Chilblains - Causes of chilblains

Chilblains are the result of an abnormal reaction to the cold.

During cold weather blood vessels near the surface of the skin get narrower, causing the blood to flow deeper in the skin. This is your body's normal response to cold and is designed to preserve your core body temperature.

When skin is exposed to warmth again, the blood vessels near the surface of the skin expand and blood flow returns to normal.

If skin is heated up too quickly, for example by placing your feet in hot water or near a heater, the blood vessels near the surface of the extremities, such as the hands and feet, cannot always handle the increased blood flow. 

This creates a "bottleneck" effect that can cause blood to leak into surrounding tissue. This is thought to be the reason for the swelling and itchiness associated with chilblains.

People at risk

Some people are more at risk of chilblains than others. This includes people with:

• poor circulation
• a family history of chilblains
• regular exposure to cold, damp or draughty conditions
• a poor diet or low body weight
• lupus – a long-term condition that causes swelling in the body's tissues
• Raynaud's phenomenon – a common condition that affects the blood supply to certain parts of the body, usually the fingers and toes

People who smoke are more at risk of chilblains as nicotine constricts blood vessels.

Chilblains can also occur on areas of the feet that are exposed to pressure, such as a bunion or a toe that is squeezed by tight shoes.