Pitted keratolysis (PK) is a common superficial bacterial skin infection primarily targeting the soles of the feet. It causes characteristic lesions on the outermost layer of the skin, the stratum corneum, most pronounced on weight-bearing areas. PK is prevalent in individuals who wear occlusive footwear, creating a warm, moist environment where the causative bacteria flourish. While easily treatable, its presence is often uncomfortable and can be a source of social embarrassment.
Answering the Primary Question About Pain
Pitted keratolysis is generally not painful, characterized more by discomfort and a distinct odor than by sharp sensation. Most individuals experience the infection as asymptomatic, where the only noticeable sign is the presence of the pits and the malodor. Some people report mild burning, tenderness, or itchiness in the affected areas, especially when walking or standing for long periods. Severe or sharp pain is rare and may suggest a secondary infection or a different dermatological issue. The most consistent symptom of PK is a strong, foul odor emanating from the feet, known medically as bromodosis.
Visual Symptoms and Appearance of Pitted Keratolysis
The condition derives its name from the numerous small, shallow depressions that appear on the skin’s surface. These circular, “punched-out” pits typically measure between 0.5 and 7 millimeters in diameter. The pits are most visible on pressure-bearing areas of the foot, such as the heel and the ball of the foot. When the skin is wet or sweaty (maceration), these pits become more pronounced. The affected skin may also appear slightly white, grayish, or have a slimy texture due to prolonged moisture. In severe cases, individual pits may merge, creating larger, irregular lesions on the sole.
Bacterial Cause and Environmental Triggers
Pitted keratolysis is caused by specific bacteria, most commonly species of Corynebacterium. Other bacteria, such as Kytococcus sedentarius and Dermatophilus congolensis, have also been identified as culprits. These organisms thrive in warm, moist, and occluded environments, strongly associating the condition with excessive foot sweating (hyperhidrosis). The bacteria produce proteinase enzymes that break down the keratin protein in the outermost layer of the skin. This enzymatic destruction of the stratum corneum creates the characteristic pits and shallow tunnels. As the bacteria metabolize the skin’s material, they release volatile sulfur compounds, such as thiols and sulfides, which are responsible for the intense, unpleasant foot odor.
Treatment and Moisture Management
Effective treatment for pitted keratolysis involves a dual strategy focused on eliminating the bacteria and rigorously controlling moisture. Topical antibacterial medications are the primary course of action prescribed by healthcare providers. These often include topical antibiotics like erythromycin, clindamycin, or mupirocin, typically applied twice daily for several weeks. Antiseptic agents such as benzoyl peroxide gel can also be used to reduce the bacterial load on the skin.
Concurrently, strict moisture management is essential to treat the existing infection and prevent future recurrences. This involves lifestyle modifications like avoiding tight or non-breathable footwear that traps heat and sweat. The regular use of absorbent powders and changing socks frequently is highly recommended to keep the feet dry. For individuals with significant hyperhidrosis, strong antiperspirants containing aluminum chloride can be applied to the feet to reduce excessive sweating. Washing the feet daily with an antibacterial soap and ensuring they are thoroughly dried, including between the toes, is a fundamental hygiene practice for successful long-term management.