The bidirectional interactions between psoriasis and obstructive sleep apnea.

Psoriasis is a chronic inflammatory skin disorder which can impair general routine activities and has been closely related to poor quality of life. Pruritus and scratching are frequently observed, occurring mainly during sleep and precipitating nighttime arousals. Indeed, sleep quality has been shown to be negatively affected in psoriatic patients, in a close relationship with stress exposure and immune response. Although psoriasis is known to impair sleep, leading to insomnia, its association with obstructive sleep apnea (OSA) is controversial. Similarly, OSA is considered a multifactorial inflammatory disease, characterized by intermittent hypoxia, sleep fragmentation and autonomic dysfunction, with important outcomes on the cardiovascular and metabolic systems. Importantly, immunological activities and pro-inflammatory cytokines play a prominent role in both OSA and psoriasis. Currently it is not clear whether OSA is a risk factor for psoriasis development or if psoriasis is a possible predictor of OSA. Thus, our main purpose is to provide an overview of this intriguing relationship and show the current link between psoriasis and OSA in a bidirectional relationship.