Pitted keratolysis is a bacterial skin infection that can affect both the soles of your feet and the palms of your hands. For this reason, it’s also known as holes in the feet, holes in the skin, and holes in the hand.

Here are its defining characteristics:

  • It most often affects the feet.
  • It causes small depressions, or pits, especially in pressure-bearing areas
  • It can be a cause of smelly feet and is more common in men than women, according to 2012 research.

We explain how to spot pitted keratolysis, why it happens, and how to get treatment if you discover symptoms.

Pitted keratolysis is usually asymptomatic. However, when you do have symptoms, the most common effect is a noticeable odor from the feet. This is due to the skin infection on the bottom of the feet.

Other symptoms include:

  • Small holes in the skin. Those with this condition will usually have clusters of “punched-out” pits on the soles of their feet or the palms of their hands. Most often, these lesions appear on the pressure points of the soles. The pits will be more noticeable when the skin is wet.
  • Larger lesions. Sometimes these pits can join together, or coalesce, to form larger lesions.
  • Redness. In one type of pitted keratolysis, the affected areas of the skin turn red.
  • Itching and soreness. While the pits themselves usually won’t occur with other symptoms, they may sometimes feel sore or itch when you put pressure on the foot while walking.

Pitted keratolysis takes on the following appearance:

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Pitted keratolysis is an infection usually seen on the foot that causes punched-out lesions on the skin and smelly feet.
Evan Saap, CC BY-SA 4.0, via Wikimedia Commons

Several different bacterial species can cause pitted keratolysis. The most common are:

  • Corynebacteria
  • Dermatophilus congolensis
  • Kytococcus sedentarius
  • Actinomyces
  • Streptomyces

These bacteria often multiply in wet or moist conditions. Pitted keratolysis often develops when people don’t let their feet air out enough.

The bacteria on the feet or palms will produce protease enzymes that destroy the outermost layer of the epidermis. This causes the characteristic pitting. The odor comes from the bacteria’s production of sulfur compounds.

If you think you have pitted keratolysis, contact a healthcare professional. To diagnose pitted keratolysis, a doctor will swab the area or perform a procedure called skin scraping.

During a skin scraping, the doctor obtains a sample of skin to check for bacteria and parasites under a microscope. After identifying the pathogen, they can recommend the appropriate antibiotics for treating this bacterial infection.

To treat pitted keratolysis, your doctor will most likely prescribe a topical antibiotic or antiseptic, most commonly:

  • clindamycin
  • erythromycin
  • mupirocin

Doctors also recommend that you avoid tight-fitting socks and shoes. In rare cases, your doctor may suggest a drying agent like Drysol.

In extreme cases, your doctor may recommend shots of botulinum toxin (Botox) to treat the condition. This can help reduce sweating.

Because this bacterial infection thrives in moist environments, it’s important to keep your feet as dry as possible to prevent pitted keratolysis.

Take the following precautions to keep feet healthy and dry:

  • Wear shoes for as little time as possible.
  • Wear socks made of moisture-wicking materials, such as polyester and nylon.
  • Wear open-toed sandals as frequently as possible.
  • Wash your feet frequently with antiseptic cleanser.
  • Avoid sharing footwear with others.

The outlook for pitted keratolysis is excellent, as it is easy to treat and prevent.

By using topical antibiotics and other precautions, this condition will usually clear up in about 3 to 4 weeks.