Hypertrophic and Keloid Acne Scars: Why Some Acne Scars Are Raised, and How They Are Treated

When a deep acne lesion heals, the skin lays down collagen to repair the damage. In most people on most parts of the face, the repair falls short and the surface sinks — the familiar rolling, boxcar and ice pick scars. In some people, and in some locations, the repair overshoots: fibroblasts keep producing collagen after the wound has closed, and the scar rises above the skin as a firm, often pink or darker lump. Whether a given lesion heals up or down depends on genetics, skin tone, the tension on the skin at that site, how deep and prolonged the inflammation was, and whether the lesion was picked or squeezed.

This is why raised acne scars cluster on the jawline, chest, shoulders and upper back — areas of thicker skin under constant tension, where acne tends to be nodular and deep — and why they are more common in people with medium to dark skin and in those who have formed keloids elsewhere.

Both are raised, firm collagen overgrowths, and the distinction matters because expectations and protocols differ. A hypertrophic scar stays within the boundary of the original lesion, tends to appear within weeks of healing, may be red and itchy at first, and often softens and flattens on its own over one to two years. A keloid grows beyond the original boundary into surrounding normal skin, may appear months after the lesion healed, keeps growing rather than regressing, and commonly itches, burns or is tender. Keloids rarely resolve without treatment and have a strong tendency to recur after it.

A doctor also looks at the number and pattern of raised lesions. Scattered firm papules across the jaw or back after nodular acne behave like hypertrophic scars; a few large, spreading, symptomatic lumps on the chest or shoulders behave like keloids. At the back of the neck, persistent firm bumps after folliculitis are a distinct condition (acne keloidalis nuchae) that needs its own approach.

The core treatment for both is intralesional corticosteroid injection: a small volume delivered directly into the scar tissue, which suppresses the overactive fibroblasts, softens the collagen and relieves itch. Sessions are short and repeated every four to six weeks; small, young scars may flatten after a few, while large or old keloids need a longer course. Other agents are sometimes combined with or substituted for steroid in resistant scars. Laser is added when colour or surface texture persists after flattening — a vascular laser for redness, a fractional device for texture — and pico laser for residual pigment on darker skin.

Surgical excision is reserved for selected keloids, such as narrow-based lumps, and is always paired with injections around the procedure, because cutting a keloid out alone re-injures keloid-prone skin and the scar frequently regrows larger. Silicone gel or sheets support treatment between sessions and help young hypertrophic scars, but are not a treatment for an established keloid. Pressure, taping and avoiding further trauma to the area all help maintain the result.

Many people with severe acne carry both: dents on the cheeks and temples, lumps along the jaw or on the back. The plans run in parallel but do not mix — the raised scars are injected and calmed, the depressed scars are released and resurfaced — and the sequencing matters, because resurfacing energy near an active keloid can provoke it. A doctor maps both populations and plans the order. The other essential is acne control: as long as deep lesions keep forming, new raised scars keep forming behind the treated ones.

Any raised scar that is growing beyond its original spot, itching persistently, painful, or has not softened after a year is worth an assessment — early keloids respond to fewer sessions than established ones. So is a raised scar you are tempted to cut, pick or treat with an aggressive home remedy, all of which make keloids worse. DrPlus assesses and treats raised scars at the Johor Bahru clinic in Iskandar Puteri and at three Singapore clinics — Tanjong Pagar, East Coast and Novena. You can send a photo first for a preliminary view; a written plan and quote follow the in-clinic assessment, with no obligation to proceed. Results vary by individual.