skin disorders
Hyperpigmentation
Localized hyperpigmentation
Localized hyperpigmentation can be caused by Skin injuries Skin inflammation Reactions to sunlight Abnormal skin growths Hyperpigmentation can develop after injuries such as cuts and burns or inflammation caused by disorders such as Acne and Some people develop hyperpigmentation in areas of skin that have been exposed to sunlight. Some plants (including limes, celery, and parsley) contain compounds called furocoumarins that make some people's skin more sensitive to the effects of ultraviolet light. This reaction is called phytophotodermatitis (see Chemical photosensitivity ). Hyperpigmentation can also occur in Melasma , People who have a disorder called acanthosis nigricans develop darkened and thickened skin in the underarms, on the nape of the neck, and in skinfolds. Acanthosis nigricans can be a symptom of diabetes. 