Postinflammatory Hyperpigmentation Workup

Updated: Apr 05, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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Laboratory Studies

A Wood lamp examination enables distinction of epidermal postinflammatory hyperpigmentation (PIH) from dermal postinflammatory hyperpigmentation. Epidermal lesions tend to have accentuated borders under a Wood lamp examination, whereas those of dermal lesions appear poorly circumscribed and are not accentuated with a Wood lamp examination.



If a history of preceding inflammatory dermatosis is unclear or absent, skin biopsy is warranted to exclude other underlying causes of hyperpigmentation. Staining of the biopsy specimen with Fontana-Masson silver stain for melanin enables localization of the melanin in the epidermis and/or the dermis.


Histologic Findings

Epidermal postinflammatory hyperpigmentation involves increased melanin pigment in the basal cell layer of the epidermis. Occasionally, giant melanosomes are evident in the epidermis.

Dermal postinflammatory hyperpigmentation involves melanin pigment in the upper dermis, with pigment incontinence due to increased numbers of melanophages in the papillary dermis.