Chilblains

Chilblains — perniosis — happen when small blood vessels in the skin react abnormally to cold and then to rewarming. The vessels constrict in the cold and, when warmed too quickly, leak fluid into the surrounding tissue.

They are common in Delhi winters, particularly in homes without central heating where people warm cold hands and feet quickly against a heater or in hot water.

What they look and feel like

Red or purple patches on the fingers, toes, and sometimes the nose or ears. Itching and burning that is characteristically worse as the area warms up. Swelling, and occasionally blistering or skin breakdown in more severe cases.

Prevention, which matters more than treatment

• Rewarm gradually. This is the single most important point. Do not put cold hands or feet directly on a heater, in hot water, or against a hot water bottle
• Keep extremities insulated and dry — layered gloves and socks rather than one thick pair
• Keep the whole body warm, since the body prioritises core temperature and reduces blood flow to the extremities when cold
• Keep moving to maintain circulation
• Avoid smoking, which constricts small blood vessels

Managing them once present

Keep the area warm, dry and protected. Do not scratch. Do not apply direct heat. Moisturise to prevent skin cracking. Individual lesions settle over one to three weeks.

When to see a doctor

Chilblains that ulcerate, become infected, appear outside cold weather, or are severe and recurrent should be assessed medically — persistent or atypical chilblains can be associated with underlying circulatory or autoimmune conditions. People with diabetes or peripheral vascular disease should have any skin breakdown on the feet reviewed promptly.