What is the term for abnormal pigmentation of the skin?

The term for abnormal pigmentation of the skin is dyschromia. Dyschromia refers to any change in skin color, which can manifest as hyperpigmentation (darkening of the skin) or hypopigmentation (lightening of the skin). This condition can result from a variety of factors, including sun exposure, hormonal changes, inflammation, or underlying medical conditions.

Dysplasia refers to abnormal growth or development of cells and tissues and is not specifically related to pigmentation. Dermatitis is an inflammation of the skin that often results in redness and itchiness but does not specifically denote abnormal pigmentation. Dermatofibroma is a type of benign skin tumor that is usually firm and may be pigmented, but it is not a term for pigmentation changes in general. Thus, dyschromia is the most accurate term for describing abnormal pigmentation of the skin.