Onychomycosis

Test clinically suspected onychomycosis before committing a patient to prolonged treatment, particularly before an oral agent. Nail dystrophy from traumatic onycholysis, psoriasis, lichen planus, trachyonychia, and toe or foot deformity can resemble distal-lateral subungual disease; an incorrect diagnosis exposes patients to unnecessary systemic adverse effects and delays diagnosis of another nail disorder. Wolters Kluwer+1Wolters KluwerAccuracy of Dermoscopy as a Point-of-Care Tool... : Journal of the Philippine Dermatological SocietyPubMedOnychomycosis: Rapid Evidence Review - PubMed

Use direct KOH microscopy as a rapid first test when an immediate result will change the visit plan. If KOH is negative but clinical suspicion remains high, submit a nail clipping for PAS histology and/or fungal culture rather than treating the negative test as exclusionary; reported KOH sensitivity is variable, and PAS generally outperforms KOH and culture for detecting fungal elements. PubMed+1PubMedDiagnosing Onychomycosis: What’s New? - PMCPubMedOnychomycosis: Rapid Evidence Review - PubMed

Add fungal culture when organism identification will alter management, including suspected yeast or nondermatophyte mold infection, atypical morphology, prior treatment failure, or anticipated alternative systemic therapy. A positive PAS confirms fungal invasion but does not identify species; culture provides organism identification but has lower positivity and is slow. Wiley+2WileyS1 Guideline onychomycosis - Nenoff - 2023 - Wiley Online LibraryScienceDirectComparison of diagnostic methods in the evaluation of onychomycosis - ScienceDirectWolters KluwerMethods for Diagnosing Onychomycosis: A Comparative Study... : Dermatologica Sinica

Offer treatment when nail disease causes pain, functional limitation, distress, or creates clinically important risk, including a history of lower-extremity cellulitis or diabetes with additional cellulitis risks such as prior cellulitis, venous insufficiency, or edema. Treatment is not mandatory for every confirmed infection; align the regimen with nail burden, patient preference, interaction risk, and ability to adhere to a prolonged course. PubMed+1PubMedOnychomycosis: Rapid Evidence Review - PubMedPubMedIntroduction - Clinical Review Report: Efinaconazole (Jublia) - NCBI Bookshelf

Use an oral agent when disease is moderate to severe, involves multiple nails, or when the likelihood of topical penetration is poor. Expert guidance summarized in a clinical review reserves systemic agents for moderate involvement of 20% to 60% of the nail plate and severe involvement above 60%; topical therapy is an option for mild-to-moderate disease at 60% or less or when oral therapy is contraindicated. PubMedPubMedIntroduction - Clinical Review Report: Efinaconazole (Jublia) - NCBI Bookshelf

For confirmed dermatophyte disease requiring systemic treatment, prescribe terbinafine 250 mg orally once daily for 6 weeks for fingernail onychomycosis or 12 weeks for toenail onychomycosis. Terbinafine is FDA-indicated for dermatophyte onychomycosis and is generally preferred to topical therapy because it is more effective and has a shorter treatment duration. dailymed nlm nih+1dailymed nlm nihThese highlights do not include all the information needed to use TERBINAFINE TABLETS safely and effectively. See full prescribing information for TERBINAFINE TABLETS. TERBINAFINE tablets, for oral use Initial U.S. Approval: 1992PubMedOnychomycosis: Rapid Evidence Review - PubMed

Use topical therapy when infection is limited, systemic drug interactions or hepatic disease preclude terbinafine, or the patient prioritizes avoidance of systemic toxicity. Efinaconazole 10% solution and tavaborole 5% solution are FDA-approved for toenail onychomycosis; ciclopirox 8% lacquer is FDA-approved for fingernail and toenail disease. Topical treatment has negligible systemic interaction risk but requires longer treatment and has limited cure rates relative to oral therapy. PubMed+1PubMedCombination Therapy Should Be Reserved as Second-Line Treatment of Onychomycosis: A Systematic Review of Onychomycosis Clinical TrialsPubMedIntroduction - Clinical Review Report: Efinaconazole (Jublia) - NCBI Bookshelf

