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[Conditions](https://durgical.com/en/conditions/) · [Dermatology](https://durgical.com/en/conditions/)

# Keloid and hypertrophic scar

Keloids and hypertrophic scars are raised scars from excess healing tissue. Keloids spread beyond the wound; hypertrophic scars stay within it.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Skin](https://durgical.com/en/anatomy/skin/)
- [Auricle](https://durgical.com/en/anatomy/auricle/)
- [Mandible](https://durgical.com/en/anatomy/mandible/)

## Why it happens

- [Fibrosis in organs: TGF-β and the myofibroblast](https://durgical.com/en/general-pathology/fibrosis-in-organs-tgf-and-the-myofibroblast/)
- [Granulation tissue and scar formation](https://durgical.com/en/general-pathology/granulation-tissue-and-scar-formation/)
- [Abnormal repair: chronic wounds, hypertrophic scar, keloid, contracture](https://durgical.com/en/general-pathology/abnormal-repair-chronic-wounds-hypertrophic-scar-keloid-contracture/)
- [Healing of skin wounds: first and second intention](https://durgical.com/en/general-pathology/healing-of-skin-wounds-first-and-second-intention/)
- [Thermal injury: burns, hyperthermia and hypothermia](https://durgical.com/en/general-pathology/thermal-injury-burns-hyperthermia-and-hypothermia/)
- [Collagen synthesis](https://durgical.com/en/biochemistry/topics/collagen-synthesis/)

## Show 2 more

- [Extracellular matrix: collagen types, elastin, ground substance](https://durgical.com/en/histology/extracellular-matrix-collagen-types-elastin-ground-substance/)
- [Wound healing: phases and scar](https://durgical.com/en/histology/wound-healing-phases-and-scar/)

## What it is

Abnormal fibroproliferative healing responses with excess collagen. A hypertrophic scar is raised but stays within the borders of the original wound and often flattens over time. A keloid extends beyond the wound margins into normal [skin](https://durgical.com/en/anatomy/skin/), rarely regresses and frequently recurs after excision.

## Who gets it

Keloids are much more common in people with darker skin (African and mixed ancestry), a large group in Colombia's Pacific and Caribbean regions, and peak between puberty and age 30. Hypertrophic scars are common after burns and surgery at any age. A family history is frequent in keloids.

## Causes

- Skin injury of any kind: surgery, burns, lacerations, piercings, acne, vaccination, insect bites
- Genetic predisposition (familial keloids)
- Wound tension, infection and delayed healing
- Hormonal influences (keloids can grow in puberty and pregnancy)

## Risk factors

- Darker skin and family history of keloids
- Age 10–30 years
- High-tension sites: [chest](https://durgical.com/en/anatomy/region/chest/) ([sternum](https://durgical.com/en/anatomy/sternum/)), shoulders, upper back, earlobes, jawline
- Burns, infected or slow-healing wounds
- Ear piercing and severe acne

## Pathophysiology

After injury, healing normally moves from inflammation to proliferation and then remodelling. In these scars, fibroblasts stay overactive, driven by growth factors such as TGF-beta and by mechanical tension, and produce excess collagen. Hypertrophic scars contain organised type III collagen nodules with myofibroblasts; keloids contain thick, disorganised hyalinised type I and III collagen bundles and invade surrounding dermis.

## Classification

- Hypertrophic scar: confined to the wound, appears within weeks, may regress, linked to tension and burns
- Keloid: extends beyond the wound, appears months later, does not regress, high recurrence, linked to genetics and skin type

## Symptoms and signs

- Firm, raised, shiny scar, pink-red early and later skin-coloured or darker
- Keloids: claw-like extension beyond the original wound, dumbbell shape on earlobes
- Itch and tenderness or pain, sometimes intense
- Contracture and reduced movement when hypertrophic scars cross joints (especially after burns)
- Cosmetic and emotional distress

## Red flags

- Rapid growth, ulceration or bleeding in a scar (rule out malignancy, such as Marjolin ulcer or dermatofibrosarcoma)
- A 'keloid' appearing without any prior injury
- Scar contracture limiting function of a joint, eyelid or mouth

## Diagnosis

**Clinical**
Clinical, based on history of injury, timing, and whether the scar stays within or extends beyond the wound margins.

**Tests**
Biopsy only for atypical lesions (rapid growth, no history of trauma, ulceration) to exclude tumours; biopsy can itself trigger more keloid.

**Imaging**
Not needed. Photographs and scar scales are used to follow response.

## Differential diagnosis

- Dermatofibroma and dermatofibrosarcoma protuberans
- Foreign-body granuloma (for example after piercing)
- Lobomycosis (keloid-like nodules in Amazon regions)
- Sarcoidosis in scars
- Squamous cell carcinoma arising in a scar

## Goal of treatment

Prevent abnormal scarring in at-risk patients, and flatten, soften and relieve itch and pain in established scars while avoiding recurrence; combined treatments work better than one alone.

## Treatment

**Conservative**
Silicone gel or sheets and pressure therapy (garments, pressure earrings), started soon after the wound closes; first-line for prevention and for early scars.

**Medical**
Intralesional corticosteroids are first-line for established keloids, often combined with 5-fluorouracil; topical corticosteroids or antihistamines for itch.

**Procedure**
Cryotherapy, pulsed-dye or fractional lasers and, in specialised centres, radiotherapy immediately after keloid excision.

**Surgical**
Excision of keloids only combined with adjuvant therapy (corticosteroid injections, pressure or radiotherapy), because excision alone recurs in most cases; scar revision and release of contractures for hypertrophic burn scars.

## Complications

- Recurrence after treatment, often larger
- Chronic itch and pain
- Contractures and functional limitation
- Skin atrophy and hypopigmentation from corticosteroid injections
- Psychological distress

## Prognosis

Hypertrophic scars often improve over 12–24 months. Keloids are persistent and recur often, but combination treatment can control symptoms and reduce size.

## Prevention

- Avoid unnecessary procedures and piercings in predisposed people
- Close wounds with low tension and treat acne and wound infections early
- Use silicone and pressure early on wounds at risk

## Test yourself

Think of the answer, then tap the question to see it.

## What is the key clinical difference between a keloid and a hypertrophic scar?

A keloid extends beyond the original wound margins and rarely regresses; a hypertrophic scar stays within them and often improves.

## What is the first-line treatment for an established keloid?

Intralesional corticosteroid injections, often combined with other measures.

## Why is excision alone a poor treatment for keloids?

Recurrence after simple excision is very high, so surgery must be combined with adjuvant therapy.

## Which are three high-risk sites for keloids?

Earlobes, the sternum/chest, shoulders and upper back, and the jawline.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/keloid-and-hypertrophic-scar/)

## Related conditions

- [Acne vulgaris](https://durgical.com/en/conditions/acne-vulgaris/)
- [Hidradenitis suppurativa](https://durgical.com/en/conditions/hidradenitis-suppurativa/)
- [Abscess, furuncle and carbuncle](https://durgical.com/en/conditions/abscess-furuncle-and-carbuncle/)
- [Cutaneous squamous cell carcinoma](https://durgical.com/en/conditions/cutaneous-squamous-cell-carcinoma/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Keloids](https://medlineplus.gov/ency/article/000849.htm) (MedlinePlus, US National Library of Medicine, 2026).

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Source: https://durgical.com/en/conditions/keloid-and-hypertrophic-scar/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/keloid-and-hypertrophic-scar/