Chilblains

What are chilblains, and how common are they?

Chilblains (also called pernio or perniosis) are an abnormal reaction of the skin's small blood vessels to cold, damp conditions¹. They cause red or purple swellings that itch or hurt, usually on the toes and fingers, though they can appear on other areas¹. Cold, wet weather that stops short of freezing is what brings them on, and they usually clear up by themselves².

Chilblains are described as an uncommon condition³.

What causes chilblains, and who gets them?

Chilblains come from the skin's abnormal reaction to cold⁴. When it is cold, the tiny blood vessels in the fingers and toes can stay narrowed for longer than they should, which cuts the amount of blood getting through, and wet and windy weather can intensify this¹. Damp or draughty living conditions may also play a part, and so can chilling followed by warming up too quickly, for example in front of a fire or hot water bottle⁵.

They're seen more often in colder climates⁴.

What do chilblains look and feel like, and how are they diagnosed?

Chilblains typically show as itchy or painful red, purple or blue patches or swellings on the toes and fingers, often on both sides of the body, and less often on the heels, nose or ears⁴. They often start in winter⁴. The smaller toes are common spots⁵. The skin can swell and then dry out and crack, which raises the risk of infection⁵. On brown and black skin, redness can be harder to see, so look for purple or swollen areas as well⁶.

A podiatrist or GP will usually ask when the patches appeared, whether they followed the cold and whether they return each winter, and will look closely at the skin. Occasionally other conditions look similar⁴, which is one reason patches that appear without cold, or for the first time later in life, are treated as needing medical review¹.

What can I do first?

Most people don't need medical advice for chilblains⁷. The main step is to rewarm slowly after being cold⁸. Warming up too fast with a radiator, hot water bottle or hot water is best avoided⁹. Try not to scratch or pick at itchy chilblains⁹.

If a chilblain has broken open (ulcerated), cover it straight away with a sterile dressing, which you can buy at a pharmacy, and check it daily for signs of infection¹⁰. A podiatrist or GP can look at it and advise on care.

What helps if that isn't enough?

If self-care isn't enough, a GP can look for other causes and decide whether a medicine is suitable for you. Medicines for chilblains should be prescribed and reviewed by a doctor, who weighs up the benefits and harms for each person. It isn't clear yet how well any particular medicine works. Slow rewarming and avoiding scratching remain the first-line measures.

How long do chilblains last, and how can I stop them coming back?

Most chilblains clear up without treatment within 2–3 weeks⁶. Symptoms tend to begin in winter, usually ease by spring, and frequently come back each year⁴. Older people, and people with venous insufficiency (poorly working leg veins), may have a longer course⁴. If your circulation is poor, chilblains may last several weeks and are more likely to become open wounds if you don't look after them⁹.

To lower the chance of them coming back, try to rewarm slowly after the cold rather than using direct heat⁸. Smoking and caffeine can affect blood flow in the fingers and toes⁶, and smoking may slow healing⁹, so cutting back is worth considering. It isn't clear yet how much any of these steps reduces how often chilblains return.

What can make it serious?

Chilblains that are severe, haven't improved after 2–3 weeks, or keep coming back; that blister, break down or are painful; that happen without cold exposure; or that first appear later in life can be signs that the condition is more serious¹⁶.

Signs of infection around a chilblain include swelling and pus in the affected area, a fever of 38°C or above, swollen glands, or feeling generally unwell⁷. In people with diabetes or those undergoing medical treatment, a chilblain that has broken open is more of a concern, and a new sore, blister or colour change on the foot in someone with diabetes may signal a developing problem⁹. People with diabetes may not feel an infected chilblain, so check your feet regularly⁷.