The prevalence of onychomycosis among diabetic patients is still a debated question as well as the best way to diagnose the disease. We conducted a prospective study to assess the prevalence of onychomycosis in diabetic neuropathic (DN) patients clinically suspected of this disease and to assess the reliability of the diagnosis of onychomycosis.

From December 2000 to January 2005, we followed 100 successive diabetic patients, type 1 and type 2, suffering from (DN). At baseline we assessed age, gender, medical history and medications, foot insensitivity defined by a vibration perception threshold (VPT) >25 volts and onychomycosis by clinical diagnosis.

Multiple samples of the most affected nail, often the big toe, were taken. A potassium hydroxide (KOH) test was done by 2 independent and blinded investigators and a culture in a laboratory (lab) specialized in mycology.

Pictures of the nails and particularly of the sampled nail were taken. Apart from the laboratory results, two independent and blinded dermatologists gave their diagnosis looking at the pictures.

Inclusion Criteria:

• Inclusion criteria were: presence of diabetes mellitus, type 1 or type 2, age between 18 and 80 years, neuropathy demonstrated by a VPT (Vibration Perception Threshold) >25 volts tested with a neurothesiometer (Horwell Scientific, London, UK) and a clinical diagnosis of onychomycosis.

Exclusion Criteria:

• Exclusion criteria were a history of psoriasis, systemic antifungal therapy during the year preceding the enrolment, immunosuppression either by disease or treatment induced.