Sleep Disturbances in Patients with Psoriasis

Psoriasis is a common, immune-mediated inflammatory skin disorder characterized by well-demarcated erythematous plaques and papules with micaceous scale. Psoriasis affects approximately 2% of the US population and has a bimodal age of onset which has been discovered through many large scale studies.¹ The mean age of onset for the first presentation of psoriasis can range from 15 to 20 years of age, with a second peak occurring at 55–60 years.² Traditionally considered a disease that mainly affects the skin, research in the past decade has begun to highlight many co-morbidities that are associated with psoriasis.

Recently, this issue has gained more recognition with publication of The American Academy of Dermatology (AAD) and National Psoriasis Foundation (NPF) guidelines for the management and treatment of psoriasis with special attention given to comorbidities which include psoriatic arthritis, inflammatory bowel disease, cardiovascular disease, metabolic syndrome and depression.³ Given that sleep disorders are considered an independent risk factor for some of these well recognized psoriasis co-morbidities, there is a renewed interest in studying sleep disturbance in patients with psoriasis.

The association between sleep disturbances and psoriasis is multidirectional and more research is needed to discover the factors associated with this condition.⁴ “A growing body of literature has shown us that patients with psoriasis are more likely to report sleep disturbance when compared to the general population. This is important because chronic sleep impairment is an independent risk factor for cardiovascular disease, metabolic disorders, and mental health disorders like depression – the same comorbidities that lead to increased morbidity and mortality in psoriasis patients. Therefore, it is possible that sleep disturbance could be further increasing patients’ risk for developing these conditions”, said Tina Bhutani, MD, MAS a Board-Certified Dermatologist who is an Associate Professor of Dermatology and Co-Director of the Psoriasis and Skin Treatment Center at The University of California, San Francisco in San Francisco, CA.

A study conducted by Sahin et. al. in the Journal of the European Academy of Dermatology and Venerology sought to answer how psoriasis affects sleep by identifying clinical, demographic and psychological factors associated with sleep disturbances in psoriasis.⁵ The authors utilized a cross-sectional, questionnaire based study which included clinical interviews along with assessments of disease severity. 334 patients were recruited and interviewed along with 126 control subjects. Participants filled out validated questionnaires about psoriasis and sleep disturbances including The Global Pittsburgh Sleep Quality Index (PSQI), Short Form 36 Physical Component Summary (HR-QoL) and mental component summary (MCS), The Hospital Anxiety and Depression Scale (HADS-A) and the Dermatology Life Quality Index (DLQI). Psoriasis severity was assessed using the Psoriasis Area and Severity Index (PASI), body surface area (BSA) and co-morbidity severity was assessed with the Cumulative Illness Rating Scale (CIRS). Pruritus was assessed with the Visual Analogue Scale (VAS).

The authors found many interesting results. Poor sleep was more frequent in psoriasis patients as compared to control subjects and 79% of psoriasis patients reported having pruritus. Patients with pruritus had more diminished components of subjective sleep quality, sleep latency, sleep disturbances and daytime dysfunction than patients without pruritus. Psoriasis patients with poor sleep reported more intense pruritus. Pruritus intensity, both average and maximum, correlated negligibly with global sleep quality impairment. Patients and control subjects with poor sleep had more severe comorbidities. Patients with sleep disturbance had a more depressed mood, were more anxious and had more impaired quality of life. In psoriasis patients, greater levels of anxiety and depression forecasted sleep impairment better than pruritus parameters overall, such as nighttime exacerbations. Psoriasis patients reported shorter sleep duration versus control subjects.

This study highlighted a large prevalence of sleep disturbance in psoriasis patients and revealed clinical and demographic variables associated with poor sleep. Through the use of clinical interviews, physical examinations and validated questionnaires, the authors found a disconcertingly high prevalence of sleep disturbance in psoriasis patients. Limitations of this study includes the inability to make conclusions about casual relationships between sleep disturbance and identified factors, due to the cross sectional design. As per the authors, this study is one of the most comprehensive investigations on this topic

Pruritus intensity in nearly half of the patients varied throughout the day, worsening most frequently in the evening which likely directly interfered with sleep. Given this finding, the authors concluded that pruritus around bedtime is an important predictor of sleep impairment, independent of the intensity of the pruritus. This finding is clinically relevant as it demonstrates that treating pruritus exacerbations at bedtime is an important therapeutic objective. Short term options for treating the nighttime pruritis associated with psoriasis include sedating antihistamines such as hydroxyzine.⁶ However, treating the underlying disorder (in this case, psoriasis) should always be the goal.

Sleep has even been implicated in immune function, and given the immune-mediate nature of psoriasis, dermatologists should be encouraged to emphasize sleep hygiene as part of their treatment regimen for inflammatory skin disease patients.⁷ “I completely agree with the authors that sleep impairment is something that we should be asking our patients about and future studies looking at the impact of screening for sleep disturbance and promoting better quality sleep are needed” said Dr. Bhutani. She also commented on this topic, “sleep improvement could be a relatively simple behavior modification that could lead to meaningful improvement in patient health, longevity, and overall quality of life.” Given that psoriasis patients with disrupted sleep exhibited higher levels of anxiety and depression, referral to a mental health specialist may also be beneficial.

In conclusion, this study highlighted the fact that sleep disturbances in patients with psoriasis is highly prevalent. During clinic visits, dermatology providers should consider screening for sleep disturbances as part of the regular follow up visit for inflammatory skin disease. Specifically, patients should be asked about intensity of pruritis before bedtime and if they have any feelings of anxiety or depression as related to their sleep dysfunction. Treatment of co-morbid conditions should be prioritized in psoriasis patients with sleep disturbances, as this disorder is considered an independent risk factor for common psoriasis co-morbidities. It will be exciting to see more studies on this interesting topic in the future.

References

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2. Smith AE, Kassab JY, Rowland Payne CM, Beer WE. Bimodality in age of onset of psoriasis, in both patients and their relatives. Dermatology. 1993;186(3):181-186. doi:10.1159/000247341

3. Elmets CA, Leonardi CL, Davis DMR, et al. Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with awareness and attention to comorbidities. Journal of the American Academy of Dermatology. 2019;80(4):1073-1113. doi:10.1016/j.jaad.2018.11.058

4. Halioua B, Chelli C, Misery L, Taieb J, Taieb C. Sleep Disorders and Psoriasis: An Update. Acta Derm Venereol. 2022;102:adv00699. doi:10.2340/actadv.v102.1991

5. Sahin E, Hawro M, Weller K, et al. Prevalence and factors associated with sleep disturbance in adult patients with psoriasis. J Eur Acad Dermatol Venereol. 2022;36(5):688-697. doi:10.1111/jdv.17917

6. Patel T, Ishiuji Y, Yosipovitch G. Nocturnal itch: why do we itch at night? Acta Derm Venereol. 2007;87(4):295-298. doi:10.2340/00015555-0280

7. Myers B, Reddy V, Chan S, Thibodeaux Q, Brownstone N, Bhutani T. Sleep, Immunological Memory, and Inflammatory Skin Disease. DRM. 2021;237(6):1035-1038. doi:10.1159/000510082