What are chilblains?

Chilblains are itchy and/or tender red or purple bumps that occur as a reaction to cold. Chilblains are also known as pernio or perniosis. They are a localised form of vasculitis.

Severe cold injury can also damage the small bones in the digits, leading to microgeodic disease, swelling and sometimes, bone fracture.

Who gets chilblains?

Chilblains most often affect children and the elderly in damp, temperate climates.

• Chilblains in children may recur each winter for a few years and then clear up
• Chilblains in elderly people have a tendency to get worse every year unless precipitating factors are avoided
• Chilblains can be associated with systemic lupus erythematosus (chilblain lupus).

Perniosis

Perniosis

Perniosis

Microgeodic disease

Perniosis

Perniosis

What is the cause of chilblains?

Chilblains occur several hours after exposure to the cold. Cold causes constriction of the small arteries and veins in the skin. The chilblains are sometimes aggravated by sun exposure because rewarming results in leakage of blood into the tissues and swelling of the skin.

Chilblains are less common in countries where the cold is more extreme because the air is drier and people have specially designed living conditions and clothing.

Chilblains are more likely to develop in those with poor peripheral circulation, noted by blue-red mottled skin on the limbs (acrocyanosis).

Virus-induced type I interferonopathy (a higher than normal IFN-α response) has been associated with chilblains in COVID-19 infections and genetic type I interferonopathies.

Contributing factors

Other factors contributing to chilblains include:

• Familial tendency to chilblains
• Peripheral vascular disease, due to diabetes, smoking, hyperlipidaemia
• Low body weight, or malnutrition, for example, anorexia nervosa
• Hormonal changes: chilblains can improve during pregnancy
• Connective tissue disease, particularly lupus erythematosus (chilblain lupus), or, in association with Raynaud phenomenon, and systemic sclerosis
• Bone marrow disorders
• Viral infection; chilblains or chilblain-like lesions have been associated with asymptomatic or mild COVID-19 [1].

What are the clinical features of chilblains?

Each chilblain comes up over a few hours as an itchy red swelling and subsides over the next 7–14 days or longer. In severe cases, blistering, pustules, scabs and ulceration can occur. Occasionally the lesions may be ring-shaped. Chilblains may become thickened and persist for months.

Common sites for chilblains are:

• Backs and sides of the fingers and toes
• Heels
• Lower legs
• Thighs
• Wrists of babies
• Over a fatty lump (lipoma)
• Nose
• Ears.

What is the treatment of chilblains?

Chilblains respond poorly to treatment. The following may be useful:

• Topical corticosteroid cream applied accurately for a few days to relieve itch and swelling
• Oral antibiotics for secondary bacterial infection.

Can chilblains be prevented?

People with a tendency to chilblains must keep their hands and feet warm to reduce the risk of chilblains.

• Nicotine constricts the blood vessels, so smokers must stop smoking.
• Home and workplace should be well insulated without draughts and heated in winter.
• Warm clothing should include gloves, thick woollen socks and comfortable protective footwear.
• Cotton-lined waterproof gloves are protective for wet work.
• Soaking hands in warm water for several minutes warms them for up to several hours.
• Vigorous indoor exercise keeps the body warm for a period afterwards.
• Medicines that constrict blood vessels should be minimised, including caffeine, decongestants and diet aids.
• Vasodilator medications such as nifedipine are taken throughout the winter months. Side effects may include flushing and headache.