Treatment of Ringworm (Tinea Infections)
For localized tinea corporis (body) or tinea cruris (groin), apply topical terbinafine or naftifine twice daily for 1-2 weeks; for tinea capitis (scalp) or extensive disease, oral terbinafine is first-line therapy.
Topical Treatment for Localized Disease
For uncomplicated tinea corporis and tinea cruris affecting limited body surface area, topical antifungals are the treatment of choice 1, 2.
First-Line Topical Agents
Terbinafine 1% cream: Apply twice daily (morning and night) for 1 week for ringworm of the body or groin 3, 1. This allylamine demonstrates significantly higher clinical cure rates compared to placebo (RR 4.51, NNT 3) 2.
Naftifine 1% cream: Apply once or twice daily for 1-2 weeks 2. Shows superior mycological cure rates versus placebo (RR 2.38, NNT 3) with low-quality evidence supporting its efficacy 2.
Alternative Topical Agents
Azole antifungals (clotrimazole, miconazole, ketoconazole): Apply twice daily for 2-4 weeks for tinea corporis 4, 5. Clotrimazole demonstrates mycological cure rates superior to placebo (RR 2.87, NNT 2) 2.
Azoles and allylamines show no significant difference in mycological cure rates when compared head-to-head (RR 1.01) 2.
Treatment Duration by Site
- Tinea corporis: 2-4 weeks of topical therapy 4, 5
- Tinea cruris: 2 weeks of topical therapy 5
- Tinea pedis (athlete's foot): 4 weeks with azoles or 1-2 weeks with allylamines 5
Oral Treatment for Extensive or Refractory Disease
Systemic antifungal therapy is indicated for patients with extensive disease, lack of response to topical treatment, immunocompromise, or hair follicle involvement 1.
Oral Terbinafine (First-Line)
Oral terbinafine is considered first-line therapy for tinea capitis and extensive tinea infections because it is well tolerated, effective, and inexpensive 1.
- Adults: 250 mg daily 1
- Pediatric patients (>2 years): Dosing based on weight, typically 10 mg/kg daily 4
- Duration: 4-6 weeks for tinea capitis; 2-4 weeks for tinea corporis 4
Oral Griseofulvin (Alternative)
- Adults: 500 mg daily (can be given as 125 mg four times daily, 250 mg twice daily, or 500 mg once daily) 4
- Pediatric patients (>2 years): 10 mg/kg daily is usually adequate 4, 6
- 30-50 lbs: 125-250 mg daily
- Over 50 lbs: 250-500 mg daily
- Duration by site 4:
- Tinea capitis: 4-6 weeks
- Tinea corporis: 2-4 weeks
- Tinea pedis: 4-8 weeks
Site-Specific Considerations
Tinea Capitis (Scalp Ringworm)
- Always requires oral antifungal therapy because topical agents cannot adequately penetrate hair follicles 1, 6
- Oral terbinafine is first-line 1
- Oral griseofulvin is an effective alternative, particularly for Microsporum species 6
- Treatment duration: minimum 4-6 weeks 4, 6
- A 6-week course of griseofulvin effectively cleared tinea capitis with kerion formation in a documented pediatric case 6
Tinea Pedis (Athlete's Foot)
- Between the toes: Apply topical antifungal twice daily for 1 week 3
- Bottom or sides of foot: Apply topical antifungal twice daily for 2 weeks 3
- General treatment duration: 4 weeks with azoles or 1-2 weeks with allylamines 5
- Concomitant topical therapy is usually required along with hygiene measures 4
Critical Treatment Principles
Confirmation of Diagnosis
Accurate diagnosis of the infecting organism is essential before initiating treatment 4. Clinical diagnosis without testing may be unreliable because conditions like eczema can mimic tinea corporis 1.
- Identification should be made by direct microscopic examination with potassium hydroxide preparation or by culture 4, 5
- Culture or histologic examination is rarely required but may be necessary in resistant cases 5
Duration and Monitoring
- Medication must be continued until the infecting organism is completely eradicated as indicated by clinical or laboratory examination 4
- Treatment should continue for at least one week after clinical clearing of infection 5
- Clinical relapse will occur if medication is discontinued prematurely 4
Adjunctive Measures
- General hygiene measures should be observed to control sources of infection or reinfection 4
- For tinea pedis: wear well-fitting, ventilated shoes and change shoes and socks at least once daily 3
- Wash affected skin with soap and water and dry completely before applying topical agents 3
Important Caveats
Avoid Combination Steroid-Antifungal Products
Although combination antifungal-steroid creams show higher clinical cure rates at end of treatment (RR 0.67 for azoles alone vs. combination), they have similar mycological cure rates and carry risks of skin atrophy and other steroid-associated complications 2, 5. Antifungal stewardship emphasizes avoiding combination antifungal-corticosteroids to optimize outcomes and help prevent resistance 1.
Emerging Resistant Infections
Emerging tinea infections may be more severe than classic tinea infections and generally do not improve with first-line topical or oral antifungals 1. These infections may require prolonged oral antifungal therapy and specialized diagnostic testing 1.