How to fade post inflammatory hyperpigmentation

What causes post inflammatory hyperpigmentation

Post inflammatory hyperpigmentation, or PIH, is a flat dark mark left after inflammation or injury prompts the skin to make extra melanin, the pigment that gives skin its color. It can follow acne, eczema, psoriasis, a bite, a cut, a burn, irritation from a skin or hair product, or some medicines. Hormonal changes, including pregnancy, can also trigger dark spots. A flat brown mark can outlast the pimple that caused it, because skin apparently keeps a longer filing system than the rest of us.1

What to do

1. 1Treat the cause. If acne, eczema, or psoriasis is active, address that condition first. When the inflammation settles, many spots fade on their own, though the wait can be long.
2. 2Remove sources of irritation. If a skin or hair product is irritating your skin, switch to gentler products. Stop using a product that burns or stings when you apply it. If you think a medicine is causing dark spots, ask the prescribing doctor about it rather than stopping the medicine yourself.
3. 3Protect exposed skin every morning. Before going outside, apply a broad spectrum, water resistant sunscreen with SPF 30 or higher to skin not covered by clothing. A tinted sunscreen with iron oxide also protects against visible light, which can contribute to dark spots. Choose one that blends with your skin tone to avoid a white cast, so protection need not arrive wearing a costume.
4. 4Reapply sunscreen every two hours and after swimming or sweating. A wide brimmed hat adds protection while you are outdoors.
5. 5Add a fading ingredient if you want to treat marks directly. Over the counter options include azelaic acid, glycolic acid, kojic acid, a retinoid such as retinol or adapalene, or vitamin C. These ingredients can fade existing spots; some can also slow melanin production.
6. 6Avoid picking, popping, scratching, or squeezing acne. Those actions increase inflammation and the chance of discoloration and scarring.

Sunscreen has the clearest role in prevention. A systematic review of prevention studies in skin of colour found sunscreen was the most consistently successful measure. The evidence has limits: the review included 14 studies, all patients were Asian, and nearly all cases followed laser treatment. That supports sunscreen after procedures in the studied group, not a promise that sunscreen alone will erase every existing mark.3

Using a retinoid for dark marks

Topical retinoids are one option for PIH. They help disperse melanin, and some retinoids also treat acne, which can prevent the original source of new acne marks. For facial acne, topical retinoids are generally applied once daily at bedtime; the schedule for a specific product or prescription can differ, so follow its directions. Retinoids can cause dryness, peeling, irritation, and increased sun sensitivity. Creams tend to be less irritating than gels. Some topical retinoids are not suitable during pregnancy, so check with a health professional before using one if you are pregnant.4

How long fading takes

A spot only a few shades darker than your natural skin color often fades within 6 to 12 months once its cause has stopped. Deeper pigment can take years to fade and may look slate blue or gray, or much darker brown than your natural skin color. Treatment can speed fading, but some hyperpigmentation is difficult to treat because pigment in deeper skin layers can be hard for topical products to reach. New spots can still form if the trigger returns.15

When to see a dermatologist

See a dermatologist if you cannot identify the cause, new marks keep appearing, or your treatment is not giving the result you want. Some spots need prescription treatment, and a dermatologist can choose an approach based on the cause and depth of the pigment. Do not use liquid bleach on dark spots. If you suspect a medicine is involved, ask the doctor who prescribed it whether a different medicine is an option.1

Acne marks vs acne scars

A flat spot of color after acne clears is usually PIH, not an acne scar. An acne scar changes the skin's shape by leaving a depression or raised area. The color around a scar can fade while the change in texture remains, which is a needlessly confusing exit interview. PIH can improve over months or longer; acne scars rarely disappear completely on their own.26