RESUMEN
Onychomycosis is the most common nail disorder in adults. Predisposing factors are immunosuppression, poor peripheral circulation, diabetes mellitus, increasing age, nail trauma, and tinea pedis. Autoimmune patients, who carry many of these predisposing factors, have never been studied. Autoimmune patients, with underlying autoimmune skin diseases; pemphigus, systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), scleroderma, dermatomyositis and cutaneous vasculitis, as well as having abnormal-appearing nail(s) with suspicion of fungal nail infection were included. Clinical information was obtained. The causative organisms were identified by potassium hydroxide preparation and cultured. Duration of onychomycosis in autoimmune patients was twice longer than in non-autoimmune patients. Of those with mycological proven onychomycosis, the autoimmune patients had significantly more affected nails (p < 0.05; chi2, two-sided) compared to the non-autoimmune patients but there was no difference in the affected fingernails or toenails and clinical type of onychomycosis. Candida spp was the most frequently found in autoimmune subjects compared to dermatophytes, Trichophyton rubrum. However, dermatophytes especially Trichophyton rubrum was the most common causative organism in non-autoimmune samples, followed by Candida spp. The causative organisms were more frequently discovered in autoimmune patients, whether by potassium hydroxide (KOH) or culture, than in non-autoimmune patients (p < 0.05; chi2, two-sided).