Snapshot A 26-year-old Chinese woman presents to her dermatologist for a persistent growth on her chest. She had previously burned a small portion of her pre-sternal skin while curling her hair 2 years ago. While the burn healed without any problem, she noticed a protuberance where the burn previously was. She reports that this growth seems to be larger than the original burn. On physical exam, she has a 5 cm elliptical firm, pink, and shiny growth. While counselling that this may not go away completely, her dermatologist agrees to start intralesional steroid injections. (Hypertrophic scars) Introduction Clinical definition abnormal and excessive scarring in response to dermal injury, resulting in hypertrophic scars or keloids Epidemiology incidence keloid 6-16% of African population demographics most commonly in ages 10-30 risk factors keloid ↑ in groups with darker skin patients of African, Hispanic, or Asian descent family history wounds on chest, shoulders, upper arms, earlobes, or cheeks hypertrophic scar wounds on areas of high skin tension shoulders, neck, knees, and ankles both dermal injury caused by burns wounds that take > 3 weeks to heal Etiology keloid previous trauma spontaneous hypertrophic scar previous trauma Pathogenesis dysregulation of wound healing recall normal wound healing stages are inflammation, proliferation, and remodeling/maturation keloid ↑↑ type I and type III collagen this is disorganized and extends beyond the original wound abnormalities in melanocyte stimulating hormone may contribute hypertrophic scar ↑ type III collagen this is organized as parallel and confined to the original wound increased activation of myofibroblasts may contribute Prognosis keloid recurrence is frequent will not regress over time hypertrophic scar recurrence is rare may regress over time Presentation Symptoms abnormal scarring occurs after trauma or injury often itchy or painful (keloids > hypertrophic scar) keloid may take months to years to develop hypertrophic scar usually appears within 1 month Physical exam scarring along previous site of wound well-defined, firm, and shiny pink, purple, or hyperpigmented irregular borders Studies Biopsy indications only if clinical diagnosis is uncertain Histology keloid thick collagen fibers with abundant mucoid matrix disorganized type I and III collagen hypertrophic scar thin collagen fibers with minimal mucoid matrix myofibroblasts parallel type III collagen Differential Basal cell carcinoma Treatment Medical intralesional corticosteroid injections indication first-line for treatment that is often used with silicone sheeting silicone sheeting indication first-line for treatment that is often used with intralesional corticosteroid injections Operative surgical excision indication for scars that are associated with contractures Complications Contractures limiting mobility associated with hypertrophic scars