How do we assess treatment efficacy in a pediatric patient with tinea capitis (ringworm of the scalp) presenting with a patch of missing hair but no inflammation, who is being treated with griseofulvin (antifungal medication) and ketoconazole (antifungal medication) shampoo?

Assessing Treatment Efficacy in Non-Inflammatory Tinea Capitis

The endpoint of treatment is mycological cure, not clinical appearance—you must obtain repeat fungal cultures until they are negative, regardless of whether the hair patch looks better or inflammation was never present. 1, 2

Why Clinical Appearance Alone Is Insufficient

The absence of inflammation does not indicate treatment failure or success in tinea capitis. 1 Your patient's presentation—a patch of missing hair without inflammation—is consistent with the "black dot" pattern typical of Trichophyton tonsurans endothrix infections, which are characteristically non-inflammatory. 1 This clinical pattern is expected and does not reflect treatment response.

The Definitive Treatment Endpoint

Mycological cure (negative microscopy AND negative culture) is the only acceptable endpoint for adequate treatment, not clinical improvement or hair regrowth. 1, 2 The British Association of Dermatologists explicitly states that repeat mycology sampling must continue until mycological clearance is documented. 1, 2

Monitoring Protocol During Treatment

• Obtain repeat fungal cultures at the end of the standard treatment period (6-8 weeks for griseofulvin). 1, 2
• Continue monthly mycology sampling until cultures are negative. 1, 2
• Use scalp scrapings, hair plucks, brush sampling, or swabs to collect specimens. 1
• All specimens should be processed for both microscopy (using 10-30% potassium hydroxide) and culture on Sabouraud agar for at least 2 weeks. 1

What "Working" Actually Means

Treatment efficacy is determined by:

• Negative direct microscopy (no hyphae or arthroconidia visible). 1
• Negative fungal culture (no dermatophyte growth after 2-3 weeks of incubation). 1
• These must both be negative on repeat testing, not just once. 1, 2

Clinical Improvement vs. Mycological Cure

If you see clinical improvement (reduced scaling, decreased alopecia patch size, or hair regrowth beginning) but mycology remains positive, continue the current therapy for an additional 2-4 weeks rather than stopping treatment. 1, 2 Clinical cure rates can exceed 90% while mycological cure rates may be substantially lower—this discrepancy is why culture confirmation is mandatory. 3

Common Pitfall to Avoid

Never stop treatment based on clinical appearance alone, even if the hair patch appears to be improving or inflammation resolves. 1, 2 The dermatophyte can persist in hair follicles despite clinical improvement, leading to relapse and continued transmission to others. 1, 4

Role of Ketoconazole Shampoo

The ketoconazole shampoo serves as adjunctive therapy to reduce surface arthroconidia and decrease transmissibility, but it does not replace the need for oral antifungal therapy or change how you monitor treatment success. 4 Shampoo alone reduces viable spores but cannot achieve cure in most cases—only 33% of children achieved complete cure with shampoo monotherapy in one study. 4

Expected Timeline for Mycological Clearance

With appropriate oral griseofulvin therapy for Trichophyton infections, you should see:

• Reduction in colony counts within 2 weeks (from confluent growth to <100 colonies). 4
• Further reduction by week 4 (<50 colonies) and week 6 (≤20 colonies). 4
• Negative cultures typically by 6-8 weeks in successfully treated cases. 1, 4

If cultures remain positive beyond 8 weeks despite clinical improvement, extend treatment for another 2-4 weeks before considering treatment failure. 1, 2