The Sleep Disorders Linked to Psoriasis
Psoriasis is linked to a number of health issues such as high blood pressure, diabetes, obesity, and psychiatric disorders. Since all of these health issues also affect the course of sleep disorders, Canadian researchers conducted a systematic review to determine the relationship between psoriasis, psoriatic arthritis, and sleep disorders. Their findings were published in the journal Sleep Medicine Reviews.
Analyzing the studies
Researchers analyzed studies that investigated the prevalence and characteristics of sleep disorders among participants who had a clinical diagnosis of psoriasis or psoriatic arthritis. A total of 33 studies were analyzed and researchers identified the following sleep disorders among participants.
Psoriasis and insomnia risk
Those with self-diagnosed psoriasis were found to have greater odds for developing insomnia (the odds ratio was 1.44). In other words The odds of insomnia was 1.44 times higher among those with psoriasis compared to those without insomnia. Those with physician-diagnosed chronic plaque psoriasis were found to have even greater odds (odds ratio of 4.3). The review suggested that the medications etanercept and adalimumab may improve the sleep of insomniacs with psoriasis.
Psoriasis and obstructive sleep apnea risk
The review identified five studies that found obstructive sleep apnea (OSA) was present in between 36 and 82 percent of psoriasis patients. Individuals with psoriasis were found to be 3.8 times more likely to develop OSA (odds ratio of 3.86). Interestingly, the review also found that those with OSA had greater odds for developing psoriasis (ratio of 2.3).
Restless legs syndrome and periodic limb movement disorder
Approximately 15 percent of individuals with psoriasis were found to have restless legs syndrome — and this is higher than the prevalence rate of the general population, which is thought to be between five and 10 percent. The review identified one study which investigated periodic limb movement disorder (PLMD) among individuals with psoriasis. It found those with psoriasis had significantly higher periodic limb movement index scores compared to controls. In other words, individuals with psoriasis moved their legs far more frequently during sleep compared to those without psoriasis.
Psoriasis, narcolepsy, and shift work disorder
The review identified one study which found 1.3 percent of those with narcolepsy had psoriasis and 1.9 percent of those with narcolepsy had atopic dermatitis. A separate study found nightshift workers were 1.23 times more likely to develop psoriasis within 10 years compared to dayshift workers.
Does psoriasis treatment decrease sleep disturbance?
The authors of the review confirmed that both etanercept and adalimumab improved skin lesions in psoriasis and, among those with insomnia, both drugs also improved sleep disturbance, quality of life, fatigue, and symptoms of depression. When it came to OSA, the authors of the review concluded that adalimumab was not found to have a direct effect on OSA severity.
The sleep disorders linked to psoriasis
After analyzing the reviewed studies, the authors concluded that psoriasis and psoriatic arthritis were linked with OSA and restless legs syndrome. The authors determined that there was no conclusive evidence to suggest psoriasis or psoriatic arthritis was associated with a higher prevalence of insomnia, periodic limb movement disorder, narcolepsy, or shift work disorder.
Why is psoriasis linked to disturbed sleep?
As pointed out by the review, extensive research suggests the relationship between psoriasis and insomnia is down to the itchiness and pain associated with the condition. Insomnia was present in between six and 45 percent of psoriasis patients. This large variation may be explained by patient expectations, comorbid depression and anxiety, and poor sleep hygiene — all of which can influence the transition from discomfort to chronic insomnia.
The role of the circadian rhythm and temperature
The authors of the review suggested that the alterations in skin blood flow and skin dryness associated with psoriasis can disrupt the drop in core body temperature that is necessary for sleep onset — and this can alter the circadian rhythm. The review suggested that maintaining a cool ambient room temperature may be helpful for those with extensive psoriasis who struggle to fall asleep.
The importance of diagnosing sleep disorders
The review concluded with urging dermatologists and other practitioners who treat individuals with psoriasis and psoriatic arthritis to consider the possible presence of an underlying sleep disorder. The authors suggested that those with multiple diseases associated with their psoriasis should undergo a sleep study to determine whether they also have obstructive sleep apnea - particularly if they are significantly clinically depressed, obese, hypertensive, or diabetic.