What causes chilblains on the feet?

Chilblains are lesions that occur on the foot that are more common in the colder climates. Understanding the cause of any condition goes a long way to help understanding what is happening with them, how to prevent them and how to treat them. This is certainly true of chilblains. While they only occur in cold climates, they are not really caused by the cold. A lot of people who do not get them get cold as well and they do not develop chilblains. Similarly, some people develop chilblains with even small changes in temperature and it not being too cold. This means that there is a lot more going on than just the cold that usually gets blamed for causing chilblains.

In the skin there are a lot of small blood vessels (the microcirculation) that help regulate temperature in the body. When we become cold, those blood vessels constrict to conserve heat deeper in the body. When we are warm, those blood vessels open up and bring the blood closer to the surface so that we can dissipate heat to cool the body. This is an important normal function. In a chilblain the blood vessels close up like they normally should, but when the foot is warmed, the blood vessels stay closed when they should not. This means that waste products start to build up in the skin and there is no blood supply to remove them. This causes an inflammatory reaction and the release of chemical makes the chilblain painful and itchy. Eventually the blood vessels do open up and the sudden rush of blood to the chilblains causes further irritation and pain. The initial appearance is a dark bluish lesion, but t can be a reddish appearance after that rush of blood. If this process is repeated on a daily basis, then they can become quite a chronic lesion.

Just why in some people they stay closed for longer in colder climates in not known. Chilblains are more common in females, suggesting that there might be some sort of hormonal influence on the process. However, males do also get chilblains, so if it is hormone related, then that is not the only factor. Surprisingly for something that is so common, there is relatively little research been done to try and look into this further.

Using this knowledge of the cause can help people prevent and treat chilblains. Obviously the first thing to do is not let the feet get cold and keep them warm. If they do become cold, then it is crucial that they are warmed up very slowly so that the microcirculation has a chance to respond to the increased demand in the tissues and the blood vessels can open up to meet that demand. This means that the waste products do not build up and the inflammation process is not started. Once that process has started, then the treatment process has to move to limit that inflammation process and help get rid of those waste products that have accumulated in the skin.

Craig Payne is a University lecturer, runner, cynic, researcher, skeptic, forum admin, woo basher, clinician, rabble-rouser, blogger and a dad.