Fungal infections of skin and nails
Dermatophytes, Candida and Malassezia; confirming the diagnosis before oral therapy, terbinafine and azole choices and interactions, PBS rules for onychomycosis, terbinafine-resistant Trichophyton indotineae, and how to take and send a skin biopsy for infection.
Tier 1Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Three groups cause most superficial fungal infection: dermatophytes (Trichophyton, Microsporum, Epidermophyton), Candida and Malassezia.
- Scrape before you treat anything you plan to treat orally or for weeks. Microscopy and culture are cheap, and many dystrophic nails and annular rashes aren't fungal.
- Limited skin disease: topical terbinafine or an azole. Hair, nails, extensive disease or failed topical treatment: oral terbinafine for dermatophytes, an azole for Candida and Malassezia.
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Sources
- Therapeutic Guidelines: Dermatology and Antibiotic (fungal skin and nail infections)AU/NZTherapeutic Guidelines Limited (eTG complete), current eTG edition, accessed November 2026 (topic version not verified)
- National Healthy Skin Guideline: for the diagnosis, treatment and prevention of skin infections for Aboriginal and Torres Strait Islander children and communities in Australia (2nd edition)AU/NZThe Kids Research Institute Australia and Australian Healthy Skin Consortium, 2nd edition, 2023
- PBS Schedule: terbinafine 250 mg tablet, items 2804N (onychomycosis) and 2285G (dermatophyte infection)AU/NZAustralian Government Department of Health, Disability and Ageing (PBS), Schedule checked November 2026
- Chua KYL et al. Optimising the detection of Trichophyton indotineae and its prevalence in a large Australian laboratory. Pathology 2025;57:762-6AU/NZPathology (RCPA), 2025
- Roudbary M et al. Emergence of Trichophyton indotineae: in vitro susceptibility data from a mycology reference laboratory in Australia. JAC Antimicrob Resist 2026;8:dlag159AU/NZJAC-Antimicrobial Resistance, 2026
- Ameen M et al. British Association of Dermatologists guideline for managing fungal nail infection (onychomycosis) 2026. Br J Dermatol 2026British Association of Dermatologists, 2026 (replaces the 2014 guideline)
- Evans EG, Sigurgeirsson B. Double blind, randomised study of continuous terbinafine compared with intermittent itraconazole in treatment of toenail onychomycosis (L.I.ON). BMJ 1999;318:1031-5BMJ, 1999
- Last updated
- 14 November 2026
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