Onychomycosis is fungal infection of the nails. This may be caused by

• dermatophytes - mainly Trichophyton rubrum, accounts for 90% of cases
• yeasts - such as Candida
• non-dermatophyte moulds

Risk factors include for fungal nail infections include diabetes mellitus and increasing age.

PC

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

Differential diagnosis

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

Investigation

• nail clippings
• scrapings of the affected nail