Clinical and mycologic characteristics of onychomycosis in diabetic patients

The aim of the study was to examine the relative prevalence of dermatophytic, yeast and non-dermatophytic mould onychomycosis among diabetic patients, and to compare it with nondiabetic patients. The study included 460 consecutive diabetic patients and the same number of nondiabetic age-matched subjects attending dermatology clinics at Farwaniya Hospital, Kuwait, over a period of 4 years. All patients were examined clinically and mycologically for any evidence of onychomycosis. All cases of clinically suspected and/or mycologically proven onychomycosis were prescribed terbinafine tablets 250 mg orally per day continuously for 6-12 weeks. The prevalence of clinical onychomycosis in the diabetic and control group was 18.7% (86 cases) and 5.7% (26 cases), respectively. Elderly diabetic patients were at an increased risk of developing onychomycosis. Toenails were affected in 54 (62.8%), fingernails in 20 (23.3%), and both fingernails and toenails in 12 (14%) cases in diabetic group. Distal subungual onychomycosis was the most common clinical presentation, recorded in 67.4% of patients, followed by total dystrophic onychomycosis in 11.6% of patients. Culture positivity alone was seen in 16 (18.6%), both culture and KOH positivity in 52 (60.5%), and positive KOH alone in 10 (11.6%) cases; 8 cases had negative KOH examination and culture, but were PAS positive. Dermatophytes were the most common isolate. Seven percent cases treated for onychomycosis from the diabetic group were evaluated as unsuccessful (relapsed) at the end of the study. This study confirmed that diabetic patients are at a high risk of having or contracting onychomycosis. Onychomycosis was found to correlate significantly with increasing age and male gender. These findings reinforce the importance of attending to infections in diabetics to reduce the associated morbidity. Managing onychomycosis in diabetics may require systemic antifungal treatment, physical measures and patient education.