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.
Technique, Tips, and Tricks
| Figure 5. Take multiple slices and “chase the bump” until you get down to the level of normal adjacent epithelium. |
I got started by debriding an orange at home in my early training. Consider asking a foot specialist for supervision. Think of the callus as a small bump, and take slices or scrapes parallel to the skin until you get down to the level of normal skin. At first, you want to take as thin a slice as possible. After every 2-3 slices, feel the callus with your thumb to get an idea of how much callus tissue remains. It is easier build a mental image of the callus by feel rather than by look, because hyperkeratotic epidermis can vary in transparency.
As a safety precaution, understand that dull blades are much more dangerous than sharp blades. As the blade dulls, it becomes harder to control and you need to use more force to get through the tissue, thus increasing your chances of slipping and cutting yourself. Use as many fresh blades as you need to get the job done safely.
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| Figure 6. Take thin slices of tissue using the blade. || Figure 7. Use a dermal curette to scrape away at the tissue. |
Check out the full article for more on calluses and osteomyelitis, tools of the trade, and iatrogenic injury.