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What Is Pitted Keratolysis?

Medically Reviewed by Melinda Ratini, DO, MS on June 02, 2021

Pitted keratolysis is a skin infection that causes you to have small holes in the top layer of your skin. It usually affects the soles of your feet, but it can also happen to the palms of your hands.

This condition can cause itchiness and smelly feet. Read on to learn more about what it is, how it’s diagnosed, treatment, and more.

What Is Pitted Keratolysis?

Pitted keratolysis is a skin disorder that’s caused by bacteria. It creates crater-like pits or small holes on the top layer of your skin and usually affects the soles of your feet, but can also develop on the palms of your hands.

It’s more common in people who:

  • Often go barefoot and live in tropical areas
  • Wear occlusive shoes, which are shoes that create warm and moist environments for bacteria to thrive as they surround your feet

Symptoms

Symptoms of pitted keratolysis include:

  • Bad odor coming from the soles of your feet or the palms of your hands. This is the most common symptom.
  • Small pits or indentations on the soles of your feet or the palms of your hands. These tend to be round and are typically 0.5 millimeters to 7 millimeters in diameter.
  • Hyperhidrosis, which is excessive sweating that isn’t necessarily caused by heat or exercise.
  • Maceration, which is when your skin becomes lighter and more wrinkly due to prolonged exposure to moisture such as sweat. Maceration in pitted keratolysis is mostly due to hyperhidrosis.
  • Pain and itching while walking.
  • Slimy skin.

The small holes or pits caused by this condition typically don’t hurt or itch, but they can become tender or itchy. They can also have a burning sensation.

Research shows that pitted keratolysis is more likely to occur in men.

You may also be more likely to develop pitted keratolysis if you:

  • Are immunocompromised due to chemotherapy or other reasons
  • Are overweight
  • Have diabetes
  • Have poor hygiene

Causes

Pitted keratolysis can be associated with stinky feet and excessive sweatiness, but it’s not caused solely by sweating. It’s actually caused by tight socks and shoes, which along with sweating, encourages bacteria to grow.

The following kinds of bacteria are responsible for this condition:

  • Kytococcus sedentarius (formerly known as Micrococcus spp.)
  • Dermatophilus congolensis
  • Corynebacterium spp.

These bacteria grow on the sites of infection and break down the top layer of skin to create small holes or indentations. The strong odor is due to sulfur compounds made by bacteria as they break down the skin.

Diagnosis

Your doctor will look at your soles or palms to diagnose this condition. 

They may use a dermatoscope, which is a hand-held tool used to examine skin lesions, and look at your infection sites. If you have pitted keratolysis, your doctor will see many pits with well-marked walls. Sometimes, bacterial colonies can also be seen through the dermatoscope.

They may also order bacterial cultures to be taken. This can help them find out what kind of bacteria is causing your pitted keratolysis. 

Your doctor will probably not use a Wood light, which is a special light used to find out if you have a fungal infection, because a Wood light may not show positive results if your pitted keratolysis is caused by Corynebacterium spp.

Treatment

To treat pitted keratolysis, you will need to make certain lifestyle changes and use medication as needed.

Lifestyle changes. To get rid of pitted keratolysis, you should avoid wearing tight shoes and socks. Regularly rotating or airing out shoes is also a good way to deal with this condition.

Other lifestyle changes you should adopt include:

  • Don't share towels or shoes with others.
  • Use absorbent cotton socks.
  • Dry your feet properly every time you take a bath or wash your feet.

Medication. Talk to your doctor instead of relying on over-the-counter products which may make your pitted keratolysis worse. Many over-the-counter products contain antiperspirants, antifungals, or ointments that make maceration worse.

To treat your pitted keratolysis, your doctor may prescribe anti-bacterial creams and gels such as erythromycin, clindamycin, or mupirocin. 

If necessary, they may also prescribe drying agents such as Drysol. Botulinum toxin or iontophoresis may also be prescribed to treat sweating.

Treatment will depend on the severity of your pitted keratolysis. Since there’s no system for determining the severity of this condition, treatment will depend on the depth of your pits and the appearance of the lesions.

For instance, if you only have small pits and stinky feet, you may only need to apply erythromycin gel. If you have stinky feet along with deep pits, you may need the gel as well as another antibiotic. 

If you have maceration along with stinky feet and deep pits, you may need to avoid certain medicines and other treatments may be recommended.

Pitted keratolysis will typically go away after one to eight weeks of treatment.

WebMD Medical Reference

Sources

SOURCES:

American Osteopathic College of Dermatology: “Pitted Keratolysis.”

Canadian Medical Association Journal (CMAJ): “Pitted keratolysis: an infective cause of foot odour.”

Dermatology Reports: “Plantar pitted keratolysis: a study from non-risk groups.”

Medscape: “Pitted Keratolysis.”

National Library of Medicine (US). Roxithromycin. Drugs and Lactation Database, 2019.

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