Chilblains

What are chilblains?

Chilblains (which also go by the medical name 'perniosis') are more common in older people, but anyone can be affected. They're most common in colder environments, especially when the climate is damp.

Causes and risk factors

Chilblains are caused by an abnormal response of the blood vessels to cold exposure, particularly when conditions are also damp or humid. The cold causes localised patches of intense swelling in the deeper layers of the skin, triggering the immune system cells to flood in around the blood vessels, which also become swollen.

Symptoms

Symptoms develop 12 to 24 hours after exposure to the cold. The extremities become very itchy, then swollen and red. Painful, burning reddish purple plaques or lumps form, and there may also be blisters and ulcers in more severe cases.

Treatment and recovery

Although a number of different medical treatments have been tried, there is little reliable evidence to show they work and so prevention is most important. This usually involves changing your behaviour. Many people rest their hands or feet against a radiator to warm them up when they're cold, but reheating rapidly like this can cause damage to tissues already stressed by the cold, and can trigger chilblains.

It's best to warm cold hands and feet up slowly. Alternating putting them in and out of warm water then cold water is one easy way of rewarming them safely. Another is by rubbing your wrists together to stimulate the circulation to the hands.

It's important to make sure your fingers and toes stay warm. So always carry a pair of cotton gloves with you, and long socks are probably better than short ones.

Regular exercise, not smoking and a healthy, low-fat diet are essential for strong circulation. Make sure your shoes fit well and feel comfortable. If they rub, the skin may become damaged or infected, making it more vulnerable to chilblain damage.

Some people develop frequent and severe chilblains, and need medication to keep the blood vessels open, maintaining blood flow to the extremities in the cold. Recurrent severe chilblains may also occasionally be a sign of an underlying condition such as connective tissue disorders (for example systemic lupus erythrematosus.)