Embarrassing Illnesses

Chilblains occur when the small arteries and veins in the skin constrict (get narrower) as a result of cold weather. This is your body's normal response to cold (see box, right) and is designed to preserve your core body temperature.

However, when the body is exposed to sudden warmth after cold, the surface vessels on the extremities (such as hands and feet) cannot handle the sudden expansion and increased blood flow to the skin. Blood can leak into surrounding tissue and cause the swelling and irritation that is characteristic of chilblains.

At-risk people

Some people are more at risk of chilblains than others. They include:

• people with poor circulation
• people with a family history of chilblains
• people who are regularly exposed to damp or draughty conditions
• people who have a poor diet or low body weight 
• people with lupus, a long-term condition that causes inflammation (swelling) in the body's tissues 
• people with Raynaud's phenomenon, where the small blood vessels of the fingers constrict excessively
• people who smoke (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.