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.

Perniosis is thought to be caused by an abnormal response of the blood vessels to cold temperatures. In some instances, perniosis can occur in an individual for a long time and/or may be recurring. In these cases, the condition could be related to an underlying disease including:

• Certain cancers such as chronic myelomonocytic leukemia and Waldenstrom macroglobulinemia 
• Eating disorders, such as anorexia nervosa
• Abnormalities of the protein content in the blood (dysproteinemias)
• Cold agglutinin disease
• Antiphospholipid antibody syndrome
• Raynaud disease 
• Celiac disease 
• Viral hepatitis

The main method of treatment for perniosis focuses on avoiding exposure to cold. Individuals with this condition may be advised to keep the affected areas of their body warm by wearing insulated clothing, gloves, and footwear. The use of ultraviolet light at the beginning of cold, damp season may help prevent outbreaks. It is also suggested that people with this condition do not use cigarettes or nicotine. The use of certain medications, such as topical steroids and nifedipine, a calcium channel blocker, have been effective in treating some individuals.