What are the risk factors for post-inflammatory hyperpigmentation?

Inflammation can signal pigment-producing cells to release extra melanin. The affected area may then look brown, grey, or darker than nearby skin after the original rash, spot, bite, or wound settles. Acne is a very common trigger; atopic dermatitis, insect bites, scratches, shaving irritation, and cosmetic or heat injuries can also leave marks. A deeper or longer-lasting injury, repeated rubbing, and picking at a spot increase the chance of a noticeable mark. Sun and visible light can deepen existing pigmentation.

Treat the inflammation early with advice suited to your skin, and avoid squeezing, scratching, or repeatedly rubbing the area. Use gentle, fragrance-free cleansing and moisturising while the skin heals. Protect exposed skin with broad-spectrum sunscreen and reapply as directed, especially outdoors; hats and shade add useful protection. Do not start strong lightening products on broken or actively inflamed skin. A clinician can assess the cause and choose options that reduce irritation.

Arrange a dermatology review if the dark patch is growing, changing in colour or texture, bleeding, painful, or not clearly linked to a healed injury. Seek prompt care for spreading redness, warmth, pus, fever, or rapidly worsening swelling. Persistent marks after acne or dermatitis may need treatment of the underlying inflammation before pigment-focused care is considered.

Which trigger is most likely in my case? Could my current skin treatment be causing irritation? What sun protection and pigment care fit my skin tone? How should I handle a new inflamed spot to reduce marking?