What is the recommended management for ringworm (tinea) infections?

Management of Ringworm (Tinea) Infections

For localized tinea corporis and tinea cruris, topical antifungal therapy is first-line treatment, but oral antifungals are indicated when infections are extensive, resistant to topical treatment, involve hair follicles (tinea capitis), or occur in immunocompromised patients. 1, 2

Topical Therapy for Localized Disease

First-Line Topical Agents

• Terbinafine cream is highly effective for tinea corporis and tinea cruris, achieving clinical cure rates 4.5 times higher than placebo (NNT = 3). 3
• Naftifine 1% cream demonstrates strong efficacy, with mycological cure rates 2.4 times higher than placebo (NNT = 3) and clinical cure rates 2.4 times higher (NNT = 3). 3
• Clotrimazole 1% is an effective alternative, achieving mycological cure rates 2.9 times higher than placebo (NNT = 2). 3
• Treatment duration is typically 2-4 weeks for tinea corporis and tinea cruris. 4, 3

Important Considerations for Topical Therapy

• Avoid combination antifungal-corticosteroid products as part of antifungal stewardship to prevent resistance and optimize outcomes. 2
• Topical agents are ineffective for tinea capitis because they cannot penetrate hair follicles adequately. 2
• Concomitant topical therapy is usually required alongside oral treatment for tinea pedis. 4

Oral Antifungal Therapy

Indications for Oral Treatment

• Extensive disease not responding to topical agents 1, 2
• Tinea capitis (always requires oral therapy) 1, 2
• Immunocompromised patients 2
• Hair follicle involvement 2
• Treatment failure with topical agents 1

Oral Treatment Regimens

For Tinea Corporis/Cruris:

• Terbinafine 250 mg daily for 1-2 weeks is highly effective, particularly against Trichophyton tonsurans. 1, 5
• Itraconazole 100 mg daily for 15 days achieves 87% mycological cure rate. 1
• Fluconazole 50-100 mg daily for 2-3 weeks or 150 mg once weekly for 2-3 weeks is an alternative. 5

For Tinea Capitis:

• Terbinafine 250 mg daily for 1-2 weeks is first-line therapy due to superior efficacy, tolerability, and cost-effectiveness, especially for T. tonsurans infections. 1, 2
• Itraconazole 100 mg daily for 15 days is an alternative with 87% cure rate, superior to griseofulvin (57% cure rate). 1
• Griseofulvin should not be used as first-line treatment due to longer treatment duration, lower efficacy than terbinafine, and inferior cure rates. 1

For Tinea Pedis:

• Terbinafine 250 mg daily for 2 weeks is recommended. 5
• Itraconazole 100 mg daily for 2 weeks or 400 mg daily for 1 week is effective. 5
• Fluconazole 150 mg once weekly (pulse dosing) can be used. 5

For Tinea Unguium (Onychomycosis):

• Terbinafine is first-line therapy for nail infections. 2
• Treatment duration: fingernails require at least 4 months; toenails require at least 6 months. 4

Drug-Specific Considerations

Terbinafine:

• Most cost-effective option 2
• Superior efficacy against Trichophyton species 1
• Well-tolerated with minimal adverse effects 2

Itraconazole:

• Licensed for children over 12 years in the UK (used off-label in younger children elsewhere) 1
• Important drug interactions: enhanced toxicity with warfarin, certain antihistamines, antipsychotics, midazolam, digoxin, and simvastatin 1
• Not effective for pityriasis versicolor 5

Fluconazole:

• Third-line option with significant limitations 1
• Not licensed for tinea in children under 10 years in the UK 1
• Less cost-effective than terbinafine 1

Griseofulvin (if other agents unavailable):

• Adults: 500 mg daily (can increase to 750 mg-1 g daily for severe infections) 4
• Pediatric patients >2 years: 10 mg/kg daily 4
• Requires longer treatment duration than alternatives 1

Diagnostic Confirmation

Accurate diagnosis is essential before initiating treatment, ideally confirmed through potassium hydroxide (KOH) preparation microscopy or fungal culture to identify the causative organism. 1, 4

Specimen Collection Methods

• Scalpel scraping for skin lesions 1
• Hair pluck for scalp involvement 1
• Brush or swab techniques as appropriate 1

Common Diagnostic Pitfalls

• Clinical diagnosis alone is unreliable—tinea corporis can mimic eczema, and onychomycosis can resemble dystrophic toenails from trauma or psoriasis. 2
• Fungal cultures may be negative despite active infection; repeat specimens increase diagnostic yield. 1

Treatment Monitoring and Follow-Up

The definitive endpoint for treatment should be mycological cure, not just clinical response. 1

• Repeat mycology sampling is recommended until mycological clearance is documented. 1
• Follow-up should include both clinical and mycological assessment. 1
• Treatment failure may require extending treatment duration or switching agents. 1
• Continue medication until the infecting organism is completely eradicated; clinical relapse occurs if treatment is stopped prematurely. 4

Prevention and Management of Recurrence

Screen and treat all family members when infection is caused by anthropophilic species (such as T. tonsurans), as over 50% of family members may be affected. 1

Specific Prevention Measures

• Avoid skin-to-skin contact with infected individuals 1
• Do not share towels, clothing, or personal items 1
• Cover lesions during treatment 1
• Clean contaminated combs, brushes, and fomites with disinfectant or 2% sodium hypochlorite solution 1
• Implement general hygiene measures to control sources of infection or reinfection 4

Emerging Resistant Tinea Infections

Emerging tinea infections may be more severe than classic infections and generally do not improve with first-line topical or oral antifungals. 2

• These infections may require prolonged oral antifungal therapy 2
• Specialized diagnostic testing may be necessary 2
• Emphasize antifungal stewardship to optimize outcomes and prevent resistance 2

Special Populations

Pediatric Considerations:

• Tinea corporis and tinea capitis are most common in prepubertal children 2
• Dosing for children >2 years: 10 mg/kg daily for griseofulvin 4
• Terbinafine and itraconazole dosing should be weight-based 1

Adolescents and Adults:

• Tinea cruris, tinea pedis, and tinea unguium are more common in this age group 2
• Standard adult dosing applies for oral antifungals 5