Before terbinafine, evaluate for chronic or active liver disease and review the medication list for CYP2D6-sensitive drugs. Terbinafine inhibits CYP2D6; clinically relevant interaction review is particularly important for tricyclic antidepressants, SSRIs, atypical antipsychotics, beta blockers, tamoxifen, and metoprolol. dailymed nlm nih+3dailymed nlm nihThese highlights do not include all the information needed to use TERBINAFINE TABLETS safely and effectively. See full prescribing information for TERBINAFINE TABLETS. TERBINAFINE tablets, for oral use Initial U.S. Approval: 1992PubMedOnychomycosis: Old and New - PMCPubMedOnychomycosis: Rapid Evidence Review - PubMedPubMedTerbinafine - StatPearls - NCBI Bookshelf

Counsel patients to report symptoms compatible with drug reaction, depressive symptoms, or clinically significant adverse effects. The FDA label reports headache, diarrhea, rash, dyspepsia, liver-enzyme abnormalities, pruritus, taste disturbance, nausea, abdominal pain, and flatulence among common adverse reactions; discontinue terbinafine if signs or symptoms of drug reaction occur. dailymed nlm nihdailymed nlm nihThese highlights do not include all the information needed to use TERBINAFINE TABLETS safely and effectively. See full prescribing information for TERBINAFINE TABLETS. TERBINAFINE tablets, for oral use Initial U.S. Approval: 1992

Set expectations before starting therapy: complete cure requires both mycologic clearance and a visually clear nail, and reported cure rates are limited even with oral therapy. Relapse has been reported as high as 25%, and recurrence estimates range from 6.5% to 53%; reassess persistent dystrophy with repeat mycologic testing rather than reflexively extending or repeating systemic therapy. PubMedPubMedOnychomycosis: Old and New - PMC

When a nail remains abnormal after an adequate course, first distinguish slow outgrowth from active infection. Because complete cure requires mycologic and clinical clearance and relapse or recurrence is common, obtain repeat KOH, PAS, and/or culture from a properly collected proximal subungual specimen before repeating systemic treatment. ScienceDirect+1ScienceDirectOnychomycosis: An evaluation of three sampling methods - ScienceDirectPubMedOnychomycosis: Old and New - PMC

A negative culture alone does not reliably exclude persistent infection because culture is less sensitive than PAS and is vulnerable to poor sampling. If repeated testing does not confirm fungus, redirect the workup toward mimics such as traumatic onycholysis, psoriasis, lichen planus, or trachyonychia rather than exposing the patient to serial antifungal courses. ScienceDirect+3ScienceDirectComparison of diagnostic methods in the evaluation of onychomycosis - ScienceDirectWolters KluwerAccuracy of Dermoscopy as a Point-of-Care Tool... : Journal of the Philippine Dermatological SocietyWolters KluwerComparative Evaluation of Potassium Hydroxide Mount, Fungal ... : Indian Journal of Dermatopathology and Diagnostic DermatologyWolters KluwerMethods for Diagnosing Onychomycosis: A Comparative Study... : Dermatologica Sinica

If culture identifies a nondermatophyte mold or yeast, or if disease is atypical or recalcitrant, use the identified organism to reassess drug selection. Itraconazole has broader reported activity against dermatophytes, yeasts, and nondermatophyte molds, whereas terbinafine is FDA-indicated specifically for dermatophyte onychomycosis. dailymed nlm nih+1dailymed nlm nihThese highlights do not include all the information needed to use TERBINAFINE TABLETS safely and effectively. See full prescribing information for TERBINAFINE TABLETS. TERBINAFINE tablets, for oral use Initial U.S. Approval: 1992PubMedOnychomycosis: Old and New - PMC