What is the management and dosing of tinea (fungal) infections?

Management of Tinea Infections

First-Line Treatment by Site and Severity

For moderate to severe tinea corporis, terbinafine 250 mg daily for 2-4 weeks is the preferred first-line treatment, particularly when Trichophyton species are suspected. 1

Tinea Corporis (Body) - Moderate to Severe

• Terbinafine 250 mg daily for 2-4 weeks is the preferred first-line agent due to superior efficacy against Trichophyton tonsurans, shorter treatment duration, and favorable safety profile 1
• Itraconazole 100 mg daily for 15 days is the broad-spectrum alternative when the organism is unknown or mixed infection is possible, as it covers both Trichophyton and Microsporum species 1
• Alternative dosing for itraconazole: 5 mg/kg/day for 2-4 weeks 1

Tinea Corporis/Cruris - Mild to Moderate

• Topical antifungals applied once or twice daily for 2 weeks are the primary treatment for mild infections 2, 3
• Newer topical azoles (luliconazole, efinaconazole, sertaconazole) or allylamines require fewer applications and shorter duration 4
• Oral therapy alternatives if topical fails:
  • Fluconazole 50-100 mg daily for 2-3 weeks OR 150 mg once weekly for 2-3 weeks 5
  • Itraconazole 100 mg daily for 2 weeks OR 200 mg daily for 7 days 5
  • Terbinafine 250 mg daily for 1-2 weeks 5

Tinea Pedis (Feet)

• Topical antifungals applied once or twice daily for 4 weeks for mild to moderate infections 2, 3
• Allylamines require only 1-2 weeks of topical treatment compared to 4 weeks for azoles 2
• Oral therapy for chronic/dry type or extensive disease:
  • Terbinafine 250 mg daily for 2 weeks 5
  • Itraconazole 100 mg daily for 2 weeks OR 400 mg daily for 1 week 5
  • Fluconazole 150 mg once weekly (pulse dosing) 5
• Severe presentations (dermatophytosis complex) may require combined antifungal and antibacterial therapy 6

Tinea Capitis (Scalp)

• Griseofulvin 10 mg/kg daily for 4-6 weeks is the standard treatment 7
• Pediatric dosing: 30-50 lbs: 125-250 mg daily; >50 lbs: 250-500 mg daily in divided doses 7
• Adult dosing: 500 mg daily (can start at 750 mg-1 g daily for widespread lesions, then reduce to 500 mg after response) 7

Tinea Versicolor

• Topical antifungals are first-line to reduce spore transmission 8
• Itraconazole 50-100 mg daily for 2-4 weeks for extensive disease or topical-resistant cases 8
• Fluconazole 400 mg single dose is also effective 5
• Itraconazole 200 mg daily for 5-7 days is an alternative 5

Tinea Unguium (Onychomycosis)

• Oral therapy is primary treatment 3
• Griseofulvin: fingernails require at least 4 months; toenails require at least 6 months 7
• Topical amorolfine or ciclopirox formulations approved for milder cases 3

Critical Treatment Algorithm

1. Confirm diagnosis through KOH preparation or fungal culture before initiating therapy 1
2. Start treatment while awaiting mycology results if moderate to severe disease with classic clinical signs 1
3. If Trichophyton suspected/confirmed: Use terbinafine 250 mg daily for 2-4 weeks 1
4. If organism unknown or mixed infection possible: Use itraconazole 100 mg daily for 15 days 1
5. Continue treatment for at least 1 week after clinical clearing 2

Essential Management Principles

The definitive endpoint is mycological cure, not just clinical resolution. 1

• Repeat mycology sampling is essential until mycological clearance is documented 1
• Medication must be continued until the infecting organism is completely eradicated as indicated by appropriate clinical or laboratory examination 7
• Clinical relapse will occur if medication is not continued until the organism is eradicated 7

Infection Control Measures

• Screen and treat all family members - over 50% may be affected with anthropophilic species like T. tonsurans 1
• Clean all contaminated items with disinfectant or 2% sodium hypochlorite solution 1
• Avoid skin-to-skin contact with infected individuals and do not share personal items 1
• Clean contaminated combs and brushes properly 8
• General hygiene measures should be observed to control sources of infection or reinfection 7

Common Pitfalls to Avoid

• Never rely on topical therapy alone for moderate to severe disease - this results in treatment failure 1
• Never stop treatment based solely on clinical improvement without confirming mycological cure 1
• Never ignore family screening - this leads to reinfection 1
• Concomitant use of appropriate topical agents is usually required, particularly in tinea pedis 7
• In some forms of tinea pedis, yeasts and bacteria may be involved; griseofulvin will not eradicate these associated infections 7

Safety Profile

• Gastrointestinal symptoms are the most common adverse effects, occurring in <8% of patients 1
• Adverse effects requiring discontinuation are rare (0.8% with griseofulvin) 1
• Inflammation may necessitate use of an agent with inherent anti-inflammatory properties or combination antifungal/steroid agent, though the latter should be used with caution due to potential for atrophy 2

Follow-Up

• Follow-up should include both clinical and mycological assessment 8
• Relapse remains a problem, particularly with tinea pedis/unguium 3
• Appropriate follow-up duration and patient education on proper foot hygiene are important components of effective therapy 3