Benzoyl Peroxide for Pitted Keratolysis: Did 5% Beat 2.5%?

If a clinician recommends benzoyl peroxide for pitted keratolysis, a higher percentage on the tube may seem like a faster route to improvement. The direct concentration comparison provides a reason to ask what the stronger product would add.

The concentration trial compared two active gels

Researchers at a Thai naval rating school assigned cadets with pitted keratolysis to 2.5% or 5% benzoyl peroxide gel, applied to each sole once daily for two weeks. The analysis included 42 participants receiving 2.5% and 47 receiving 5%.¹

Dermatologist-rated lesions improved in 69.0% versus 63.8%, respectively, without a significant difference (P = 0.457). Self-rated odor decreased in both groups. Reported side effects also did not differ significantly.¹

The lesion figures describe improvement, not complete clearance. With no placebo group, the trial cannot quantify the benefit over the gel base or no treatment. Its accessible abstract supplies neither a precise odor advantage between concentrations nor evidence of lasting prevention. The full original methods were unavailable for this article.¹

The antibiotic comparison was small and mostly involved men

An older study described 44 patients: 43 men and one woman. Seventeen received benzoyl peroxide, 15 clindamycin phosphate and 12 a combination. The author university’s abstract reports no significant efficacy difference between the individual treatments or between single and combined treatment.²

Four patients had irritation, two associated with each individual medication. Four had recurrence during three months of follow-up, all associated with excessive sweating. Those small numbers cannot establish that the treatments have identical recurrence risks.²

The abstract does not establish random allocation. It should not be presented as a large randomized comparison or used to justify adding an antibiotic automatically.²

The wider evidence does not identify a winning concentration

A 2025 systematic review found that much of the treatment literature consisted of case reports and small series, with inconsistent definitions of full resolution, partial improvement and treatment failure. Its table identifies the concentration trial’s participants as male.³

A successful case report of a combined antibiotic and benzoyl peroxide product cannot show which ingredient helped, whether the combination outperforms either ingredient or how often the result occurs. The review calls for better controlled studies. Its proposed treatment algorithm is not evidence that one concentration has won a direct comparison.³

For a woman considering treatment, the limited female participation is another uncertainty to discuss. It does not mean treatment cannot help; it limits how specifically these studies can predict her result.

Confirm the condition and the product before treating odor

DermNet⁴ describes pitted keratolysis as a bacterial infection, usually affecting pressure-bearing areas of the soles. Its treatment options include topical antibiotics and antiseptics, with benzoyl peroxide used alone or alongside an antibiotic. Skin scrapings may help exclude a fungal infection when the diagnosis is uncertain.⁴

Odor alone does not establish that diagnosis. Ask the clinician to specify the product’s form, concentration, application instructions and review date. The concentration trial tested gel; it does not establish that a briefly rinsed acne wash produces the same result.

MedlinePlus’s⁵ benzoyl peroxide information is written for acne, so its acne response timeline should not be substituted for a foot-infection plan. It warns about dryness and peeling, bleaching of hair and colored fabrics, and more serious reactions including blistering or swelling. Stop use and seek immediate help for throat tightness, difficulty breathing, faintness or swelling of the face or tongue.⁵

Keeping feet drier belongs in the discussion too. DermNet⁴ advises changing absorbent socks, avoiding prolonged use of occlusive footwear, rotating dry insoles and addressing excessive sweating. These measures support the treatment plan; they do not turn a concentration comparison into proof of permanent prevention.⁴

Chapter 7, “Sole Searching,” in Arms Up distinguishes ordinary foot odor, pitted keratolysis and athlete’s foot. Use that distinction at the appointment, and record odor, visible pits and discomfort separately so “better” has a clear meaning at review.