13 Cases of Leukoderma Punctata after Narrowband UVB Therapy in Vitiligo Patients

Back, Seung Ju; Park, Young Ok; Won, Young Ho; Seo, Young Joon; Lee, Jeung Hoon; Park, Jang Kyu

Abstract

BACKGROUND: Leukoderma punctata is a peculiar disorder with punctiform, hypopigmented and achromic spots. Histopathologically, a focal reduction of melanocytes and melanin granules are found in the depigmented macule. The phototoxic effect of phototherapy on melanocytes has been suggested as the most likely cause. This occurs mostly after application of systemic or topical psolaren on photochemotherapy. However, a case following narrowband UVB therapy is very rare.
OBJECTIVE
The purpose of our study was to investigate the characteristics of leukoderma punctata patients and find the cause of leukoderma punctata.
METHODS
We reviewed the medical records of leukoderma punctata patients, and a skin biopsy was taken from punctiform hypopigmented macules. The tissues were stained with hematoxyline and eosin, Fontana-Masson, and dopa-oxidase.
RESULTS
The average age of patients was 51 years old. There was no difference between results of male and female patients. Involvement sites of patients were mostly the arms and legs. 76% of patients did not have preceding subjective symptoms. In eight of nine patients, a marked reduction of melanin and melanocytes was noted with both Fontana-Masson staining and dopa-oxidase staining. The average total period of PUVA therapy was 26 months and average total dose of PUVA irradiation was 351.2 J/cm2 in leukoderma punctata patients. Before leukoderma punctata developed, the average total period of narrowband UVB therapy was 6.9 months and average total dose of narrowband UVB was 22.45 J/cm2. The results suggest that leukoderma punctata developed in very small dose of narrowband UVB, although it did not develop with large doses of PUVA.
CONCLUSION
Narrowband UVB (311 nm) is the most likely spectrum for development of leukoderma punctata.