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- Presentation
State-of-the-Art Management of Onychomycosis in the Age of Antifungal Resistance
Description
The speaker reviews state-of-the-art management of onychomycosis in the era of antifungal resistance and emphasizes five main principles. First, diagnosis must be confirmed with laboratory testing rather than relying on appearance alone; nail clippings with PAS/GMS or KOH can confirm fungal elements, and culture helps identify the pathogen, with dermatophytes being the most likely cause. Second, clinicians must recognize that antifungal resistance is an increasing global problem, especially resistance to terbinafine due to squalene epoxidase gene mutations or enzyme overproduction. Third, standard treatment options include terbinafine, itraconazole, and fluconazole, but routine short courses may not eradicate infection completely. Fourth, treatment should be more aggressive and aimed at eradication, with the speaker recommending extended courses such as terbinafine for at least six months, itraconazole for six to eight months or longer, and fluconazole weekly until the nail grows out. Fifth, if infection persists or recurs, possible causes include resistance, non-dermatophyte molds, poor adherence, or another nail disorder; management may include higher-dose itraconazole, increased terbinafine dosing in select cases, susceptibility testing, topical efinaconazole, or combination therapy such as terbinafine plus fluconazole.
View moreConclusions
- Onychomycosis should not be diagnosed by appearance alone, because laboratory confirmation is essential in the era of antifungal resistance.
- Antifungal resistance, especially terbinafine resistance in dermatophytes, is a real and growing global problem.
- When terbinafine fails, resistance may be due to squalene epoxidase mutations or increased enzyme production, so the organism and mechanism need to be considered.
- Standard short-course treatment is often insufficient, and therapy should be extended and intensified to treat until the nail is cleared.
- Itraconazole becomes the preferred next option when terbinafine resistance or failure is suspected, often requiring higher or longer dosing than traditional regimens.
- Higher-dose terbinafine can still help in some resistant or hard-to-treat cases, particularly when standard dosing is inadequate.
- Fluconazole, efinaconazole, susceptibility testing, or combination oral therapy may be useful alternatives in selected nonresponsive cases.
- Overall management should shift from routine treatment to aggressive, goal-directed therapy that aims to eradicate infection completely.
- Drake et al. JAAD. 1997;37:740-45.
- Scher R. et al. JAAD. 1998;38:S77-86.
- Efficacy and Safety of Terbinafine 500 mg Once Daily in Patients with Dermatophytosis. Indian J Dermatol. 2017 Jul-Aug;62(4):395–399.#10.4103/ijd.ijd_191_17
- Terbinafine Resistance of Trichophyton Clinical Isolates Caused by Specific Point Mutations in the Squalene Epoxidase Gene. Antimicrobial Agents and Chemotherapy (American Society for Microbiology), 2017.#10.1128/aac.00115-17
- Siopi et al. Journal of Fungi, 2021.