Vascular response in halo of recent halo nevus.
The depigmented halo of a recently acquired halo nevus showed prominent erythema. Microscopic examination of a specimen from the halo showed dilatation of the dermal blood vessels, thickening of the vessel walls, and swelling of the endothelial cells; cellular infiltration was totally absent. Direct immunofluorescent studies on skin from the halo failed to show vessel, basement membrane, or intercellular fluorescence with IgG, IgM, IgA, C3, and fibrin. We conclude that the erythema in the skin of the depigmented halo is the result of dilated dermal blood vessels and that the mechanism of vascular dilatation is not associated with direct infiltration by inflammatory cells nor with immune complex formation. Erythema in the skin of the depigmented halo has not, to our knowledge, been studied previously.
D000328:Adult; D004108:Dilatation, Pathologic; D004890:Erythema / Q000473:pathology; D006801:Humans; D008297:Male; D009508:Nevus, Pigmented / Q000473:pathology*; D012867:Skin / Q000098:blood supply* / Q000473:pathology