TL;DR
Hypertrophic scars stay within the borders of the original wound and usually flatten over 12 to 24 months. Keloids grow beyond the wound edge, often years after the injury, and rarely resolve on their own. Silicone is the first-line topical for both. After that, the treatment trees split: hypertrophic responds well to massage and steroid injection, keloids need careful clinical management and have a real recurrence rate.
Both look raised, both look angry, both can itch or sting. But the underlying biology is different enough that the same routine can settle one and provoke the other. The piercing scar on your friend’s shoulder that has been a quiet pink line for a year is probably hypertrophic. The lentil-sized dome that grew out of a tiny chest pimple and is now the size of your fingernail is almost certainly a keloid.
Hypertrophic scars: what they do well
A hypertrophic scar stays politely inside the lines. It rises above skin level, often pink or purple, sometimes itchy, but it respects the boundary of the original cut, burn, or acne lesion. It usually peaks in size and redness around three to six months post-injury, then slowly settles. Two-thirds of hypertrophic scars flatten within 24 months without specific intervention, especially if you keep them out of direct sun and protect them from tension.
The collagen biology is overactive but contained. Type III collagen lays down too thickly inside the wound bed but the local fibroblasts know when to stop. Treatment is supportive. Silicone sheets or silicone gel worn 12 to 23 hours a day for at least two months is the most-studied topical, with around 50 percent reduction in scar height in trials going back to the 1980s. Pressure massage, scar-massage protocols starting at week six, and avoidance of UV exposure during the remodeling phase all help. Stubborn hypertrophic scars respond well to a single intralesional triamcinolone injection or to pulsed-dye laser for the redness component.
Keloids: what they do well (in their own annoying way)
A keloid does not respect the wound. It crawls outward, sometimes years after the original injury, into healthy skin. It is firm, often shiny, often hyperpigmented. It can be tender or itchy or painless. It rarely flattens on its own and the recurrence rate after surgical excision alone is between 45 and 100 percent depending on the site. Keloids run in families, and there is a strong genetic component associated with people of African, Hispanic, and East Asian ancestry. The chest, shoulders, earlobes, and jawline are the most common sites.
The fibroblasts in keloid tissue are functionally different. They overproduce type I and III collagen, lay it down chaotically, and resist the normal apoptotic signals that tell wound fibroblasts to stop. This is why a keloid that gets cut out can grow back larger. Treatment is multi-modal. Silicone first, intralesional triamcinolone every four to six weeks, sometimes combined with 5-fluorouracil, sometimes cryotherapy, sometimes surgical excision followed immediately by adjuvant radiation in serious cases. The skin of color tag hub goes deeper into the genetics and the unique scarring considerations.
How to choose your approach
First, identify which one you have. Does the lesion stay inside the original wound borders? Hypertrophic. Does it bulge beyond the original wound, especially with a claw-like or pseudopod edge? Keloid. Did it appear within months of the injury and start settling within a year? Hypertrophic. Did it keep growing past the one-year mark, or appear up to five years after the original injury? Keloid.
For hypertrophic: silicone gel or sheet daily, sun protection, gentle massage starting at six weeks, and a single steroid injection at month three if it has not started softening. Most settle without anything more aggressive.
For keloids: silicone gel daily but go to a dermatologist early. Do not let a fresh keloid get treated as a cosmetic problem you can wait out. Early intralesional steroid every four to six weeks for the first six months gives the best long-term outcomes. Never let a keloid be excised without a clear adjuvant plan, since lone excision is the single most reliable way to make one grow back larger.
The contrarian view
Skincare content treats all scars as a single category and pushes the same vitamin E plus silicone routine at everyone. Two problems with that. Vitamin E topically has weak evidence for scar improvement and a meaningful rate of contact dermatitis (a 1999 Dermatologic Surgery study showed 33 percent of users developed dermatitis, with no measurable improvement over petrolatum). And the same routine cannot work for both because the conditions are not the same problem at scale. Keloid-prone skin is a genetic predisposition that deserves a doctor, not a serum.
Real numbers
A 2014 meta-analysis in Burns & Trauma covering 26 randomized trials and 1,481 patients found silicone gel sheeting produced a 56 percent average reduction in hypertrophic scar height after eight weeks. The same review found silicone alone was significantly less effective on keloids (around 23 percent improvement) and that combined silicone plus monthly intralesional triamcinolone produced a 73 percent reduction in keloid height over 12 weeks. For more on related skin concerns, see atrophic acne scars (the opposite kind of scarring) and the microneedling at home review, which has important warnings for anyone keloid-prone. The 14-day barrier repair plan applies if your scar zone gets irritated from overzealous topical use.
FAQ
Can I use retinol on a fresh scar? Wait three months. Retinol on remodeling tissue can prolong redness and is not the right tool while the wound is still rebuilding.
Does massage actually help? Yes for hypertrophic, modest evidence for keloids. Start at six weeks post-injury, two minutes twice a day, gentle circles.
What about onion extract gels? Studied in keloid prevention with mixed results. Silicone outperforms it head-to-head in most trials.
Will sunscreen prevent scar darkening? Yes. UV is the single most actionable risk factor for permanent scar pigmentation. Cover daily for at least 12 months.
Can a piercing keloid be saved? Sometimes, with early intralesional steroid. Once it is older than two years, options narrow.
Sources: Burns & Trauma meta-analysis on silicone for scar management (2014); American Academy of Dermatology, Keloid Overview; Dermatologic Surgery on vitamin E in postoperative wound healing (1999).