What are the preferred systemic oral antifungal medications for treating tinea capitis?

Preferred Medications for Tinea Capitis

The preferred first-line medication for tinea capitis depends on the causative organism: terbinafine for Trichophyton species (2-4 weeks) and griseofulvin for Microsporum species (6-8 weeks), with oral antifungal therapy being mandatory as topical therapy alone is ineffective. 1, 2, 3

Treatment Selection Algorithm

Step 1: Obtain Mycological Diagnosis

• Collect scalp specimens via scalpel scraping, hair pluck, brush, or swab for microscopy and culture before initiating therapy 1, 2
• However, if a kerion is present or cardinal clinical signs are evident (scale, lymphadenopathy, alopecia), initiate treatment immediately while awaiting confirmatory mycology 1, 2, 3

Step 2: Species-Directed First-Line Therapy

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

Terbinafine is the preferred agent due to superior efficacy and shorter treatment duration 1, 2, 3

• Dosing by weight: 1, 2

  • <20 kg: 62.5 mg daily for 2-4 weeks
  • 20-40 kg: 125 mg daily for 2-4 weeks

  • 40 kg: 250 mg daily for 2-4 weeks

• Advantages: Shorter treatment course improves compliance; gastrointestinal disturbances and rashes occur in <8% of children 2, 3

• Critical caveat: Terbinafine fails against Microsporum species because it cannot be incorporated into hair shafts in prepubertal children and doesn't reach the scalp surface where arthroconidia are located 3

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

Griseofulvin is the preferred agent with 88.5% response rate for Microsporum infections 1, 2, 3

• Dosing by weight: 1, 2

  • <50 kg: 15-20 mg/kg/day (single or divided dose) for 6-8 weeks

  • 50 kg: 1 g/day (single or divided dose) for 6-8 weeks

• Licensing note: Griseofulvin remains the only licensed treatment for tinea capitis in children in the UK, though the suspension formulation is no longer licensed 1, 2

• Evidence superiority: Eight weeks of griseofulvin is significantly more effective than 4 weeks of terbinafine for confirmed Microsporum infection 3

• Disadvantage: Longer treatment duration (6-8 weeks) may reduce compliance 1, 2

Step 3: Managing Treatment Failure

If treatment fails, systematically evaluate: 1, 2, 3

• Lack of compliance
• Suboptimal drug absorption
• Organism insensitivity
• Reinfection from untreated contacts

Response-based approach: 1, 2

• Clinical improvement but positive mycology: Continue current therapy for additional 2-4 weeks
• No clinical improvement: Switch to second-line therapy immediately

Step 4: Second-Line Therapy

Itraconazole is the preferred second-line agent with activity against both Trichophyton and Microsporum species 1, 2, 3

• Dosing: 5 mg/kg/day for 2-4 weeks, or 50-100 mg/day for 4 weeks 1, 2
• Alternative strategy: If itraconazole was used first-line, switch to terbinafine for Trichophyton infections or griseofulvin for Microsporum species 1

Fluconazole can be considered for refractory cases, though its use has been relatively limited due to side effects and lack of cost advantage 1, 4

Critical Management Principles

Mycological Cure is the Endpoint

• Treatment success is defined by mycological clearance, not just clinical improvement 1, 2, 3
• Repeat mycology sampling is mandatory until clearance is documented 1, 2, 3

Topical Therapy Role

• Topical antifungals alone are not recommended and should never be used as monotherapy 1, 2, 3
• Topical therapy may be used as adjunctive treatment only 3
• Sporicidal shampoos (2% ketoconazole or 1% selenium sulfide) can aid in removing scales and reducing spore transmission 5

Contact Screening and Prevention

• Screen all family members and close contacts for T. tonsurans cases and treat positive cases 1, 2, 3
• Over 50% of household contacts may be affected with anthropophilic species 4
• Clean contaminated combs and brushes with disinfectant or 2% sodium hypochlorite solution 2, 3, 4

School Attendance

• Children receiving appropriate systemic therapy can attend school or nursery 1, 2, 3
• Exclusion is impractical and unnecessary once treatment is initiated 3

Special Clinical Scenarios

Kerion Management

• Initiate oral antifungal therapy immediately without awaiting culture results 3
• Consider adding topical or oral corticosteroids to alleviate severe inflammatory symptoms 3, 5
• Recognize that kerion is a fungal-driven inflammatory response, not a bacterial abscess 3

Asymptomatic Carriers

• In asymptomatic carriers with high spore load (no clinical infection but culture positive), systemic treatment is generally justified 1

Common Pitfalls to Avoid

• Never use terbinafine for Microsporum infections due to poor efficacy (67.9% response rate vs. 88.5% for griseofulvin) 2, 3
• Avoid underdosing griseofulvin: Higher doses (15-20 mg/kg/day) are needed due to increasing treatment failures with lower doses 3, 5
• Do not stop treatment based on clinical appearance alone: Continue until mycological cure is documented 1, 2, 3
• Do not overlook household contacts: Failure to screen and treat contacts leads to reinfection 1, 2, 4