What is the treatment for a fungal infection on the scalp?

Treatment of Scalp Fungal Infection (Tinea Capitis)

Oral antifungal therapy is required for treating scalp fungal infections—topical therapy alone is not recommended. 1

Diagnostic Confirmation

Before initiating treatment, obtain specimens for laboratory confirmation:

• Collect scalp samples using scalpel scraping, hair plucking, brush sampling, or swabs 1
• Send for microscopy and culture on Sabouraud agar to identify the specific dermatophyte species 1
• Wood's lamp examination can identify Microsporum canis infections, which fluoresce under ultraviolet light 1
• Dermoscopy may reveal "comma-shaped" hairs in ectothrix infections or "corkscrew" hairs in Afro-Caribbean patients 1

When to Start Treatment

Begin treatment immediately if you observe:

• A kerion (painful, boggy, inflammatory scalp mass with pustules) 1
• Strong clinical suspicion with typical features: scaling, regional lymphadenopathy, or alopecia 1
• High-risk populations where waiting 2-4 weeks for culture results would increase transmission 1

Otherwise, wait for microscopy or culture confirmation before starting therapy 1

First-Line Oral Therapy

Griseofulvin (Licensed Treatment)

Griseofulvin remains the only licensed medication for tinea capitis in children in many countries 1, 2:

• Dosing: 20-25 mg/kg/day in single or divided doses 1, 3
• Duration: 6-8 weeks for most infections 1, 3, 2
• Administration: Take with fatty food to improve absorption 1
• Indications: Effective against Trichophyton and Microsporum species causing tinea capitis 2

Terbinafine (Alternative)

Consider terbinafine if griseofulvin is unavailable or ineffective 3:

• Duration: Weight-based dosing for 4 weeks 3
• Note: Unlicensed for children in some countries but widely used 1

Adjunctive Topical Therapy

Topical antifungal shampoos reduce spore transmission but cannot cure the infection alone 1:

• Ketoconazole 2% shampoo 1
• Selenium sulfide 1% shampoo 1
• Povidone-iodine shampoo 1

Use these to prevent spread to household contacts and reduce environmental contamination 1

Treatment Duration and Monitoring

Continue treatment until mycological clearance is documented, not just clinical improvement 3:

• Repeat fungal culture at the end of the standard treatment period 3
• Extend therapy if cultures remain positive or if treating resistant organisms like Trichophyton verrucosum (may require up to 3 weeks of incubation for culture) 1
• Increase griseofulvin dose to 25 mg/kg/day for resistant cases 1

Special Clinical Scenarios

Kerion Presentation

For severe inflammatory kerion:

• Start oral antifungals immediately without waiting for culture 1
• Consider oral corticosteroids if inflammation is severe (though not explicitly detailed in guidelines, this is common practice)
• Rule out secondary bacterial infection, which can complicate kerion 1

Treatment Failure

If initial therapy fails 1:

• Verify compliance and adequate dosing
• Confirm the organism through repeat culture
• Switch agents or prolong treatment duration based on culture results
• Consider alternative oral antifungals such as itraconazole or fluconazole (though less commonly used) 4, 5

Infection Control Measures

Prevent transmission and reinfection 3:

• Screen household contacts for asymptomatic carriage, especially with anthropophilic species like T. tonsurans 3
• Disinfect fomites: combs, brushes, hats, and pillowcases 3
• Provide antifungal shampoo to household contacts 3
• Avoid sharing personal items 3

Common Pitfalls

• Do not use topical therapy alone—it will fail to eradicate the infection from hair follicles 1
• Do not stop treatment when symptoms improve; continue until mycological cure is confirmed 3
• Do not confuse with dandruff or seborrheic dermatitis, which can present with similar diffuse scaling 6
• Do not misdiagnose kerion as bacterial abscess, though secondary bacterial infection should be considered 1
• Antifungal susceptibility testing is not routinely indicated, as resistance is rare 1