Post-inflammatory hyperpigmentation is darkening of skin after inflammation or injury. It doesn’t itch or hurt, but it can be bothersome and worsens with sun exposure. Over-the-counter treatments plus daily sun protection can help fade it.

Melasma is a blotchy brown darkening of facial skin, often called the “mask of pregnancy” because it can appear during or after pregnancy. Sun makes it worse, but over-the-counter treatments combined with daily sun protection can help.

Acanthosis nigricans is dark, thick, velvety skin, usually on the neck, armpits, groin, or under the breasts. It doesn’t itch or hurt but can be noticeable. Eating healthier, using topical retinoids, and mild acids can help improve it.