When to worry about dark patches on skin with post-inflammatory hyperpigmentation

Post-inflammatory hyperpigmentation is darker colour left after inflammation or injury, such as acne, eczema, a rash, a burn, or a procedure. The skin may look flat even after the original problem has settled. Colour can be more noticeable after sun exposure or renewed irritation, and the shade may differ from the surrounding skin.

Treat the original skin condition as advised and avoid picking, friction, and harsh exfoliation. Protect the area from sunlight and use a bland moisturiser if the skin is dry or sensitive. Keep a note of the original trigger and photograph the mark occasionally; this helps a clinician tell a stable leftover mark from a new process.

Book an assessment if the patch keeps expanding after the inflammation has settled, becomes raised, scaly, tender, very itchy, crusted, or bleeds, or appears without a preceding skin problem. Seek prompt advice if several new patches emerge with ongoing rash, swelling, or infection symptoms. A rapidly changing lesion should be examined rather than treated only with lightening products.

Ask whether the mark fits post-inflammatory hyperpigmentation, whether the original trigger needs further treatment, and which options are appropriate for your skin. Ask how to prevent renewed inflammation and what change should prompt a follow-up.