keloïd

Keloid (also spelled keloïde) is a benign overgrowth of scar tissue that extends beyond the boundaries of a previously injured skin area. It differs from a hypertrophic scar in that it tends to grow larger over time and does not stay within the original wound margins.

Keloids arise from abnormal wound healing, with excessive production of collagen by dermal fibroblasts. They are influenced by cytokines such as transforming growth factor-beta. The scar tissue is usually firm, rubbery, and can be pink, red, or skin-colored. Histology shows thick, disorganized collagen bundles with high cellular activity. They often recur after treatment and may be painful or itchy.

Epidemiology and risk factors: keloids occur more frequently in individuals with darker skin tones and often begin in late adolescence or early adulthood. A family history suggests genetic predisposition. They commonly develop after skin injury, including surgical incisions, ear piercings, burns, acne, or trauma.

Clinical features and sites: the most frequent sites are the earlobes, chest, shoulders, and upper back. Lesions are raised, nodular plaques that may be tender or itchy and can cause cosmetic concerns or restrict movement depending on location.

Diagnosis: diagnosis is usually clinical, based on appearance and history. Biopsy is rarely necessary but may be used to distinguish from other scar or skin conditions.

Treatment and prognosis: there is no cure; management aims to flatten the lesion and reduce symptoms and recurrence. Options include intralesional corticosteroids, silicone gel sheets, pressure therapy, laser therapy (such as pulsed dye laser), cryotherapy, and, when excision is considered, adjuvant radiotherapy or corticosteroids/5-fluorouracil to reduce recurrence. Recurrence after treatment is common, and combination therapies often yield better results than any single modality.