, and race/ethnicity. Additional covariates considered in this study besides age, sex, and race/ethnicity were body mass index and pre-existing comorbidities (major depressive disorder and anxiety disorder as confounders for all sleep disorder outcomes, and iron deficiency anemia as a confounder for restless legs syndrome) diagnosed before the index date.
Outcome
The primary outcome was new-onset sleep disorders, including insomnia (Read codes 1B1B.00, 1B1B.11, 1B1B000, 1B1B100, 1B1B200, E274.12, E274100, E274111, E274200, Eu51000, R005.11, R005100, R005200, 1B1B.00, 1BX0.00, Fy00.00), sleep apnea (Read codes Fy03.00, Fy03.11, H5B..00, H5B0.00, R005311, R005312, R005100, R005300), and restless legs syndrome (Read code F13z20). The index date for the PN group was defined as the first date on which PN was diagnosed. The index date for the controls was the PN diagnosis date of the matched patient with PN. We excluded patients with previous diagnosis of any sleep disorder (insomnia, sleep apnea, restless legs syndrome, narcolepsy) before the index date. We also excluded patients who were followed <1 year before or after the index date. Multiple imputation was performed to replace missing data. The study design is depicted in Supplementary Figure 1 (available via Mendeley at https://data.mendeley.com/datasets/4tbr65zn27/1).
Statistical analysis
First, we compared characteristics between individuals with and without PN using 2-tailed t-test for continuous variables and Pearson’s χ2 test for categorical variables. Second, we calculated incidence rates (per 1000 person-years) for each sleep disorder. We created Kaplan Meier curves showing proportion of patients without sleep disorder over time and compared PN against control groups with log-rank test. We determined absolute risk and relative risk (RR) with 95% CIs and P values (calculated using Z-test) for the association between PN and sleep disorders. To allow for full 1-year, 5-year, and 10-year observation periods, only patients who were followed for over 1 year, 5 years, and 10 years after their index date, respectively, were included. Finally, Cox regression models were used to assess the association between PN and sleep disorders. After adjusting for age, sex, race/ethnicity, comorbidities, and body mass index, adjusted hazard ratios (aHRs) with 95% CIs were used to establish the strength of the association. After stratification of patients by age and sex, subanalysis was performed to calculate aHRs for the association between PN and sleep disorders within each subgroup. Study values are reported as median (SD) or number (percentage). Statistical analyses were performed in Python 3.9.12 using lifelines and scipy packages. A P value of < .05 was considered statistically significant.
Results
We identified 4193 patients with PN and 4193 matched control patients. Baseline characteristics for the study cohorts are depicted in Table I. Most patients were female (57.4%), and the median age was 57.0 years with a SD of 19.4 years.
Table I.
Baseline demographic characteristics of patients with prurigo nodularis versus control patients
| Characteristics | Prurigo nodularis N = 4193 |
Controls N = 4193 |
P value |
|---|---|---|---|
| Age (y), median (SD) | 57.0 (19.4) | 57.0 (19.4) | 1.0 |
| Sex, n (%) | 1.0 | ||
| Male | 1785 (42.6) | 1785 (42.6) | |
| Female | 2408 (57.4) | 2408 (57.4) | |
| Ethnicity, n (%) | 1.0 | ||
| White | 1934 (46.1) | 1934 (46.1) | |
| Black | 80 (1.9) | 80 (1.9) | |
| Asian | 191 (4.6) | 191 (4.6) | |
| Other/unknown | 1988 (47.4) | 1988 (47.4) | |
| Comorbidities, n (%) | |||
| Major depressive disorder | 133 (3.2) | 59 (1.4) | <.001 |
| Anxiety disorder | 331 (7.9) | 226 (5.4) | <.001 |
| Iron deficiency anemia | 195 (4.7) | 131 (3.1) | <.001 |
| BMI (kg/m2) median (SD) | 28.4 (4.7) | 26.9 (4.3) | <.001 |
Bold values denote statistical significance at the P < .05 level.
BMI, Body mass index.
