Hypertrophic scars and keloids

Last updated: November 15, 2023

Summarytoggle arrow icon

Hypertrophic scars and keloids are cutaneous conditions caused by a disruption of wound healing in response to a dermal injury. Hyperproliferation, which manifests as thick, raised scar tissue, is caused by an increase in TGF-β expression, fibroblast proliferation, and collagen deposition. Hypertrophic scars typically form after a burn injury or surgical incision, whereas keloids have a genetic component and can occur after minor trauma. Diagnosis for children and adults is typically clinical; keloid scars have an irregular edge that extends beyond the original margins of the scar, whereas the borders of hypertrophic scars remain within the original margins. Skin biopsy is rarely necessary but can be considered if skin malignancy is suspected. Management is similar for children and adults, and prevention strategies are the most important method to reduce hyperproliferation. Although benign, both types of scars can be a cosmetic concern or cause debilitating contractures. Multiple treatment options are available and usually scars respond best to a combination of treatments. Hypertrophic scars generally regress within one year and respond well to treatment, whereas keloids commonly recur even with treatment.

Definitiontoggle arrow icon

  • Hypertrophic scar [1]
    • An overgrowth of tissue that is thickened and raised within the boundaries of the original margins of a scar
    • Usually regresses spontaneously
  • Keloid [1]
    • An overgrowth of tissue that is thickened and raised with an irregular border that extends beyond the original margins of a scar
    • Does not spontaneously regress and may recur if surgically excised

Epidemiologytoggle arrow icon

  • Age: can occur at any age but more commonly occurs between ∼10–30 years of age [2][3]
  • Genetic factors [1][2]
    • Hypertrophic scars: A genetic component has not been observed.
    • Keloids: Most common in black, Asian, and Hispanic individuals. [3]

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Risk factorstoggle arrow icon

Hypertrophic scars are typically caused by burns and surgical incisions. [6]

Pathophysiologytoggle arrow icon

Clinical featurestoggle arrow icon

Clinical features of hypertrophic scars and keloids [1][2][3]
Hypertrophic scar Keloids
  • ≤ 3 months [4]
  • ≥ 3 months
  • Nonspecific but commonly affects: [6]
  • Can occur anywhere; most commonly seen on: [2]
    • Earlobes
    • Face (especially cheeks)
    • Upper extremities
    • Chest
    • Pubic area
  • Within the boundaries of the original scar [4][5][6]
  • Irregular [6]
  • Expands beyond the boundaries of the original scar [5]
  • Raised [5]
  • Red or flesh-colored [9]
  • Thickened
  • Firm [4]
  • Keloids: possible claw-like appearance
Clinical course
  • Spontaneous regression [3]
  • Recurrence is infrequent.
  • No spontaneous regression [3]
  • Recurrence is frequent after surgical excision.

Keloid scars extended beyond the wound edges, while hypertrophic scars remain within. [5]

Diagnosticstoggle arrow icon

  • Diagnosis is usually clinical, based on appearance and history of trauma or surgery. [3][10]
  • Skin biopsy can be performed if the diagnosis is uncertain or if there is suspicion of malignancy. [6][11]

Avoid skin biopsy of keloids unless malignancy is suspected, as the procedure can promote hyperproliferative scarring. [2]

Managementtoggle arrow icon

Approach [5]

  • Monitor wounds to facilitate early identification and management.
  • If hypertrophic or keloid scars develop in the first 6 months:
    • Encourage patients to regularly moisturize.
    • Apply silicone cream or dressings.
    • Use pressure treatments.
    • Widespread hypertrophic scars or growing keloid
      • Refer to a specialist.
      • Start intralesional corticosteroid injections.
  • For scars present > 6 months after injury:
    • Utilize all of the aforementioned treatments.
    • Refer to a specialist for consideration of additional therapies and/or surgical excision.

Refer patients with contractures for surgical excision, regardless of how long the scar has been present. [11]

First-line treatments

The following treatments may be used alone or in combination; the choice of treatment will depend on the age of the scar, location, and patient preference.

Silicone treatments [12]

Pressure therapy (compression therapy)

  • Indications
  • Options: Referral for custom fitting may be required. [4]
    • Pressure clips for the earlobes
    • Compressive masks for the face
    • Garments or bandages (e.g., spandex, elastic adhesive) for the body
  • Instructions for use: Wear 23 hours a day with a pressure of 24–30 mm Hg. [1][13]
  • Contraindications: severe peripheral arterial disease, decompensated heart failure [14]

Adherence to pressure therapy may be low because of discomfort, frequency of application, and cost. [1]

Intralesional corticosteroids

Surgical excision

Additional therapies [1][5]

A specialist may combine any of the therapies below with first-line therapies to improve outcomes.

Avoid radiation therapy in children < 12 years of age and during pregnancy because of its potential carcinogenic effects. [4]

Prognosistoggle arrow icon

  • Hypertrophic scars
    • Frequently regress within 1 year without treatment [3]
    • Typically respond well to treatment, if needed [1]
  • Keloids
    • Respond better to early treatment [1][3]
    • Flatten after treatment with intralesional corticosteroid injections in up to 50% of cases [1]
    • Nearly always recur after surgical excision unless other therapies are also administered [1][2]

Preventiontoggle arrow icon

General principles [5]

  • Prevention strategies are the most effective way to avoid hyperproliferative scarring.
  • All individuals: Basic preventive measures should be used during the first 6 weeks after injury.
  • For individuals with risk factors for hypertrophic and keloid scars, the following precautions are recommended:
    • Avoidance of elective surgeries and piercings
    • Frequent wound assessments for early identification

