Post-Inflammatory Hyperpigmentation (PIH)
Postinflammatory hyperpigmentation is a darkening of the skin that appears at the site of wound or lesion, usually after the original wound has healed.
Conditions or events that may lead to hyperpigmentation include:
- allergic reactions
- skin infections
- mechanical injuries
- reactions to medications
- lichen planus
The area of discoloration can be light brown, red, or black and may become darker if exposed to sunlight or certain medications (such as tetracycline).
Who gets postinflammatory hyperpigmentation?
Postinflammatory hyperpigmentation is most common and long-lasting in dark-skinned people, but it can occur in anyone. It also appears more often in skin conditions triggered by exposure to sunlight, such as phytophotodermatitis and lichenoid dermatoses.
What causes postinflammatory hyperpigmentation?
Postinflammatory hyperpigmentation is the result of inflammation, which leads to the increased production of melanin (skin pigment) in the area where skin is damaged.
How is it treated?
Although the discolored skin will slowly regain its normal appearance, this can take up to a year.
Topical treatments may be recommended to lighten the lesions more quickly, including:
- topical retinoids
- topical corticosteroids
- glycolic acid peels
- azelaic acid
In addition, to prevent further darkening, people with postinflammatory hyperpigmentation should use a broad-spectrum sunscreen on affected areas.
While waiting for treatments to take effect, cosmetics can be used to minimize the appearance of hyperpigmented lesions.