Abstract
AbstractHistological incontinence of pigment (HIP) was studied using light and electron microscopy in a pigmented lesion from a female facial melanosis (FFM) patient and in another lesion produced by isoeugenol when the patient was patch tested. The following sequence of events is thought to underlie HIP. Phagocytes invade the epidermis and phagocytize melanosomes either in keratinocytes or in cytoid bodies, which are degenerated keratinocytes. These phagocytes then return to the dermis through gaps in the basal lamina.In brown guinea pigs sensitized to DNCB, 0.02% DNCB in acetone was applied repeatedly to the same area of the abdomen once per week for six weeks. HIP was observed in 28% of the animals following the fifth application of DNCB. In contrast to the HIP process observed in the patient, phagocytes in brown guinea pigs phagocytized free melanosomes. In irritant reactions to DNCB in brown guinea pigs, only concentrations which produced epidermal necrosis induced HIP.
Published Version
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