Prevention strategies [1][3][5]

All wounds

High-risk wounds for hyperproliferative scarring

Referencestoggle arrow icon

  1. Monstrey S, Middelkoop E, Vranckx JJ, et al. Updated Scar Management Practical Guidelines: Non-invasive and invasive measures. J Plast Reconstr Aesthet Surg. 2014; 67 (8): p.1017-1025.doi: 10.1016/j.bjps.2014.04.011 . | Open in Read by QxMD
  2. Elsaie ML. Update on management of keloid and hypertrophic scars: A systemic review. J Cosmet Dermatol. 2021; 20 (9): p.2729-2738.doi: 10.1111/jocd.14310 . | Open in Read by QxMD
  3. O’Brien L, Jones DJ. Silicone gel sheeting for preventing and treating hypertrophic and keloid scars. Cochrane Database Syst Rev. 2013.doi: 10.1002/14651858.cd003826.pub3 . | Open in Read by QxMD
  4. Grabowski G, Pacana MJ, Chen E. Keloid and Hypertrophic Scar Formation, Prevention, and Management. J Am Acad Orthop Surg. 2020; 28 (10): p.e408-e414.doi: 10.5435/jaaos-d-19-00690 . | Open in Read by QxMD
  5. Juckett G, Hartman-Adams H. Management of keloids and hypertrophic scars. Am Fam Physician. 2009; 80 (3): p.253-60.
  6. ISBI Practice Guidelines Committee, Ahuja RB, Gibran N, et al. ISBI Practice Guidelines for Burn Care. Burns. 2016; 42 (5): p.953-1021.doi: 10.1016/j.burns.2016.05.013 . | Open in Read by QxMD
  7. Liu A, Moy RL, Ozog DM. Current Methods Employed in the Prevention and Minimization of Surgical Scars. Dermatol Surg. 2011; 37 (12): p.1740-1746.doi: 10.1111/j.1524-4725.2011.02166.x . | Open in Read by QxMD
  8. Ogawa R. The Most Current Algorithms for the Treatment and Prevention of Hypertrophic Scars and Keloids: A 2020 Update of the Algorithms Published 10 Years Ago. Plast Reconstr Surg. 2021; 149 (1): p.79e-94e.doi: 10.1097/prs.0000000000008667 . | Open in Read by QxMD
  9. Tian F, Jiang Q, Chen J, Liu Z. Silicone gel sheeting for treating keloid scars. Cochrane Database Syst Rev. 2023; 2023 (1).doi: 10.1002/14651858.cd013878.pub2 . | Open in Read by QxMD
  10. Ogawa R. Textbook on Scar Management. Springer International Publishing ; 2020
  11. Berman B, Maderal A, Raphael B. Keloids and Hypertrophic Scars: Pathophysiology, Classification, and Treatment. Dermatol Surg. 2017; 43 (1): p.S3-S18.doi: 10.1097/dss.0000000000000819 . | Open in Read by QxMD
  12. Harris IM, Lee KC, Deeks JJ, Moore DJ, Moiemen NS, Dretzke J. Pressure-garment therapy for preventing hypertrophic scarring after burn injury. Cochrane Database Syst Rev. 2020.doi: 10.1002/14651858.cd013530 . | Open in Read by QxMD
  13. Cameron MH. Physical Agents in Rehabilitation. Elsevier Health Sciences ; 2021
  14. Mayeaux EJ. The Essential Guide to Primary Care Procedures. LWW ; 2015
  15. O’Boyle CP, Shayan-Arani H, Hamada MW. Intralesional cryotherapy for hypertrophic scars and keloids: a review. Scars Burn Heal. 2017; 3: p.205951311770216.doi: 10.1177/2059513117702162 . | Open in Read by QxMD
  16. Schwaiger H, Reinholz M, Poetschke J, Ruzicka T, Gauglitz G. Evaluating the Therapeutic Success of Keloids Treated With Cryotherapy and Intralesional Corticosteroids Using Noninvasive Objective Measures. Dermatol Surg. 2018; 44 (5): p.635-644.doi: 10.1097/dss.0000000000001427 . | Open in Read by QxMD
  17. Goutos I, Ogawa R. Steroid tape: A promising adjunct to scar management. Scars Burn Heal. 2017; 3: p.205951311769093.doi: 10.1177/2059513117690937 . | Open in Read by QxMD
  18. Nestor MS, Berman B, Goldberg D, et al. Consensus Guidelines on the Use of Superficial Radiation Therapy for Treating Nonmelanoma Skin Cancers and Keloids. J Clin Aesthet Dermatol. 2019; 12 (2): p.12-18.
  19. Morelli Coppola M, Salzillo R, Segreto F, Persichetti P. Triamcinolone acetonide intralesional injection for the treatment of keloid scars: patient selection and perspectives. Clin Cosmet Investig Dermatol. 2018; Volume 11: p.387-396.doi: 10.2147/ccid.s133672 . | Open in Read by QxMD
  20. Del Toro D, Dedhia R, Tollefson TT. Advances in scar management. Curr Opin Otolaryngol Head Neck Surg. 2016; 24 (4): p.322-329.doi: 10.1097/moo.0000000000000268 . | Open in Read by QxMD
  21. Finnerty CC, Jeschke MG, Branski LK, Barret JP, Dziewulski P, Herndon DN. Hypertrophic scarring: the greatest unmet challenge after burn injury. Lancet. 2016; 388 (10052): p.1427-1436.doi: 10.1016/s0140-6736(16)31406-4 . | Open in Read by QxMD

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