Poor Sleep: An Underestimated Symptom of Psoriasis

Psoriasis is a disease affecting 1-3% of the population that can be physically, socially, and psychologically disabling.^[1] Disrupted sleep is one component that can greatly affect the quality of life in people with psoriasis.^[1] Approximately 60% of people with psoriasis experience poor sleep quality.^[1]

Psoriasis Causes Poor Sleep

While sleep is impaired in those with psoriasis, the causes for the poor sleep are not well known. Some causes have been characterized to other symptoms that arise with psoriasis. Pruritus, or itchy skin, occurs in 70% to 90% of people with psoriasis.^[2] While itchy skin decreases quality of life, it also disturbs sleep and worsens quality of life.^[3]

Depression

Another cause of sleep impairment in psoriasis stems from its strong association with depression.^[2] While psoriasis has an association with psychiatric morbidity in general, between 10 and 58% of patients with psoriasis also have depression.^[2] Depression is the most common psychiatric disorder associated with insomnia.^[4] The prevalence of depression is also higher among those with psoriasis as compared with other dermatologic diseases, which may be due to the psychological distress relating to both physical and social factors that accompany psoriasis.^[2]

Sleep Apnea

People with psoriasis are frequently overweight or obese which may result in obstructive sleep apnea that is often undiagnosed in people with insomnia.^[5] Poor sleep is common in psoriasis and associated with psychological and physical factors.^[6] Psoriasis is present in significantly greater numbers in those with obstructive sleep apnea (OSA) as compared to those without OSA.^[7,8] There is 36% - 81.8% prevalence of OSA in those with psoriasis as compared to 2% - 4% OSA prevalence in the general population.^[9] Psoriasis was found to be associated with risk of OSA but not with its severity regardless of age or gender.^[7]

Sleep Worsens Psoriasis

Sleep and psoriasis seem to influence each other. Not only does psoriasis worsen sleep, but poor sleep seems to worsen psoriasis too.^[10]

One study focused on how sleep affects the immune system in psoriasis.^[10] Adult male mice with psoriasis undergoing 48 hours of sleep deprivation had increased blood levels of inflammatory signals, such as interleukins IL-1β, IL-6, and IL-12.^[10] At the same time, the mice also made less of the anti-inflammatory signal IL-10.^[10] In other words, there was an unregulated activation of the inflammatory process when psoriasis was combined with poor sleep. Once the sleep cycle was allowed to normalize, the inflammatory signals improved. In human studies, sleep has been found to be a mediating factor between severity of pruritus (itchiness) and quality of life in people with psoriasis.^[5] These studies point to the important role of sleep on the inflammatory system and therefore psoriatic development.

A Vicious Cycle of Psoriasis and Poor Sleep

Psoriasis plays a role in sleep disturbances while at the same time, sleep disturbances and lack of sleep play a role in exacerbation of psoriasis.

Understanding the problems with sleep in psoriasis may help improve quality of living and disease treatment.^[1] Given that poor sleep is both common in psoriasis and associated with psychological health factors, patients should be empowered to discuss sleep patterns with their health care providers and, in turn, health care providers should ask about sleep patterns in those with psoriasis.^[6]