ABSTRACT
Disorders of hyperpigmentation can be congenital or acquired, diffuse or localized. Colour variation may be an important clue to the diagnostic procedure. This chapter presents the most common hyperpigmentation disorders due to genetic factors. It provides acquired hyperpigmentation disorders along with the typical colour presentation. The most common diagnosis of diffuse hyperpigmentation is hyperpigmentation associated with endocrine disorders or drug-induced hyperpigmentation. The epidemiology of hyperpigmentation disorders in a particular region, the clinical characteristics of hyperpigmentation, and a thorough history of the patient will be enough to get a diagnosis in most cases. Histopathology will confirm the diagnosis or provide useful insight on the main disorder in the case of secondary hyperpigmentation. Dermoscopy of hyperpigmented lesions is useful to avoid a biopsy in cosmetically critical areas, such as the face. Examination under Wood's lamp can determine the depth of melanin deposition and level of treatment success.
