What is the recommended treatment for an adult patient with Tinea capitis (ringworm of the scalp)?

Treatment of Tinea Capitis in Adults

Oral terbinafine 250 mg daily for 2-4 weeks is the recommended first-line treatment for adults with tinea capitis, particularly when caused by Trichophyton species (the most common pathogen in North America). 1, 2

Treatment Algorithm

First-Line Therapy Selection

For Trichophyton species infections (most common in adults):

• Terbinafine 250 mg daily for 2-4 weeks is preferred due to superior efficacy against Trichophyton tonsurans, the predominant causative organism 1, 2
• Terbinafine is fungicidal and shows higher efficacy rates (94% effective treatment) compared to other agents 3

For Microsporum species infections (less common):

• Griseofulvin 500 mg daily (or 15-20 mg/kg/day) for 6-8 weeks is more effective, with an 88.5% response rate for Microsporum versus 67.9% for Trichophyton 1, 4

Second-Line Options

If terbinafine is ineffective or contraindicated:

• Itraconazole 100 mg daily for 2-4 weeks (86% effective treatment rate) 3
• Fluconazole 6 mg/kg/day for 2-3 weeks (84% effective treatment rate), though this is less cost-effective and has limited comparative data 5, 3

Critical Treatment Principles

Oral therapy is mandatory:

• Topical therapy alone is completely ineffective for tinea capitis and should never be used as monotherapy 1
• The infection involves the hair shaft, which cannot be adequately treated with topical agents alone 6

Treatment endpoint is mycological cure, not clinical improvement:

• Continue therapy until mycological clearance is documented, not just when symptoms resolve 5, 1
• If clinical improvement occurs but mycology remains positive, continue current therapy for an additional 2-4 weeks 1, 2

Diagnostic Confirmation

Before initiating treatment:

• Obtain scalp samples via scraping, hair pluck, brush, or swab for microscopy (potassium hydroxide preparation) and fungal culture 5, 1
• Treatment can be started empirically based on clinical presentation while awaiting culture results 1
• Trichoscopy (dermoscopic imaging of scalp and hair) is a useful adjunct to physical examination 6

Management of Treatment Failure

If no clinical improvement after initial therapy course:

• Switch to second-line therapy 2
• Consider factors contributing to failure: poor compliance, suboptimal drug absorption, organism resistance, or reinfection 1, 2
• For resistant cases, extend treatment duration 2

Prevention of Transmission and Recurrence

Screen and treat household contacts:

• Over 50% of family members may be affected with anthropophilic species like T. tonsurans 5
• All close contacts should be screened if T. tonsurans is identified 1

Environmental decontamination:

• Clean all contaminated personal items (hairbrushes, combs, towels) with disinfectant or 2% sodium hypochlorite solution 5, 2
• Avoid sharing personal items and skin-to-skin contact with infected individuals 5, 2

Common Pitfalls

Avoid griseofulvin as first-line for Trichophyton infections:

• Griseofulvin requires longer treatment duration (6-8 weeks versus 2-4 weeks), is less effective than terbinafine for Trichophyton species, and has higher rates of gastrointestinal adverse effects 5, 3

Do not use fluconazole as first-line:

• Fluconazole is less cost-effective than terbinafine and has limited comparative efficacy data 5

Monitor for emerging antifungal resistance:

• While rare in tinea capitis to date, dermatophyte resistance to antifungal agents is rising among superficial fungal infections generally 6

Special Considerations for Adults

• Postmenopausal women, particularly African American or Black women, are at highest risk 6
• Adults with immunosuppression, crowded living conditions, animal exposure, or households with affected children have increased infection risk 6
• The prognosis is excellent with prompt and adequate treatment, but delayed diagnosis or inadequate treatment can result in permanent scarring alopecia 6