Management of Tinea Corporis
For localized tinea corporis, topical terbinafine 1% cream applied once daily for 1-2 weeks is the first-line treatment, while moderate to severe or extensive disease requires oral terbinafine 250 mg daily for 2-4 weeks. 1, 2
Diagnostic Confirmation
- Obtain skin scrapings for KOH preparation or fungal culture before initiating therapy to confirm dermatophyte infection 1, 2
- For moderate to severe disease with classic clinical signs (annular scaling plaques with central clearing), start treatment while awaiting mycology results 1
- Direct microscopic examination with potassium hydroxide or culture on appropriate medium is essential for accurate organism identification 3, 4
Treatment Algorithm by Disease Severity
Localized Disease (First-Line)
- Topical terbinafine 1% cream once daily for 1-2 weeks achieves 84-94% mycological cure rates and is superior to placebo 2, 5
- Alternative topical options include clotrimazole applied twice daily for 2-4 weeks 2, 6
- Continue treatment for at least one week after clinical resolution to ensure mycological clearance 2, 6
Moderate to Severe Disease (Oral Therapy Required)
When Trichophyton species are suspected or confirmed:
- Terbinafine 250 mg daily for 2-4 weeks is the preferred first-line treatment due to superior efficacy, shorter treatment duration, and favorable safety profile 1, 2
- Terbinafine has superior efficacy against Trichophyton tonsurans specifically 1
When organism is unknown or mixed infection possible:
- Itraconazole 100 mg daily for 15 days provides broad-spectrum coverage against both Trichophyton and Microsporum species 1, 7
- Alternative dosing: 5 mg/kg/day for 2-4 weeks 1
When Microsporum species are confirmed:
- Griseofulvin 500 mg daily (or 10 mg/kg/day in children) for 2-4 weeks is more effective than terbinafine for Microsporum infections 2, 3
- Griseofulvin dosing for adults: 0.5 g daily (125 mg four times daily, 250 mg twice daily, or 500 mg once daily) 3
- Pediatric dosing (>2 years): 10 mg/kg daily (30-50 lbs: 125-250 mg daily; >50 lbs: 250-500 mg daily) 3
Critical Management Principles
Treatment endpoint is mycological cure, not clinical resolution:
- Repeat mycology sampling is essential until mycological clearance is documented 1, 2
- Clinical improvement without mycological cure leads to relapse 1
- Continue medication until the infecting organism is completely eradicated as indicated by appropriate clinical or laboratory examination 3
Family screening and transmission control:
- Screen and treat all family members, as over 50% may be affected with anthropophilic species like T. tonsurans 1, 2
- Clean all contaminated items (brushes, combs, towels) with disinfectant or 2% sodium hypochlorite solution 1, 2
- Avoid skin-to-skin contact with infected individuals and do not share personal items 1, 2
Common Pitfalls to Avoid
- Do not rely on topical therapy alone for moderate to severe disease - this results in treatment failure 1
- Do not stop treatment based solely on clinical improvement - mycological cure must be confirmed 1, 2
- Do not ignore family screening - this leads to reinfection 1, 2
- Do not use terbinafine for Microsporum infections - it is relatively ineffective because it is not excreted in sweat or sebum of prepubertal children and cannot be effectively incorporated into the hair shaft 2
Safety and Adverse Effects
- 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
- Griseofulvin contraindications include lupus erythematosus, porphyria, and severe liver disease 2
- Itraconazole has significant drug interactions with warfarin, certain antihistamines, antipsychotics, midazolam, digoxin, cisapride, cyclosporine, and simvastatin 2