Onychomycosis
Basics
Basics
Basics
Description
Description
Description
- Fungal infection of fingernails/toenails
- Caused mostly by dermatophytes but also yeasts and nondermatophyte molds
- Toenails are more commonly affected than fingernails.
- Synonym: tinea unguium
Epidemiology
Epidemiology
Epidemiology
Prevalence
- Occurs in 2–10% of general population
- Predominant age: 20% in adults >60 years of age, 50% in adults >70 years of age (1)
- Rare before puberty
- Prevalence 15–40% in persons with human immunodeficiency infection
- Estimated 50% of all nail disorders in the outpatient setting (1)
Etiology and Pathophysiology
Etiology and Pathophysiology
Etiology and Pathophysiology
- Dermatophytes: Trichophyton (Trichophyton rubrum most common), Epidermophyton, Microsporum
- Yeasts: Candida albicans (most common), Candida parapsilosis, Candida tropicalis, Candida krusei
- Molds: Scopulariopsis brevicaulis, Hendersonula toruloidea, Aspergillus sp., Alternaria tenuis, Cephalosporium, Scytalidium hyalinum
- Dermatophytes cause 90% of toenail and most of fingernail onychomycoses.
- Yeasts, especially Candida, may involve fingernails (not uncommonly) or toenails.
- Dermatophytes can invade normal keratin, whereas nondermatophyte molds invade altered keratin (dystrophic/injured nails).
Risk Factors
Risk Factors
Risk Factors
- Older age
- Tinea pedis
- Occlusive footwear
- Cancer/diabetes/psoriasis
- Peripheral vascular disease
- Cohabitation with others with onychomycosis
- Immunodeficiency
- Communal swimming pools
- Smoking
- Peripheral vascular disease
- History of nail trauma
- Autosomal dominant genetic predisposition
General Prevention
General Prevention
General Prevention
- Keeping feet cool and dry
- Avoiding occlusive footwear
- Using sandals in public locker rooms and swimming pools
- Discarding or treating of infected footwear and socks (2)
Commonly Associated Conditions
Commonly Associated Conditions
Commonly Associated Conditions
- Immunodeficiency/chronic metabolic disease (e.g., diabetes)
- Tinea pedis/manuum
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