What is the recommended treatment for tinea capitis in adults?

Treatment of Tinea Capitis in Adults

Recommended First-Line Therapy

Oral antifungal therapy is mandatory for tinea capitis in adults, with treatment selection based on the causative organism: terbinafine for Trichophyton species and griseofulvin for Microsporum species. 1

Topical therapy alone is not effective and should never be used as monotherapy for tinea capitis. 1, 2

Treatment Algorithm Based on Causative Organism

For Trichophyton Species (T. tonsurans, T. violaceum, T. soudanense)

Terbinafine is the preferred agent:

• Dosing: 250 mg orally once daily for 2-4 weeks for adults >40 kg 1, 2
• Efficacy: Superior to griseofulvin for Trichophyton infections, with shorter treatment duration improving compliance 1, 2
• Cure rates: 94% effective treatment rate at 12 weeks 3

For Microsporum Species (M. canis, M. audouinii)

Griseofulvin is the preferred agent:

• Dosing: 1 g orally daily (single or divided dose) for 6-8 weeks for adults >50 kg 1, 2
• Efficacy: 88.5% response rate for Microsporum versus only 67.9% for Trichophyton 1
• Rationale: Terbinafine is relatively ineffective against Microsporum because it cannot be incorporated into hair shafts effectively and does not reach scalp surface arthroconidia 1

Important caveat: Griseofulvin has significant contraindications including lupus erythematosus, porphyria, and severe liver disease 1, 2

When Organism is Unknown

If treatment must be initiated before culture results (presence of kerion, severe symptoms, or cardinal signs of scale, lymphadenopathy, alopecia):

• Consider local epidemiology: In North America, T. tonsurans accounts for the majority of cases, making terbinafine a reasonable empiric choice 4, 5
• Adjust therapy once culture results available 1

Second-Line Options

Itraconazole

• Dosing: 100 mg orally once daily for 15 days 1
• Efficacy: 87% mycological cure rate versus 57% for griseofulvin in comparative studies 1
• Cautions: Multiple drug interactions including enhanced toxicity with warfarin, certain antihistamines, antipsychotics, midazolam, digoxin, and simvastatin 6
• Licensing: Licensed for children >12 years in UK, but no specific adult restrictions 6

Fluconazole

• Dosing: 6 mg/kg/day for 2-3 weeks 3
• Efficacy: 84% effective treatment rate, comparable to other agents 3
• Limitations: Less cost-effective than terbinafine with limited comparative efficacy data 6

Management of Treatment Failure

Initial assessment should evaluate:

• Compliance: Verify patient adherence to prescribed regimen 1, 2
• Drug absorption: Consider taking griseofulvin with fatty foods to optimize absorption 1
• Organism sensitivity: Confirm causative species and ensure appropriate drug selection 1, 2
• Reinfection: Screen household contacts and address environmental sources 1, 2

If clinical improvement but persistent positive mycology:

• Continue current therapy for additional 2-4 weeks 2

If no clinical improvement:

• Switch to alternative agent based on organism (terbinafine to griseofulvin or vice versa) 2
• Consider higher doses: griseofulvin up to 25 mg/kg daily for more prolonged periods 7
• Consider itraconazole as third-line option 2

Essential Adjunctive Measures

Prevent reinfection and transmission:

• Screen and treat household contacts: Over 50% of family members may be affected with anthropophilic species like T. tonsurans 6, 2
• Decontaminate fomites: Clean all hairbrushes, combs, and towels with disinfectant or 2% sodium hypochlorite solution 6, 2
• Avoid sharing personal items: Towels, hats, combs, and other hair accessories 1, 6
• Cover lesions: Minimize skin-to-skin contact with others 1, 7

Adjunctive topical therapy:

• Sporicidal shampoos (selenium sulfide or 2% ketoconazole) can aid in removing scales and eradicating viable spores, though not curative alone 4, 5

Monitoring and Follow-Up

Mycological cure, not just clinical response, is the definitive treatment endpoint:

• Follow-up mycology sampling: Continue until mycological clearance documented 6, 7
• Assessment timing: Evaluate at weeks 4,8, and 12 from treatment initiation 3
• Liver monitoring: Generally unnecessary if therapy limited to ≤4 weeks 4

Special Considerations for Adults

Risk factors for tinea capitis in adults:

• Postmenopausal women, particularly African American or Black women 8
• Immunosuppression 8
• Crowded living conditions or close proximity to animals 8
• Household contact with affected children 8

Prognosis:

• Excellent with prompt and adequate treatment 8
• Critical pitfall: Delayed diagnosis or inadequate treatment can result in permanent scarring alopecia 8, 9
• Kerion requires immediate treatment: Failure to treat promptly leads to scarring and permanent hair loss 9

Emerging Concern: Antifungal Resistance

While tinea capitis infections resistant to antifungal therapy remain rare, resistance is rising among superficial fungal infections generally, necessitating antifungal stewardship 8