T. indotineae is the newly-recognised dermatophyte species, associated with genotype VIII of the T. mentagrophytes / interdigitale complex, that has become endemic in India and is the dominant cause of recalcitrant inflammatory dermatophytosis. Its hallmark: high-level terbinafine resistance driven by specific point mutations in the squalene epoxidase (SQLE) gene. Increasing concern: emerging reduced susceptibility to azole antifungals via CYP51B gene duplication, raising the spectre of multidrug-resistant strains.
The clinical picture is characteristic and alarming: extensive, inflammatory tinea corporis / cruris / faciei lesions, often steroid-misuse-modified (Indian over-the-counter clobetasol creams are the dominant precipitating factor), failing repeated terbinafine 250 mg/day courses, recurring within weeks of apparent clearance. India-specific scale: case numbers have increased dramatically over the past decade. Other countries (UK, Ontario, Europe, USA) now report imported cases from India and growing concern about global spread.
Evidence-supported treatment protocol at DermaVue Kochi:
1. Diagnosis: KOH microscopy (positive but cannot identify species); fungal culture (Sabouraud's agar) for species identification; molecular ITS sequencing where available for definitive T. indotineae confirmation.
2. First-line in confirmed/suspected T. indotineae: itraconazole 200 mg/day for 1-12 weeks, extended to 12-24 weeks for chronic recalcitrant cases. Higher doses (200 mg BID = 400 mg/day) in widespread involvement.
3. Second-line for multi-azole-resistant cases: voriconazole (higher cost, narrow therapeutic window, LFT monitoring).
4. Adjuncts: topical antifungal (luliconazole, sertaconazole, eberconazole, preferred for lower resistance development than ketoconazole) + steroid discontinuation (NON-NEGOTIABLE) + occlusion control + family-contact screening.
DermaVue Kochi practice: culture + sensitivity for any chronic/recurrent case before prescription; structured 8-12 week itraconazole course with monthly LFT; explicit patient education on steroid-cream avoidance; household contact screening built into the protocol.