Perniosis are itchy and/or tender red or purple bumps that occur as a reaction to cold. In severe cases, blistering, pustules, scabs and ulceration may also develop. Occasionally, the lesions may be ring-shaped. They may become thickened and persist for months. Perniosis is a form of vasculitis. Signs and symptoms occur hours after cold exposure. Risk factors for perniosis include having poor blood circulation (such as due to diabetes or smoking), a family history of perniosis, poor nutrition, and low body weight. Perniosis may occur alone or in association with an autoimmune condition (e. g. , lupus, scleroderma), bone marrow disorder, or cancer. Treatment aims to relieve symptoms and prevent infection. Lifestyle/adaptive changes may also be recommended to prevent future symptoms. 
What is (are) Perniosis ?