Nail dermoscopy (onychoscopy) is useful in diagnosis and treatment follow-up of the nail mixed infection caused by Pseudomonas aeruginosa and Candida albicans

Nail dermoscopy (onychoscopy) is a non-invasive diagnostic tool helpful in differential diagnosis of nail apparatus pigmentation. In the Caucasian population melanocytic melanonychia occurs relatively rarely. More common causes (about 80%) of dark nail pigmentation are haematomas and nail infections [1]. From the clinical point of view, it is important to distinguish between these conditions to avoid unnecessary biopsies. Onychoscopy is a simple, non-invasive tool which supports the clinical diagnosis. Dermoscopic features of nail pigmentation caused by melanocytic lesions (melanonychia) are described and also the dermoscopic pattern of the nail apparatus melanoma is established. In contrast, there are only a few reports of dermoscopic features of the nail pigmentation caused by infectious agents [2–4]. Similarly, dermoscopic features of mixed nail infections due to Pseudomonas aeruginosa (P. aeruginosa) and Candida albicans (C. albicans) have not been previously reported. We present two illustrative cases indicating the usefulness of dermoscopy in differential diagnosis of infectious and melanocytic nail pigmentation as well as its possible application in treatment follow-up of mixed nail infections