Deep dermatophytosis is a rare condition in which dermatophytes invade deep into the skin. Predisposing factors include chronic superficial dermatophytosis, immunosuppression or the use of topical steroids. Clinical, mycological, and histological examination are crucial for accurate diagnosis. Microscopy and culture or molecular diagnostic are useful tools when identifying the causative dermatophyte species. Species-directed systemic antimycotic treatment is golden standard and require careful consideration of potential drug-drug interactions and monitoring for both efficacy and side effects, as argued in this review.