Postinflammatory Hyperpigmentation



Postinflammatory Hyperpigmentation


Marita Kosmadaki

Andreas Katsambas



BACKGROUND

Postinflammatory hyperpigmentation (PIH) is an acquired macular pigmentation resulting from prior skin inflammation or trauma. It is a common disorder; it may appear at any age and on any skin location, including mucous membranes and nails. It affects equally men and women but is more frequent and intense in darker skin phototypes.


PRESENTATION

PIH presents with one or more hyperpigmented macules or patches at sites of prior skin inflammation or trauma. PIH tends to improve with time and usually lasts from months to years; however, some cases of dermal PIH may be permanent. It may worsen with ultraviolet (UV) irradiation or with persistent or recurrent inflammation.




PATHOGENESIS

Common dermatoses such as acne, allergic contact or irritant reactions, lichen planus, psoriasis, dermatophytoses, insect bites, and viral exanthems may all result in PIH. Skin irritation from topical drugs, trauma, or friction are also PIH causes. Importantly, cosmetic procedures can produce PIH, including lasers, intense pulsed light (IPL), chemical peels, cryosurgery, and microneedling. The borders of the anatomic areas involved correlate with the location of the preceding trauma or area of prior treatment that induced the PIH.

The exact pathogenesis of PIH remains unknown. It is likely that the inflammatory process stimulates the release of cytokines and inflammatory mediators, including leukotrienes, prostaglandins, and thromboxane,2 that in turn stimulate increase in melanin production and transfer of melanin to surrounding keratinocytes (epidermal PIH). The dermal component of PIH results from damaged basement membrane and melanin “fall” into the dermis, where it is phagocytosed by macrophages (subsequently called melanophages). It is also believed that macrophages may migrate into the epidermis, phagocytose melanosomes, and then return to the dermis.

Jun 29, 2020 | Posted by in Dermatology | Comments Off on Postinflammatory Hyperpigmentation
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