What is the treatment for tinea corporis (ringworm of the body)?

Treatment of Tinea Corporis (Ringworm of the Body)

For localized tinea corporis, topical antifungal therapy with terbinafine or an azole (such as clotrimazole) applied for 2-4 weeks is the first-line treatment, while extensive, resistant, or recurrent infections require oral antifungal therapy with itraconazole 100 mg daily for 15 days or terbinafine 250 mg daily for 1-2 weeks. 1, 2

Diagnostic Confirmation

• Accurate diagnosis should be confirmed through potassium hydroxide (KOH) preparation microscopy of skin scrapings from the active border of the lesion, which provides rapid preliminary diagnosis 1, 3
• Fungal culture on Sabouraud agar is the gold standard when diagnosis is uncertain, infection is widespread or resistant to treatment, or in immunocompromised patients 1, 4, 5
• Look for well-demarcated, sharply circumscribed, oval or circular, mildly erythematous, scaly patches or plaques with a raised leading edge and mild pruritus 5

First-Line Topical Therapy for Localized Infection

• Terbinafine 1% cream applied once or twice daily for 1-2 weeks is highly effective, with the advantage of shorter treatment duration and fewer applications 2, 3, 6
• Terbinafine demonstrated significantly higher clinical cure rates compared to placebo (RR 4.51, NNT 3) in pooled data 6
• Naftifine 1% cream applied once or twice daily for 2-4 weeks is another effective option, showing mycological cure rates of RR 2.38 (NNT 3) versus placebo 6
• Clotrimazole 1% cream applied twice daily for 2-4 weeks achieved mycological cure rates of RR 2.87 (NNT 2) compared to placebo 6
• Treatment should continue for at least one week after clinical clearing of infection to ensure mycological cure 3, 6

Oral Therapy Indications

• Oral antifungal therapy is indicated when the infection is extensive (multiple lesions or large body surface area), deep, recurrent, chronic, resistant to topical treatment, or the patient is immunocompromised 1, 5

Oral Antifungal Options

• Itraconazole 100 mg orally once daily for 15 days achieves 87% mycological cure rate, superior to griseofulvin's 57% cure rate 7, 1
• Terbinafine 250 mg orally once daily for 1-2 weeks is particularly effective against Trichophyton tonsurans infections 7, 1
• Griseofulvin 500 mg orally once daily for 2-4 weeks is an alternative but requires longer treatment duration and has lower efficacy 8, 9

Important Caveats and Pitfalls

• Avoid using topical corticosteroid-antifungal combination creams beyond short-term use - while they show higher clinical cure rates at end of treatment (RR 0.67 for azoles alone vs combination), they carry risks of skin atrophy and steroid-associated complications, and are not recommended in clinical guidelines 3, 6
• Do not rely on clinical appearance alone in patients who have used topical corticosteroids or calcineurin inhibitors, as these medications can mask typical features and make diagnosis difficult 5
• Ensure mycological cure, not just clinical improvement, as the definitive treatment endpoint - clinical clearing does not guarantee eradication of the organism 1, 3

Prevention and Management of Recurrence

• Avoid skin-to-skin contact with infected individuals, do not share towels or personal items, and cover lesions during treatment 7
• Clean contaminated combs, brushes, and fomites with disinfectant or 2% sodium hypochlorite solution 1
• Screen and treat family members and close contacts, especially for anthropophilic species like Trichophyton tonsurans where over 50% of household members may be affected 1
• Address exacerbating factors such as excessive skin moisture and maintain good personal hygiene 3, 4

Monitoring and Follow-Up

• Repeat mycology sampling at the end of the standard treatment period to document mycological clearance 1
• If clinical improvement occurs but mycology remains positive, continue current therapy for an additional 2-4 weeks 10
• If no clinical improvement occurs, consider poor compliance, suboptimal drug absorption, organism insensitivity, or reinfection as potential causes 10
• Monitor for adverse effects, which are generally mild (irritation, burning, gastrointestinal disturbances, or rashes occurring in less than 8% of patients with oral terbinafine) 10, 6