Pitted keratolysis (PK) is a common superficial skin infection primarily affecting the soles of the feet. It is characterized by small, crater-like pits in the skin and a notably intense, foul odor. This condition arises from the overgrowth of specific bacteria in the perpetually warm and moist environment created by occlusive footwear and excessive sweating. While the pits are the physical sign of the infection, the overwhelming smell is often the primary symptom that prompts individuals to seek treatment.
Describing the Pitted Keratolysis Odor
The smell associated with pitted keratolysis is distinct and significantly more pungent than typical foot odor (bromodosis). The odor is consistently described as foul and can be overwhelming in enclosed spaces. Due to its chemical composition, the odor often carries notes reminiscent of sulfur, decay, or strong, aged cheese.
This intense malodor is a direct result of the bacterial activity on the skin. Unlike mild foot smells, the PK odor often persists even after basic hygiene because the source is a bacterial infection within the skin’s outermost layer. The smell is particularly noticeable and intensifies when the affected feet are damp, such as immediately after removing shoes and socks that have trapped moisture and sweat.
How Bacteria Create the Distinctive Smell
The offensive smell is a metabolic byproduct of the bacteria that cause the infection, primarily species such as Kytococcus sedentarius and various Corynebacterium species. These organisms thrive in the alkaline, saturated environment of sweaty feet, which provides the perfect incubator for their growth. Once established, the bacteria produce enzymes called proteinases, which act to degrade the keratin protein found in the stratum corneum, the outermost layer of the skin.
The degradation of keratin and other proteins in the skin releases specific sulfur-containing compounds, which are the true source of the smell. These volatile organic compounds include thiols, sulfides, and thioesters, known for their sulfurous or rotten-egg-like odors. The bacterial action produces the malodor and causes the characteristic small pits as they digest the skin’s surface layer.
Eliminating the Condition and Associated Odor
Eliminating the odor requires a two-pronged approach that targets both the bacterial infection and the excessive moisture that allows it to flourish. Medical treatment typically involves the application of topical antibiotics directly to the affected skin to kill the causative organisms. Common prescriptions include solutions or gels containing clindamycin, erythromycin, or fusidic acid, which are generally applied twice daily for several weeks.
In addition to antibiotics, topical antiseptics like benzoyl peroxide wash can be used to further reduce the bacterial load on the feet. Controlling hyperhidrosis, or excessive sweating, is also paramount to prevent recurrence. This can be achieved through the use of strong antiperspirants, such as those containing aluminum chloride solution, which help to dry the skin and make the environment less hospitable for bacteria.
Simple hygiene practices are necessary for long-term relief and prevention.
Hygiene Practices
- Wash feet thoroughly with soap and water, ensuring they are completely dry afterward, especially between the toes.
- Wear moisture-wicking or absorbent cotton socks.
- Change socks frequently, sometimes multiple times a day.
- Rotate footwear to allow shoes to dry out completely, which can take up to 24 hours.