Keloids and Hypertrophic Scars
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Direct answer
A hypertrophic scar stays inside the borders of the wound and settles by itself; a keloid marches beyond them — that single boundary separates the two fibrous overgrowths that dominate scar-clinic conversations, and it decides both prognosis and treatment. Keloids arise weeks to months after injury (or spontaneously after trivial trauma such as ear piercing, acne or BCG vaccination), grow into firm, smooth, claw-like, often itchy or painful masses, favour the sternum, shoulders, earlobes and deltoids, and show a striking predilection for dark-skinned individuals — Indians, Africans and their descendants — with a strong familial tendency. First-line treatment is intralesional corticosteroid (triamcinolone 10-40 mg/mL every 4-6 weeks), with silicone gel sheeting, pressure therapy and cryotherapy alongside; surgical excision alone recurs in more than half of patients, so it is combined with steroids or low-dose radiotherapy. The intraoral mucosa, remarkably, almost never keloids — a fact of daily relevance to dental practice.
What you must remember
- The boundary rule: hypertrophic scar — raised but confined to the original wound, appears within weeks, flattens over 12-18 months, often after burn and tension sites; keloid — extends beyond wound margins into normal skin, appears late (weeks to months), persists and grows, claw-like extensions, does not regress.
- Genetic and racial susceptibility: markedly commoner in dark skin, familial clustering, peak incidence in the second and third decades; the sternum is the single most notorious site, followed by earlobes, deltoids and upper back.
- Common Indian triggers: earlobe piercing (the classical young woman with bilateral bead-like lobular keloids), acne, burns, BCG and other vaccination sites, surgical incisions and even insect bites — in a susceptible person, any dermal injury can seed one.
- Histology in a sentence: keloids show haphazard, thick, eosinophilic collagen bundles (keloidal collagen) with abundant mucopolysaccharide and fibroblast activity beyond the wound — differentiating them histologically is possible though not always sharp.
- Treatment ladder: intralesional triamcinolone acetonide 10-40 mg/mL every 4-6 weeks (first line, response in a majority, atrophy and hypopigmentation as risks); silicone gel sheeting hours daily for months; pressure garments or earrings for earlobes; cryotherapy; excision combined with immediate steroid injection and, for resistant chest wall lesions, adjunct low-dose radiotherapy within 24-48 hours — excision alone recurs in over half the patients.
- Prevention in the susceptible: avoid elective cosmetic procedures in keloid formers (especially piercing), use tension-free closure and buried sutures, place incisions in relaxed skin tension lines, inject steroid at suture removal, and begin silicone or pressure early.
- The dental footnote: oral mucosa almost never forms keloids despite constant minor trauma — one reason intraoral wounds are closed generously; but keloids over the face, mandibular border and neck after maxillofacial surgery are a genuine cosmetic complication in Indian patients.
Two patients, one skin type, two strategies
A 19-year-old presents for keloid removal from both earlobes, present three years after piercing. The counselling is the treatment: if the lobule is simply excised, the odds favour a larger keloid within the year, so the plan is excision followed by immediate and serial intralesional triamcinolone, pressure earrings worn for months, and a warned family — because her younger sister, queued for piercing that season, is the better patient: prevention counsel. Contrast a 45-year-old needing a submandibular incision for gland surgery with a previous sternal keloid after chickenpox: the surgical plan changes pre-emptively — incision aligned to skin tension lines, meticulous tension-free closure with buried absorbable sutures, steroid injection at suture removal, silicone gel from week 2, and review at the first sign of raise rather than after a year of growth. Neither patient can be promised no keloid; both can be promised that the scar team took the family history seriously. That is the practical content of this topic — risk recognised before the knife, and multimodal treatment after it.
How the exam frames it
The guaranteed short note is keloid versus hypertrophic scar — candidates are expected to contrast onset, margin, natural course, sites and treatment in a structured comparison, and to name dark-skin susceptibility with the classical sites. The viva follows with management of a keloid: steroid first, excision never alone, adjuvants named. The Indian examination angle is real-world: India's skin-type distribution makes this a clinic everyday topic, and examiners frequently frame the objective question around the earlobe keloid after piercing. The dental bridge cuts both ways — intraoral mucosa's immunity to keloids (attributed to its distinct wound-healing milieu) is a favourite MCQ fact, while extraoral facial and neck incisions in susceptible patients demand the preventive checklist.
Frequently asked questions
What is the fundamental difference between a keloid and a hypertrophic scar?
A keloid extends beyond the original wound margins, persists and may continue growing; a hypertrophic scar remains within the wound boundaries and usually regresses within 12-18 months.
Why are keloids more common in Indians?
Dark skin carries a markedly higher genetic susceptibility, with familial clustering — melanocyte-cytokine interactions are implicated, and the sternum, earlobes and deltoids of young dark-skinned individuals are the classical sites.
What is the first-line treatment for a keloid?
Intralesional corticosteroid injection — triamcinolone acetonide 10-40 mg/mL every 4-6 weeks — commonly combined with silicone gel sheeting or pressure therapy.
Why is surgical excision alone discouraged for keloids?
Recurrence rates exceed half when keloids are excised without adjuvants, frequently returning larger; excision is combined with intralesional steroids, pressure, or early low-dose radiotherapy.
Do oral mucosal wounds form keloids?
Almost never — intraoral mucosa heals with minimal fibrous overgrowth, a contrast exploited whenever generous intraoral incisions are made despite the constant trauma of chewing.