DESCRIPTION
Onychomycosis is one of the commonest dermatological
conditions. A large questionnaire survey of 10 000
people suggested a prevalence of 2Æ71% in the U.K.1,2
More recent mycologically controlled surveys in Finland
3 and in the U.S.A.4 indicate a prevalence of
between 7 and 10%. Increasing publicity about disease
prevalence, and the advent of new and more effective
antifungal drugs, has led to a greater enthusiasm
among sufferers to seek treatment and among medical
practitioners to institute therapy. However, treatment
is often prescribed without mycological confirmation of
infection, there may be confusion as to whether fungi
isolated on culture are primary or secondary pathogens,
the relative efficacy of different antifungal agents
against different fungi is not completely understood
and drugs are often prescribed for inappropriate treatment
durations.
Definition
Onychomycosis is an infection of the nail apparatus by
fungi that include dermatophytes, nondermatophyte
moulds and yeasts (mainly Candida species). The
toenails are affected in 80% of all cases of onychomycosis;
dermatophyte infection, mostly due to Trichophyton
rubrum, is the cause in over 90% of cases.5
Onychomycosis is classified clinically as distal and
lateral subungual onychomycosis (DLSO), superficial
white onychomycosis (SWO), proximal subungual
onychomycosis (PSO), candidal onychomycosis and
total dystrophic onychomycosis.