Case of leukoderma punctata after topical PUVA treatment

An 11‐year‐old Korean girl presented with a 2‐year history of asymptomatic multiple punctiform, hypopigmented and achromic spots predominantly on the outer aspect of her right forearm. She had been treated for segmental vitiligo on her right forearm with topical PUVA six times a week for 4 years at a local clinic. The lesions were very distinct, round hypopigmented macules 1–2 mm in diameter, predominantly in nonfollicular distribution ( Fig. 1). Not only the site where topical psolaren had been applied but also areas on her right forearm where UVA was exposed for a long time for treatment of vitiligo developed multiple punctiform hypopigmented spots. She also had PUVA lentigenes on her right forearm. Laboratory studies including complete blood cell count, biochemistry, and endocrinologic studies were all within normal limits. There was no history of inflammatory lesions antedating the hypopigmentation. Skin biopsy was taken from punctiform hypopigmented macules. There were no specific findings in the hematoxylin‐eosin stained sections. However, marked reduction of melanin and melanocytes was noted with the Fontana‐Masson stain ( Fig. 2) and the S‐100 stain ( Fig. 3). With these clinical and histological findings the patient was diagnosed as having leukoderma punctata. 1Multiple, hypopigmented, and achromic spots on the right forearm2Microscopic examination of a hypopigmented macule showing marked reduction of melanin (Fontana‐Masson stain, ×200)3S‐100 stain showing marked reduction of melanocytes in the basal layer (S‐100 stain, ×200)