Onychomycosis in patients with psoriasis.

The frequency and type of fungal infections of the finger- and toenails was studied prospectively by direct microscopic and culture examinations in dermatological out-patients without psoriasis (n = 41), in patients with psoriasis but no nail involvement (n = 39), and in patients with both psoriasis and nail involvement (n = 39). In these three matched groups the frequencies of dermatophytic nail infections were 10%, 13%, and 13%, respectively, and the frequencies of yeast infections 10%, 10%, and 15%, respectively. These figures were not significantly different. It is concluded that dermatophytic invasion of involved psoriatic nails is not so rare as previously supposed. However, yeast infections are possibly more frequent in involved psoriatic nails as compared with uninvolved and normal nails.