Pitted Keratolysis: Symptoms, Causes, and Treatment in the UK

Pitted keratolysis is a common, though often under-diagnosed, superficial bacterial infection that affects the stratum corneum (the outermost layer) of the skin on the soles of the feet. In the UK, it is frequently seen in individuals who wear restrictive, non-breathable footwear for long periods, such as construction workers, athletes, and military personnel.

The condition is characterised by the appearance of numerous small, circular pits or craters on the weight-bearing areas of the feet, such as the heels and the balls of the feet. These pits can coalesce into larger, eroded areas. While it is rarely painful, the most distressing symptom for many patients is the persistent, pungent odour that does not resolve with standard washing.

The primary culprits behind pitted keratolysis are bacteria such as Kytococcus sedentarius, Dermatophilus congolensis, and species of Corynebacterium. These bacteria thrive in 'occlusive' environments—where the skin is kept warm and damp.

Why Does it Happen?

• Excessive Sweating (Hyperhidrosis): Sweat softens the skin (maceration), making it easier for bacteria to proliferate and produce enzymes that digest the keratin in the skin, creating the characteristic pits.
• Footwear Choices: Wearing rubber boots, tight trainers, or synthetic socks prevents moisture from evaporating.
• Occupational Risks: People who work long shifts in boots or walk long distances are at higher risk.
• Warm Climates: While common in the UK during humid summer months, it is a year-round issue for those with naturally sweaty feet.

Many people mistake pitted keratolysis for a fungal infection like athlete's foot (tinea pedis). However, the appearance and symptoms are distinct. Key features include:

• The Pits: Small indentations ranging from 1mm to 7mm in diameter. These often appear more pronounced when the feet are wet.
• Discolouration: The affected areas may look white, slimy, or slightly brownish.
• Odour (Bromhidrosis): A strong, 'cheesy' or vinegar-like smell caused by sulfur compounds produced by the bacteria.
• Sensation: Most cases are asymptomatic, but some patients report a slimy feeling when walking or occasional itching and soreness if the erosions become deep.

Treatment for pitted keratolysis focuses on two goals: eliminating the bacteria and keeping the feet dry. According to clinical guidance, the following approaches are most effective:

Topical Antibiotics

Prescription-strength topical antibiotics are the first line of treatment. A GP will typically prescribe Clindamycin or Erythromycin in a solution or gel format. Fucidin (fusidic acid) or Mupirocin may also be used. These are applied twice daily to the clean, dry soles of the feet for two to four weeks.

Managing Hyperhidrosis

If sweating is the underlying cause, treating the perspiration is vital to prevent recurrence. Over-the-counter antiperspirants containing aluminium chloride (such as Driclor or Anhydrol Forte) can be applied to the soles at night.

Foot Hygiene Measures

• Wash feet twice daily with an antiseptic wash or mild soap.
• Dry feet thoroughly, paying particular attention to the areas between the toes.
• Wear moisture-wicking socks made of wool or cotton, rather than synthetic materials.
• Rotate footwear daily to allow shoes at least 24 hours to dry out completely.

If you have noticed small holes in the skin of your feet accompanied by an odour that won't go away, it is time to seek medical advice. Because the condition is visible, it is highly suited to an online GP consultation. You can often upload high-resolution photos of your feet, allowing a doctor to diagnose the condition accurately without you needing to travel to a clinic.

You should speak to a GP if:

• Over-the-counter antifungal treatments for athlete's foot have failed (as these do not kill the bacteria responsible for pitted keratolysis).
• The skin on your feet is becoming increasingly sore or painful.
• The odour is causing significant distress or affecting your social life.
• You have a pre-existing condition like diabetes, where any foot infection requires professional monitoring.

Through OnlineDoctor24, you can receive a private prescription for the necessary antibiotic gels, which can be sent directly to a local pharmacy for collection, ensuring you start treatment quickly.

Once the bacterial infection has cleared, maintenance is key. Pitted keratolysis has a high rate of recurrence if the moist environment is not corrected. We recommend avoiding occlusive footwear whenever possible—for example, wearing sandals or open-toed shoes when at home. If your job requires boots, consider using boot dryers overnight and changing your socks halfway through a shift. Regular use of foot powders can also help absorb excess moisture throughout the day.