Acute onset of chilblains on cold exposure; marked by edema, itching, blue-red discoloration, and burning pain in initial stage, which lasts approximately 1 week. Lesions become brownish for several weeks to months, and ulceration and fibrosis may develop. Cause is reaction of peripheral blood vessels to cold. Treatment is avoidance of cold and (in severe cases) nifedipine and sympathectomy.