Calluses are thick skin that forms in response to repeated pressure over a course of time. Blisters are fluid filled pockets that are also the result of increased pressure but typically the pressure is more intense and for a shorter period of time than the pressure that causes a callus. The roof of a blister is typically very thin because there is not enough time to form a thick callus. Calluses form over pressure points to protect the skin from injury. Without calluses the skin is more prone to blisters.

If calluses are protective then why is there so much concern about calluses on the soles of a person with diabetes?

Calluses form to protect the skin; however, in persons with diabetes the body does not know how much callus to lay down and the callus is different. Elevated blood sugars affect the skin and cause thicker and harder calluses.

Heavier calluses combined with peripheral neuropathy or feeling loss can cause sores. As the callus builds up, it can cut off the blood supply to the skin below and damage the skin. The result can be a sore or an ulcer.

The pressure that causes callus formation can also cause bleeding. It is not uncommon to see dark spots of dry blood in callus. In a person with diabetes and neuropathy it is thus very important to have the calluses trimmed regularly so that they do no build up and cause bleeding or sores.

Untreated calluses and blisters are dangerous because they can become infected and/or turn into non-healing wounds. Persons with diabetes are prone to infection and delayed wound healing.

What steps can I take to protect my feet from blisters and heavy calluses?

Calluses should be treated regularly by a professional. Persons with diabetes should not attempt to trim their own calluses. Professional care should include callus trimming, as well as, a discussion on the cause of the callus and a plan to slow down recurrence.

Daily self foot inspection of the feet to check for things like calluses or blisters is of utmost importance for a person with diabetes and of even more importance for a person with diabetes and neuropathy (feeling loss). Pain is a form of protection. Without pain a person won’t be able to feel if the callus is causing injury or if a blister is forming.

Tips for blister and callus protection include: professionally fitted shoes, pumice stones, protective insoles or orthotics, daily self foot examinations and regular trips to a foot health care provider.

The frequency of visits should be decided on an individual basis. Some, but not all, foot creams are safe and beneficial. Creams should also be selected on an individual basis. Persons with diabetes should check with their foot health care provider before using a cream.