Patient Dermatology Education

Post-Inflammatory Hyperpigmentation (PIH)

Post-Inflammatory Hyperpigmentation (PIH)

Chere Lucas, MD

What is PIH?
Post-inflammatory hyperpigmentation (PIH) occurs after there is damage or irritation to the skin. The skin involved turns tan, brown, or purple, which brings about the term hyperpigmentation (more color). It is very common in skin of color with over 65% of African Americans experiencing symptoms.1

What causes PIH?
Irritation or damage to the skin, can lead to post-inflammatory hyperpigmentation. Skin of color has more pigment (melanin) so there is more of a chance of PIH with certain skin problems. Skin problems that often result in PIH include acne, burns, eczema (atopic dermatitis), allergic reactions, infection, insect bites, lichen planus, pseudofolliculitis barbae, and psoriasis.

PIH can be epidermal (top layer of skin), dermal (deeper layer of skin) or mixed. This classification is based on the depth of hyperpigmentation in the skin visualized on clinical exam or with the use of Wood’s lamp examination or biopsy (removal of skin tissue for examination). Epidermal PIH is the most amenable to treatment with topical regimens. Mixed and dermal melasma are very difficult to treat due to the presence of deeper pigment.

How can PIH be treated?
Post inflammatory hyperpigmentation can take months to years to fully clear. For effective long-term treatment of PIH, it is essential to treat the underlying skin problem that is leading to the discoloration. In addition, certain treatments can speed up the process, such as topical hydroquinone, retinoid, corticosteroid, azelaic acid, glycolic acid, kojic acid, along with procedures such as microdermabrasion and light chemical peels.

Dermal PIH is more difficult to treat and may require more aggressive therapy such as chemical peels and/or laser surgery, which include a risk of worsening the pigmentation.

Sunlight can cause PIH to darken, so it is important to utilize protection from the sun (sunscreen, sun-protective clothing) on the areas involved.

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1. Love PB, Kundu RV. Clinical cases in skin of color medical, oncological and hair disorders, and cosmetic dermatology [Internet]. 2016 [cited 2016 Feb 29].

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