Of the 4193 patients with PN, 311 (7.4%) were diagnosed with insomnia, 44 (1.0%) with sleep apnea, 37 (0.88%) with restless legs syndrome, and 374 (8.9%) with overall sleep disorder after the index date. In contrast, out of the 4193 control patients, 199 (4.7%) were diagnosed with insomnia, 28 (0.67%) with sleep apnea, 25 (0.60%) with restless legs syndrome, and 243 (5.8%) with overall sleep disorder after the index date. The incidence rate of insomnia was 10.2 per 1000 person-years in patients with PN, compared with 5.6 per 1000 person-years in controls. Sleep apnea had an incidence rate of 1.4 per 1000 person-years in patients with PN and 0.76 per 1000 person-years in controls. The incidence rate of restless legs syndrome was 1.2 per 1000 person-years and 0.68 per 1000 person-years in controls. For overall sleep disorder, the incidence rate was 12.5 per 1000 person-years in patients with PN and 6.9 per 1000 person-years in controls. Kaplan Meier curves show higher rates of all sleep disorders in patients with PN (log-rank test, P < .05 for all outcomes) compared with control patients (Supplementary Fig 2, available via Mendeley at https://data.mendeley.com/datasets/4tbr65zn27/1).
Table II displays absolute risks and RRs along with 95% CIs and P values. At 1 year, patients with PN experienced significantly increased risk of overall sleep disorders (RR = 1.72; 95% CI = 1.16-2.54) and insomnia (RR = 1.75; 95% CI = 1.14-2.70), and insignificant increased risk of sleep apnea (RR = 2.5; 95% CI = 0.49-12.88) and restless legs syndrome (RR = 1.2; 95% CI = 0.37-3.93). At 5 years, patients with PN experienced significantly increased risk of overall sleep disorders (RR = 1.65; 95% CI = 1.30-2.08) and insomnia (RR = 1.57; 95% CI = 1.21-2.04), and insignificant increased risk of sleep apnea (RR = 1.87; 95% CI = 0.94-3.73) and restless legs syndrome (RR = 2.00; 95% CI = 0.95-4.20). At 10 years, patients with PN experienced significantly increased risk of overall sleep disorders (RR = 1.76; 95% CI = 1.37-2.26), insomnia (RR = 1.67; 95% CI = 1.27-2.20), and sleep apnea (RR = 3.11; 95% CI = 1.37-7.03), and insignificant increased risk of restless legs syndrome (RR = 1.47; 95% CI = 0.66-3.27).
Table II.
Absolute and relative risks of insomnia, sleep apnea, restless legs syndrome, and overall sleep disorders after 1 year, 5 years, and 10 years
| Sleep disorder | Absolute risk, No. (%) |
Relative risk (95% CI) | P value | |
|---|---|---|---|---|
| Prurigo nodularis | Controls | |||
| Insomnia, y | ||||
| 1 | 56 (1.34) | 32 (0.76) | 1.75 (1.14-2.70) | .01 |
| 5 | 129 (5.07) | 95 (3.22) | 1.57 (1.21-2.04) | <.005 |
| 10 | 110 (9.21) | 82 (5.52) | 1.67 (1.27-2.20) | <.005 |
| Sleep apnea, y | ||||
| 1 | 5 (0.12) | 2 (0.05) | 2.5 (0.49-12.88) | .27 |
| 5 | 21 (0.83) | 13 (0.44) | 1.87 (0.94-3.73) | .07 |
| 10 | 20 (1.68) | 8 (0.54) | 3.11 (1.37-7.03) | .006 |
| Restless legs syndrome, y | ||||
| 1 | 6 (0.14) | 5 (0.12) | 1.2 (0.37-3.93) | .76 |
| 5 | 19 (0.74) | 11 (0.37) | 2.00 (0.95-4.20) | .07 |
| 10 | 13 (1.08) | 11 (0.74) | 1.47 (0.66-3.27) | .34 |
| Any sleep disorder, y | ||||
| 1 | 67 (1.60) | 39 (0.93) | 1.72 (1.16-2.54) | .007 |
| 5 | 162 (6.37) | 114 (3.87) | 1.65 (1.30-2.08) | <.005 |
| 10 | 136 (11.4) | 96 (6.46) | 1.76 (1.37-2.26) | <.005 |
Bold values denote statistical significance at the P < .05 level.
Tables III and IV depict the results for the Cox regression models. PN was associated with insomnia (aHR = 1.77; 95% CI = 1.48-2.12) and overall sleep disorder (aHR = 1.72; 95% CI = 1.46-2.02), but not with sleep apnea (aHR = 1.51; 95% CI = 0.93-2.44) or restless legs syndrome (aHR = 1.54; 95% CI = 0.92-2.57). Other variables associated with insomnia were major depressive disorder (aHR = 2.01; 95% CI = 1.33-3.06) and anxiety disorder (aHR = 1.62; 95% CI = 1.21-2.17). Obesity, defined as body mass index >30, was associated with sleep apnea (aHR 10.04; 95% CI = 4.28-23.5), whereas female sex was negatively associated with sleep apnea (aHR 0.39; 95% CI = 0.24-0.64). Major depressive disorder (aHR 5.67; 95% CI = 2.53-12.7) and age group between 60 to 69 years (aHR 2.35; 95% CI = 1.23-4.50) was associated with restless legs syndrome.
