Fungal nail infections

Fungal nail infection (onychomycosis) may involve any part of the nail, or the entire nail unit. Toenails are significantly more likely to become infected than fingernails

Causative organisms

• dermatophytes
  • account for around 90% of cases
  • mainly Trichophyton rubrum
• yeasts
  • account for around 5-10% of cases
  • e.g. Candida
• non-dermatophyte moulds

Risk factors

• increasing age
• diabetes mellitus
• psoriasis
• repeated nail trauma

Features

• 'unsightly' nails are a common reason for presentation
• thickened, rough, opaque nails are the most common finding

Extensive dermatophyte infection of a toe nail

Differential diagnosis

• psoriasis
• repeated trauma
• lichen planus
• yellow nail syndrome