MORPHOLOGIC OBSERVATIONS ON THE DERMAL NERVES IN VITILIGO - AN ULTRASTRUCTURAL-STUDY

Background. Vitiligo is a common idiopathic skin disorder. The etiolog y is unknown, although Various hypotheses have been advanced. These in clude the neuronal hypothesis, where neuronal factors are thought to p lay a role in the pathogenesis of this disease. Methods. Skin biopsies were taken from marginal and central parts of four vitiligo patients. Biopsies were also taken from nonvitiliginous skin of each patient an d from four normal control subjects. Sections were examined under the electron-microscope. Nerve fibers in the superficial dermis were exami ned. Results. Subtle ultrastructural changes, including regeneration a nd degeneration, were consistently found in dermal nerves of vitiligo lesions. The most consistent feature, seen in all four vitiligo patien ts studied (in both lesional and marginal areas), was an increased thi ckness of the basement membrane of Schwann cells. This change was foun d in approximately three-quarters of all dermal nerves in vitiligo bio psies, but in only about one-quarter of dermal nerves in normal contro l skin. About half the abnormal dermal nerves in vitiligo skin showed minor axonal damage, although indicators of regeneration (increased mi tochondria and rough endoplasmic reticulum) predominated. The dermal n erves in vitiligo showed no difference in fiber diameter or fiber dens ity in comparison with controls. Conclusions. In vitiligo both axonal degeneration and nerve regeneration may occur, with the latter possibl y being a reactive change to earlier axonal damage. These findings sup port the hypothesis that there is a neuronal component to this disease .