Pitted keratolysis (PK) is a common superficial skin infection affecting the soles of the feet, characterized by numerous small depressions in the skin. It is caused by bacteria that thrive in warm, moist environments, leading to noticeable skin changes and a distinct, unpleasant foot odor. While pits and odor are the most recognized features, the physical sensation—whether it is painful or merely uncomfortable—is a frequent question. This article clarifies the experience of discomfort versus pain and outlines treatment and prevention strategies.
The Bacterial Cause of Pitted Keratolysis
Pitted keratolysis is caused by the overgrowth of specific bacteria, most commonly species like Corynebacterium and Kytococcus sedentarius. These microorganisms colonize the outermost layer of the skin, the stratum corneum, flourishing in environments with excessive moisture, or hyperhidrosis. This is often exacerbated by wearing occlusive footwear for long periods. The bacteria produce protein-degrading enzymes (proteinases) that break down the keratin protein, creating the characteristic crater-like pits. The foul odor associated with PK is a direct byproduct of this activity, resulting from the production of sulfur compounds such as thiols and sulfides.
Identifying Symptoms and Addressing the Pain Question
The primary visual symptom of PK is the appearance of numerous small, punched-out craters on the sole of the foot. These lesions are most frequently concentrated on pressure-bearing areas, such as the heels and the balls of the feet. When the skin is wet, the pits often become more pronounced, and the surrounding area may appear white and macerated. The most common complaint associated with the condition is the strong, pungent foot odor rather than acute physical pain.
Pitted keratolysis is generally asymptomatic of true pain because the bacterial activity is confined to the non-living outer layer of the skin. However, patients frequently report tenderness, a burning sensation, or itchiness, particularly when walking or standing for extended periods. This physical sensitivity arises because the structural integrity of the skin is compromised by the pitting. The tenderness is a result of the pressure exerted on the compromised skin layer during weight-bearing activities.
Treatment and Preventing Recurrence
Treatment
Managing Pitted Keratolysis requires targeting the bacterial infection and addressing the underlying cause of excessive moisture. A healthcare provider typically prescribes topical antibiotics, such as clindamycin or erythromycin, applied directly to the affected areas. Topical benzoyl peroxide is also an effective antiseptic agent that may be used alone or combined with antibiotics to clear the infection.
Prevention
Long-term prevention focuses on reducing the moist environment where the bacteria thrive. This involves several key steps:
- Practicing meticulous foot hygiene, including washing feet daily and drying them thoroughly, especially between the toes.
- Wearing moisture-wicking socks, which are superior to cotton, and changing them at least once or twice daily, or whenever they become damp.
- Rotating footwear, allowing shoes to dry completely for at least 24 hours before being worn again.
- Applying antiperspirants containing aluminum chloride to control excessive sweating (hyperhidrosis), which is a major factor in recurrence.