A 28-year-old woman presents with a 6-week history of pruritic erythematous patches on the medial thighs and inguinal folds, sparing the scrotum. KOH mount confirms dermatophyte infection. What is the drug of choice for tinea cruris?

Explanation

## Drug of Choice for Tinea Cruris **Key Point:** For uncomplicated tinea cruris, **topical antifungals are the first-line (drug of choice)** treatment. Miconazole 2% cream applied twice daily for 2–3 weeks is the standard recommendation for localized disease. ### Rationale for Topical Miconazole **High-Yield:** Tinea cruris is a superficial dermatophyte infection confined to the stratum corneum of the groin and medial thighs. Because the infection is superficial, topical therapy achieves adequate drug concentrations at the site of infection with minimal systemic exposure. - **Miconazole 2% cream** (or clotrimazole 1% cream) applied BD for 2–3 weeks is the standard first-line treatment per IADVL and international guidelines. - Topical allylamines (terbinafine 1% cream) are equally effective and may require a shorter course (1–2 weeks). - Cure rates with topical azoles exceed 85–90% for uncomplicated tinea cruris. ### Comparison of Antifungals for Tinea Cruris | Agent | Route | Dose | Duration | Notes | |-------|-------|------|----------|-------| | **Miconazole 2%** | Topical | BD | 2–3 weeks | **First-line for uncomplicated disease** | | Terbinafine 1% cream | Topical | OD/BD | 1–2 weeks | Equally effective topical option | | Terbinafine 250 mg | Oral | OD | 2–4 weeks | Reserved for extensive/refractory disease | | Fluconazole 150 mg | Oral | Weekly | 4–6 weeks | Alternative systemic option | | Griseofulvin 500 mg | Oral | BD | 6–12 weeks | Fungistatic; largely obsolete | ### When to Escalate to Systemic Therapy Oral antifungals (e.g., terbinafine 250 mg OD) are reserved for: 1. Failure of topical therapy after 3–4 weeks 2. Extensive lesions (>10 cm²) or widespread involvement 3. Significant maceration or secondary infection 4. Immunocompromised patients 5. Recurrent or chronic disease **Clinical Pearl:** The stem describes a 6-week history of tinea cruris with KOH confirmation but does **not** mention failure of prior topical therapy, extensive lesions, or immunosuppression. In the absence of these indications, topical miconazole 2% cream BD for 2–3 weeks remains the drug of choice. This is consistent with KD Tripathi (*Essentials of Medical Pharmacology*, 8th ed.) and IADVL guidelines, which recommend topical azoles as first-line for uncomplicated tinea cruris. **Reference:** KD Tripathi, *Essentials of Medical Pharmacology*, 8th ed.; IADVL Textbook of Dermatology, 4th ed.