Psoriasis with Onychodystrophy in a 7-Year-Old Boy

Up to 90% of patients with psoriasis develop onychodystrophy at some point during their lives. Nail involvement precedes the skin lesions in approximately 4% of patients. We herewith report a case of a 7-year-old boy with psoriatic onychodystrophy at the age of 6 years followed by the appearance of plaque psoriasis 6 months later. The psoriatic onychodystrophy was initially misdiagnosed as onychomycosis by his family physician and was treated as such. Psoriatic onychodystrophy can clinically mimic nychomycosis and differentiation of the two conditions can be difficult. We emphasize the need for potassium hydroxide examination and culture of nail scrapings/clippings to demonstrate fungal elements, should there be doubt in the diagnosis.