Abstract
SOME PLAQUES of localized melanosis appear early in life and are probably of prenatal origin. Acquired localized melanosis appears on various parts of the body. Melanosis calorica follows local exposure to heat. Irradiation by ultraviolet rays, alpha rays from thorium X, roentgen or radium rays is followed by melanosis in the exposed area. Certain volatile oils, such as oil of lime, when applied locally sensitize the skin to ultraviolet irradiation, as was reported by Sams.1 Industrial melanosis results in part from photosensitization by various substances derived from crude coal tar and is observed predominantly on exposed surfaces. Postinflammatory melanosis is limited to the areas involved in inflammation. A thermal or chemical burn of the palm is at times followed by a patchy melanotic plaque. Localized melanosis of internal origin is observed in the form of chloasma, often limited to the face and neck. This localized disorder has also

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