When do you stop griseofulvin (antifungal medication) in a young child with topical treatment resistant tinea corporis (fungal infection of the body) when the lesions disappear?

When to Stop Griseofulvin for Topical Treatment-Resistant Tinea Corporis in Young Children

Do not stop griseofulvin when the lesions disappear clinically—continue treatment until mycological cure is documented, which typically requires 2-4 weeks of therapy for tinea corporis, with confirmation by repeat microscopy or culture showing clearance of the organism. 1

Treatment Duration Guidelines

Standard Treatment Course

• The FDA label specifies 2-4 weeks of treatment for tinea corporis, regardless of when clinical lesions resolve 1
• The British Association of Dermatologists emphasizes that the definitive endpoint for treatment should be mycological cure, not just clinical response 2
• Treatment must continue until the infecting organism is completely eradicated as indicated by appropriate clinical or laboratory examination 1

Why Clinical Clearance Is Insufficient

• Clinical relapse will occur if medication is not continued until the infecting organism is eradicated 1
• Stopping treatment when lesions disappear visually often leads to recurrence because viable fungal elements remain in the skin even after inflammation resolves 2
• The British Journal of Dermatology strongly recommends follow-up with repeat mycology sampling until mycological clearance is documented 2

Practical Treatment Algorithm

Initial Treatment Phase

• Start griseofulvin at 10-20 mg/kg/day (for children 30-50 lbs: 125-250 mg daily; over 50 lbs: 250-500 mg daily) 3, 1
• Administer with fatty food to increase absorption and bioavailability 3, 4
• Continue for the full 2-4 week course even if lesions clear earlier 1

Monitoring and Endpoint Determination

• At 2-4 weeks: Perform repeat microscopy (KOH preparation) or culture to confirm mycological clearance 2, 1
• If mycology remains positive despite clinical improvement, continue current therapy for an additional 2-4 weeks 5
• Only discontinue treatment once both clinical AND mycological cure are achieved 2

Important Caveats

Treatment Failure Considerations

• If there is no clinical improvement after 2-4 weeks, consider that griseofulvin has variable efficacy depending on the causative organism (88.5% response for Microsporum vs. 67.9% for Trichophyton species) 3, 4
• In resistant cases, doses up to 25 mg/kg/day may be necessary for more prolonged periods 3, 4
• Alternative agents like itraconazole (87% cure rate) or terbinafine may be superior, particularly for Trichophyton infections 2

Prevention of Recurrence

• Screen and treat family members, as over 50% may be affected with anthropophilic species 2
• Clean all contaminated items (combs, brushes, towels) with disinfectant or 2% sodium hypochlorite solution 2
• Implement preventive measures including avoiding skin-to-skin contact and not sharing personal items 2