EpistemisOnychomycosis
Specialty: Skin.
Why it occurs
- Superficial fungal infection due to dermatophyte fungi (*Trichophyton rubrum*, *Trichophyton mentagrophytes*)
- Yeast infection of the genus *Candida* (predominant in fingernails and associated with paronychia)
- Infection by non-dermatophytic molds (*Fusarium*, *Aspergillus*, *Scytalidium*)
- Biological predisposition (diabetes mellitus, peripheral arterial insufficiency)
- Repetitive nail microtrauma and continuous exposure to humid environments.
Initial workup
Subungual scraping of the most proximal debris for direct examination with 20% potassium hydroxide (KOH) (identification of septate hyphae or yeasts) and mycological culture in Sabouraud medium with and without cycloheximide (gold standard for species typing). Nail biopsy with PAS staining in refractory cases with negative repeat cultures.
red flags
Presence of severe onychomycosis in decompensated diabetic patients or with critical arterial ischemia of the extremities, associated with acute paronychia with ascending erythema, cellulitis of the extremity or suspicion of distal osteomyelitis.
Standard management
- Terbinafine — oral antifungal of choice, fungal squalene epoxidase inhibitor; dose of 250 mg daily orally for 12 weeks on toenails, monitoring transaminases at baseline and at 6 weeks
- Itraconazole — administered in pulse therapy of 400 mg/day for one week a month, for 3 months for toenails
- Ciclopirox in 8% nail polish — daily topical treatment for mild distal cases involving less than 50% of the nail and without matrix involvement
- Amorolfine in 5% nail lacquer (weekly topical application as an alternative for localized treatment).
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Skin
- Listed causes
- 5
- Treatment options
- 4