**Pathogenesis
It occurs as an abnormal reaction of body to cold exposure followed by rewarming. Increased blood viscosity results in sluggish blood flow through superficial vessels, which are already under spasm. Rewarming of skin causes exudation of fluid into surrounding tissue.
**Risk factors
Women are more susceptible
History of Raynaud's disease
May be associated with lupus, leukemia and poliomyelitis.
**Signs and symptoms may include
Localized doughy erythematous swelling in areas exposed to cold specially on dorsal aspect of proximal phalanges of fingers and toes, lower lip , heels and ear within 12 - 24 hours after exposure to cold.
**Severe itching
May be associated with burning sensation
Changes in skin color from red to dark blue
May be accompanied by pain
** Complications
Associated with blistering and ulceration in severe cases
Chronic Pernio- in presence of arterial and systemic disease , it may lead to irreversible changes such as hyperkeratosis , lymphedema and scarring.
**Treatment
Acute lesions are mostly self-limiting. The treatment mainly consists of proper clothing and heating.
Avoid or limit exposure to cold
Cover all exposed areas
Keep hands, feet and face dry, clean and warm.
Phototherapy with UV light may be beneficial.
Antipruritic lotion or topical steroid cream may provide symptomatic relief.
Nifedipine may be used in severe cases.
( With inputs from IANS )