Table III.
Cox regression analyses of variables associated with risk of overall sleep disorder in patients with prurigo nodularis and control patients
| Outcome |
Overall sleep disorder |
||
|---|---|---|---|
| Variables | Adjusted hazard ratio | 95% CI | P value |
| Prurigo nodularis | 1.72 | 1.46-2.02 | <.005 |
| Age, y | |||
| <30 | 0.80 | 0.58-1.10 | .17 |
| 30-39 | 0.88 | 0.64-1.20 | .42 |
| 40-49 | 1.01 | 0.79-1.30 | .93 |
| 50-59 | Reference | --- | --- |
| 60-69 | 1.04 | 0.82-1.32 | .76 |
| 70-79 | 0.94 | 0.72-1.24 | .68 |
| ≥80 | 0.93 | 0.65-1.32 | .69 |
| Sex | |||
| Male | Reference | --- | --- |
| Female | 1.00 | 0.85-1.18 | 1.00 |
| Race | |||
| White | Reference | --- | --- |
| Black | 1.08 | 0.59-1.98 | .80 |
| Asian | 1.04 | 0.71-1.54 | .83 |
| Other | 0.94 | 0.80-1.10 | .44 |
| Major depressive disorder | 2.17 | 1.50-3.13 | <.005 |
| Anxiety disorder | 1.47 | 1.12-1.94 | .01 |
| BMI, kg/m2 | |||
| <25.0 | Reference | --- | --- |
| 25.0-29.9 | 0.73 | 0.59-0.89 | <.005 |
| ≥30 | 1.24 | 0.98-1.56 | .07 |
Bold values denote statistical significance at the P < .05 level.
BMI, Body mass index.
Table IV.
Cox regression analyses of variables associated with individual sleep disorders (insomnia, sleep apnea, and restless legs syndrome) in patients with prurigo nodularis and control patients
| Outcome |
Insomnia |
Sleep apnea |
Restless legs syndrome |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Variables | aHR | 95% CI | P value | aHR | 95% CI | P value | aHR | 95% CI | P value |
| Prurigo nodularis | 1.77 | 1.48-2.12 | <.005 | 1.51 | 0.93-2.44 | .10 | 1.54 | 0.92-2.57 | .10 |
| Age, y | |||||||||
| <30 | 0.86 | 0.61-1.21 | .40 | 0.94 | 0.31-2.83 | .92 | 0.40 | 0.11-1.41 | .15 |
| 30-39 | 0.87 | 0.61-1.23 | .43 | 1.59 | 0.79-3.20 | .19 | 0.17 | 0.02-1.28 | .09 |
| 40-49 | 1.11 | 0.84-1.46 | .45 | 1.04 | 0.55-1.98 | .91 | 0.34 | 0.11-1.03 | .06 |
| 50-59 | Reference | --- | --- | Reference | --- | --- | Reference | --- | --- |
| 60-69 | 1.03 | 0.78-1.35 | .85 | 0.48 | 0.24-0.99 | .05 | 2.35 | 1.23-4.50 | .01 |
| 70-79 | 1.06 | 0.79-1.43 | .68 | 0.23 | 0.07-0.75 | .02 | 1.19 | 0.52-2.69 | .68 |
| ≥ 80 | 1.07 | 0.74-1.56 | .71 | 0.43 | 0.10-1.85 | .26 | 0.69 | 0.20-2.45 | .57 |
| Sex | |||||||||
| Male | Reference | --- | --- | Reference | --- | --- | Reference | --- | --- |
| Female | 1.07 | 0.90-1.29 | .43 | 0.39 | 0.24-0.64 | <.005 | 1.68 | 0.97-2.90 | .06 |
| Race | |||||||||
| White | Reference | --- | --- | Reference | --- | --- | Reference | --- | --- |
| Black | 1.35 | 0.73-2.47 | .34 | --- | --- | --- | --- | --- | --- |
| Asian | 1.12 | 0.74-1.70 | .59 | 0.86 | 0.26-2.85 | .80 | 0.54 | 0.07-3.90 | .54 |
| Other | 0.91 | 0.76-1.09 | .30 | 1.07 | 0.67-1.72 | .77 | 1.12 | 0.68-1.86 | .66 |
| Major depressive disorder | 2.01 | 1.33-3.06 | <.005 | 1.39 | 0.43-4.49 | .59 | 5.67 | 2.53-12.7 | <.005 |
| Anxiety disorder | 1.62 | 1.21-2.17 | <.005 | 0.78 | 0.28-2.17 | .64 | 0.80 | 0.29-2.23 | .67 |
| Iron deficiency anemia | --- | --- | --- | --- | --- | --- | 1.25 | 0.39-4.05 | .71 |
| BMI, kg/m2 | |||||||||
| <25.0 | Reference | --- | --- | Reference | --- | --- | Reference | --- | --- |
| 25.0-29.9 | 0.72 | 0.58-0.90 | <.005 | 0.42 | 0.15-1.16 | .09 | 1.09 | 0.55-2.16 | .80 |
| ≥30 | 0.86 | 0.66-1.13 | .28 | 10.04 | 4.28-23.5 | <.005 | 1.33 | 0.61-2.90 | .47 |
Bold values denote statistical significance at the P < .05 level.
