Pernio (chilblains).

Pernio is a vasospastic disorder that affects unprotected skin regions of individuals exposed to nonfreezing, damp cold. It may be idiopathic or associated with other systemic diseases, particularly cryopathies and lupus erythematosus. Acute pernio manifests several hours following exposure, whereas chronic pernio may persist even after the cold season has long ended. The pathophysiology is complex and related to patient and environmental factors. Pernio is diagnosed by clinical features. There are no characteristic histopathologic features that confirm the diagnosis, but biopsy of affected areas may exclude the presence of other disorders. Sequelae include superinfection, depigmentation, and scarring. Treatment involves rewarming of the whole body and avoidance of further exposure to cold. The use of the dihydropyridine calcium channel blocker nifedipine promotes faster healing and prevents recurrence.