Haywan Chiu, DPM, is a practicing podiatrist in Albuquerque, New Mexico. He has a special interest in the diabetic foot. Haywan runs Diabetic Foot Guardian, an easily digestible resource for patients regarding feet and diabetes.
Callus Debridement Can Be Diagnostic
Calluses form when shear forces and pressure induce the epidermis to reinforce itself. In patients with diminished pain sensation such as in diabetic neuropathy, continued friction from shear forces and pressure evolves the callus into a blister, then a blood blister (figure 1). When I see a bloody foot callus, I know that at some point, there was a break in the dermis. I don’t know if it has healed on its own or if it has expanded into a full blown ulcer because I can’t see past the callus. In fact, some calluses can be so thick I can’t even see the blood underneath! The only way to find out what’s hiding is to debride the callus.