aHR, Adjusted hazard ratio; BMI, body mass index.
Subanalysis after stratification by age groups and sex showed significant association between PN and insomnia and overall sleep disorder in both sexes, and every age group except groups of <30 years and 70-79 years (Table V). No association was found between PN and sleep apnea or restless legs syndrome in either sex or any age group.
Table V.
Adjusted hazard ratios of sleep disorders in patients with prurigo nodularis vs controls, stratified by age and sex
| Subgroup |
Prurigo nodularis vs controls |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Outcome | Insomnia |
Sleep apnea |
Restless legs syndrome |
Overall sleep disorder |
||||||||
| aHR | 95% CI | P value | aHR | 95% CI | P value | aHR | 95% CI | P value | aHR | 95% CI | P value | |
| Total | 1.77 | 1.48-2.12 | <.005 | 1.51 | 0.93-2.44 | .10 | 1.54 | 0.92-2.57 | .10 | 1.72 | 1.46-2.02 | <.005 |
| Age, y | ||||||||||||
| <30 | 1.56 | 0.88-2.76 | .13 | 2.34 | 0.31-17.7 | .41 | 1.53 | 0.18-12.6 | .70 | 1.59 | 0.93-2.74 | .09 |
| 30-39 | 2.09 | 1.12-3.91 | .02 | 2.94 | 0.76-11.3 | .12 | 3.48 | 0.14-85.5 | .45 | 2.26 | 1.28-3.98 | <.005 |
| 40-49 | 2.09 | 1.36-3.20 | <.005 | 1.62 | 0.57-4.56 | .36 | 2.70 | 0.44-16.5 | .28 | 2.05 | 1.38-3.05 | <.005 |
| 50-59 | 1.55 | 1.05-2.28 | .03 | 1.36 | 0.58-3.19 | .48 | 2.26 | 0.77-6.60 | .14 | 1.66 | 1.18-2.34 | <.005 |
| 60-69 | 2.08 | 1.36-3.17 | <.005 | 1.05 | 0.31-3.56 | .94 | 0.98 | 0.47-2.07 | .97 | 1.76 | 1.23-2.53 | <.005 |
| 70-79 | 1.20 | 0.76-1.89 | .43 | 0.39 | 0.04-4.42 | .45 | 1.88 | 0.56-6.31 | .31 | 1.17 | 0.77-1.80 | .46 |
| ≥80 | 2.67 | 1.34-5.41 | .01 | 1.05 | 0.07-16.1 | .97 | 0.65 | 0.08-5.09 | .68 | 2.39 | 1.25-4.57 | .01 |
| Sex | ||||||||||||
| Male | 1.74 | 1.30-2.32 | <.005 | 1.43 | 0.76-2.68 | .27 | 1.36 | 0.55-3.37 | .51 | 1.66 | 1.28-2.14 | <.005 |
| Female | 1.79 | 1.42-2.26 | <.005 | 1.37 | 0.64-2.92 | .42 | 1.69 | 0.90-3.16 | .10 | 1.76 | 1.42-2.17 | <.005 |
Bold values denote statistical significance at the P < .05 level.
aHR, Adjusted hazard ratio.
