Obstructive sleep apnea and dermatologic disorders.

Obstructive sleep apnea (OSA) is present in at least 2% of women and 4% of men, and its prevalence is increasing, because a major predisposing factor for OSA is a high body mass index. Psoriasis has the most strongly substantiated link with OSA, where the relationship may be bidirectional. Dermatologic disorders may be comorbid with OSA due to several factors: (i) the heightened proinflammatory state in OSA, which can occur independent of body mass index, and may exacerbate inflammatory dermatoses; (ii) intermittent hypoxemia may promote neovascularization and tumor growth in certain cancers, such as melanoma; (iii) obesity, present in majority of OSA patients, can be associated with a heightened proinflammatory state; (iv) upper airway obstruction due to local tumors or soft tissue swelling due to physical urticaria or angioedema; (v) acute nasal congestion in the atopic patient with allergic rhinitis; (vi) dermatologic disorders associated with other OSA risk factors (eg, acanthosis nigricans and metabolic syndrome); and (vii) a high sympathetic tone (eg, in atopic dermatitis) and resultant sleep fragmentation contributing to upper airway instability during sleep. In many instances, the dermatology patient with OSA may have other medical and psychiatric comorbidities that are also associated with increased OSA risk.