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- Presentation
Five-Step Approach to Diagnosing and Treating Onychomycosis in the Era of Antifungal Resistance
Description
The speaker outlines a five-step approach to diagnosing and treating onychomycosis amid rising antifungal resistance. First, make a bedside clinical diagnosis using clues such as asymmetric toenail disease, tinea pedis, prior treatment response, dermatophytoma, and classic distal onycholysis with subungual hyperkeratosis, while remembering that abnormal fingernails may suggest psoriasis rather than fungus. Second, confirm the diagnosis in the lab with fungal culture or nail debris/plate examination, looking for hyphae and favoring dermatophytes over possible contaminant molds. Third, choose treatment based on disease severity and organism: oral terbinafine, itraconazole, or fluconazole, with terbinafine often used daily and longer courses commonly favored in practice; itraconazole may be daily or pulse-dosed; fluconazole is typically weekly. The speaker notes increasing terbinafine resistance and recommends itraconazole when terbinafine fails, but warns about itraconazole’s many drug interactions, absorption issues, and potential for congestive heart failure, including edema monitoring. Topical options such as ciclopirox, efinaconazole, and tavaborole are useful for mild disease, patients who cannot take oral therapy, and especially dermatophytoma. Fourth, reassess progress at follow-up and, if response is poor, reconsider the diagnosis, repeat cultures, and switch therapy if resistance is suspected. Fifth, prevent reinfection with patient education, foot antifungal maintenance, and hygiene measures such as wearing socks and avoiding barefoot exposure in public areas.
View moreConclusions
- Effective management of distal lateral subungual onychomycosis requires a stepwise approach of clinical diagnosis, laboratory confirmation, treatment selection, follow-up, and reinfection prevention.
- Clinical clues such as asymmetric toenail involvement, associated tinea pedis, prior antifungal response, and dermatophytoma can help distinguish true onychomycosis from other nail disorders.
- Laboratory confirmation should focus on proving fungal hyphae and identifying a dermatophyte pathogen, since non-dermatophyte molds may represent contamination.
- Terbinafine remains a main first-line oral treatment, but resistance is increasingly common and may require longer treatment courses or alternative therapy.
- Itraconazole is an important alternative for terbinafine failures, but its use is limited by major drug interactions, absorption issues, and potential congestive heart failure risk.
- Topical agents such as efinaconazole, tavaborole, and ciclopirox are useful for mild disease, patients who cannot take oral therapy, and especially dermatophytomas when applied under the nail.
- Patients should be reassessed during treatment to confirm nail improvement, because lack of response should prompt reconsideration of the diagnosis and repeat culture if needed.
- Preventing recurrence is essential because cured patients remain prone to reinfection and benefit from ongoing foot care, tinea pedis treatment, and avoidance of high-risk barefoot exposure.
- Ahmad SR, Singer SJ, Leissa BG. Congestive heart failure associated with itraconazole. Lancet. 2001. PMID: 11403818. DOI: 10.1016/S0140-6736(00)04891-1.#10.1016/S0140-6736(00)04891-1