Discussion
In this study using a large, population-based cohort, we demonstrated significantly increased risk of developing insomnia among patients with PN compared with control patients. Stratified analysis showed that the risk of insomnia was significantly increased across both sexes and all age groups except those aged under 30 years and between 70 and 79 years. Our study also revealed lack of association between PN and sleep apnea and restless legs syndrome.
Limited research has been conducted on the relationship between PN and sleep. Gwillim et al21 investigated 39 patients with PN using validated questionnaires, finding that the majority (61.5%) of patients with PN experienced sleep disturbance due to pruritus to a great extent and that sleep disturbance significantly correlated to pruritus timing at night.21 Konda et al22 assessed the sleep quality of 39 patients with PN using the Pittsburgh Sleep Quality Index, a self-rated questionnaire for measuring sleep quality and disturbances over a 1-month time interval, finding that over half of patients with PN (53.8%) had poor sleep quality.22,23 Other studies have assessed the effect of PN treatments on sleep quality in patients with PN. A study by Spring et al24 examined 13 cases of patients with PN managed with methotrexate, demonstrating that methotrexate treatment resulted in significant improvement in sleep quality, as measured by a standardized patient-reported Numeric Rating Scale.24 Another study by Chiricozzi et al25 followed 27 patients with PN treated with dupilumab, finding that dupilumab improved sleep quality measured by Numeric Rating Scale scores. Finally, a randomized controlled trial of 70 patients with PN treated with nemolizumab for 12 weeks also showed improved sleep quality measured by Numeric Rating Scale scores.26
Depression and anxiety, both conditions associated with PN, are known contributors to the development of insomnia and other sleep disorders.27,28 Konda et al22 suggested that sleep disturbance in PN could be caused by associated depression, as they found sleep quality to be associated with depression severity but not pruritus severity. However, even after controlling for psychiatric comorbidities in our Cox regression models, PN was still associated with increased risk of insomnia.
The vicious itch-scratch cycle in PN, related to neuroimmune dysregulation, directly leads to sleep disturbance.10 Disrupting this cycle through rapid and sustained itch relief is crucial to restore sleep quality in patients with PN. Sleep deprivation from insomnia negatively impacts both physical and mental health and is associated with cardiometabolic and neurocognitive morbidity and mortality.29 Thus, early identification and treatment of insomnia in patients with PN is essential for improvement of long-term outcomes.
This study has some limitations. The incidence of sleep disorders and psychiatric disorders might be underestimated because only individuals who sought consultation and received medical diagnoses were included in the analysis. Furthermore, our study, being an observational matched-cohort study, is subject to potential confounders that we have not included already in the study. The THIN data set lacked information on severity of pruritus in patients with PN, so we were unable to analyze the relationship between pruritus severity and sleep disorders. Another limitation of the study is that although subgroup analysis was performed for age group and sex, it was not done for race or socioeconomic status. Additionally, the study does not include information on treatment of PN or insomnia and therefore does not analyze how treatment of PN would impact insomnia or vice versa. Finally, all patients included in our analysis were from the United Kingdom. Thus, our study findings may not be generalizable to all populations, and further research including patients with other demographics is necessary to understand cross-cultural factors regarding sleep disorders in PN.
Conclusion
In this population-based, retrospective matched-cohort study using THIN database, we found that PN was associated with subsequent development of insomnia, and not with sleep apnea or restless legs syndrome. Additional studies are needed to investigate interventions to optimize treatment of insomnia in patients with PN. Dermatologists should be aware of this elevated risk of insomnia in patients with PN for appropriate monitoring and referral for treatment.
Conflicts of interest
Dr Kwatra is an advisory board member/consultant for AbbVie, Aslan Pharmaceuticals, Arcutis Biotherapeutics, Celldex Therapeutics, Castle Biosciences, Galderma, Genzada Pharmaceuticals, Incyte Corporation, Johnson & Johnson, Leo Pharma, Novartis Pharmaceuticals Corporation, Pfizer, Regeneron Pharmaceuticals, and Sanofi and has served as an investigator for Galderma, Incyte, Pfizer, and Sanofi. Authors Joel, Taylor, Cornman, Kambala, and Reddy and Dr Gabriel have no conflicts of interest to declare.
Footnotes
Funding sources: Supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number K23AR077073-01A1, the Dermatology Foundation, and the Skin of Color Society (to Dr Kwatra).
IRB approval status: Not applicable.
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