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Background: Phototherapy is a well-known method to treat vitiligo and is able to repopulate the skin with new melanocytes. Examination of the pathological changes in vitiligo after ultraviolet therapy revealed the presence of unusual cells., Aim of Study: This study intended to investigate and confirm the repopulation of epidermis with new spindle cells, possibly as precursors for melanocytes after UV therapy., Methods: Retrospective study was carried out on paraffin sections of biopsies obtained from 30 vitiligo patients treated successfully with ultraviolet therapy. Routine, special and immune staining were utilized to examine these biopsies., Results: Amelanotic spindle cells with slightly eosinophilic cytoplasm and dark flattened nuclei were characteristically demonstrated in all examined sections after ultraviolet therapy. These cells were abundant near infundibular portion of hair follicles. They subsequently developed dendrites and became melanized., Conclusions: Melanocyte precursors can be demonstrated pathologically and immunologically on tissue samples after ultraviolet therapy. They are capable of proliferation and migration into depigmented epidermis to repopulate it with new generations of melanocytes., (© 2013 European Academy of Dermatology and Venereology.)

Background and Aims: Vitiligo is an acquired pigmentary disorder of skin and hair. Active melanocytes in hair follicles can be detected by DOPA and immunohistochemical staining, while amelanotic melanocytes can only be detected by the latter. None of the studies on hair melanocytes in vitiligo discussed the effect of disease duration on these melanocytes. Here, we study the presence of melanotic and amelanotic melanocytes in vitiligo hair follicles and statistically correlating their presence with the disease duration., Methods: This study was conducted on 30 patients with vitiligo and 10 normal volunteers. Three biopsies were taken from each patient: two from black and white hairs from vitiliginous areas and the third from apparently normal skin of the same patients. Sections were stained by DOPA reaction and NKI/beteb then examined for the presence of melanocytes. The presence of melanocytes and the disease duration were correlated statistically using the t-test., Results: Active melanocytes were detected in black hairs of 6.7% of vitiligo patients and in 100% of apparently normal skin of the same patients and controls. On examining black hairs of the 28 vitiligo patients with negative DOPA reaction, 19 of them (67.9%) showed positive NKI/beteb stain. Disease duration was inversely correlated with the melanocytes' presence within hair follicles. Melanocytes were absent from 100% of white hairs., Conclusions: The melanotic melanocytes were the first target of the disease process followed by the amelanotic melanocytes. Since the disappearance of the latter was inversely correlated with the disease duration, early treatment in vitiligo is advised.