The rationale for combination therapy.

Fungal infections of the nail are common in European populations. There are a number of clinical presentations usually resulting from an infection by one of the dermatophyte species, notably Trichophyton rubrum. A number of modern treatment strategies are available and are generally well tolerated and effective. However, a significant proportion of patients, 20-30%, can expect treatment failure and/or relapse following treatment. The search for new treatment modalities and drugs is hampered by our lack of understanding of the basic pathophysiological mechanisms that underlie these frequently encountered infections. A correct diagnosis is key to the implementation of successful treatment. Even then, some infections do appear to be more recalcitrant than others. This may be the result of a number of interacting factors: patient susceptibility, fungal growth patterns that resist treatment and the occurrence of dormant fungal spores (arthrospores) in the nail. Increasingly, research is turning towards the identification of clinical indicators of poor prognosis and the development of new treatment strategies to overcome them. The combination of drugs to produce synergistic activity is one possible advance towards achieving higher cure rates.