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Keloid and hypertrophic scarring

Also known as: keloids, hypertrophic scars, raised scars

Keloids and hypertrophic scars are raised forms of excessive scar tissue after skin injury or inflammation. Hypertrophic scars generally remain within the original wound; keloids extend beyond it. Assessment considers growth, symptoms, movement, appearance and the risk of recurrence when selecting care.

In plain English — These are raised scars that form when skin makes excessive scar tissue during healing. A hypertrophic scar usually stays within the original injury, while a keloid grows beyond it. Treatment can soften or flatten scars and help with itching, pain or restricted movement.

Evidence status

Moderate

Established conditions; variable treatment certainty. Clinical care aims to improve symptoms, function and appearance, often with more than one treatment. Controlled studies support some interventions, while comparative evidence for silicone sheeting and laser remains low or very low certainty. Scar type, body site and follow-up matter when interpreting outcomes.

What keloid and hypertrophic scarring are#

Both involve excessive raised scar tissue after injury or inflammation. A hypertrophic scar generally stays within the original wound and can become flatter with time. A keloid extends into surrounding skin and is more likely to persist. The distinction is useful, although some lesions have intermediate features and require experienced clinical assessment.[1, 3]

Keloids can follow acne, surgery, burns, cuts or piercing. They may develop after a delay and continue growing over months or years. Common sites include the chest, shoulders and ears. Firmness, itch, pain and restricted movement can matter as much as appearance. The subject here is raised scarring; acne scarring covers the assessment of depressed acne scars and mixed patterns.[2, 3]i[1, 2, 4]

Use of keloid and hypertrophic scarring in aesthetic practice#

Recognition helps practitioners support an appropriate referral and avoid treating every raised mark as a routine textural concern. Record the original injury, when thickening began, whether the lesion has extended, previous treatment and the person’s history of abnormal scars. Agree whether the main concern is discomfort, movement, appearance or a combination.[2, 3, 4]i

Support can include suitable skin care, sun protection, camouflage when wanted, and help with following a clinician’s scar plan. Early acne care is relevant when new inflammatory lesions are creating more scars. A history of keloids also changes the discussion about elective tattoos and piercings.[1, 2, 4]

Contraindications and cautions#

Previous abnormal scarring warrants individual risk assessment before an elective skin-injuring procedure. It is a history to discuss, not a risk that can be cleared simply from skin colour or a reassuring photograph. Keloids are more frequent in some populations, including people of South Asian, Chinese, African Caribbean and Black African backgrounds, but population associations do not determine an individual’s diagnosis.[2, 3]i[2, 3, 7]i

Pregnancy, breastfeeding, active infection, relevant medicines and systemic conditions can affect suitability for medical scar treatments. The prescribing or treating clinician should make those decisions. Silicone sheets are for appropriately healed skin, not an open wound or a scab. A suspicious lesion should be diagnosed before any attempted scar treatment.[2, 3, 7]i[3, 4]

Clinical uses and the evidence behind them#

Conservative scar care

Silicone preparations and, in selected settings, pressure devices are used to support scar management. Their practical advantages include a non-operative approach and the possibility of integrating them with other care. Suitability and adherence depend on site, comfort and skin tolerance.[3, 4]

For hypertrophic scars, a 2021 Cochrane review included 13 trials and 468 people with scars after surgery, burns or other injury, followed for three to twelve months. One 34-person study suggested less pain with silicone sheets than no sheets: mean score difference −1.26 (95% CI −2.26 to −0.26), low-certainty evidence. Several appearance comparisons remained uncertain.[5] For keloids, the separate 2023 review found two small trials and very-low-certainty evidence, leaving effects on appearance and pain uncertain. These findings support a measured discussion of possible benefit rather than a guarantee.[6]

Intralesional medicines

Corticosteroid injections are an established medical treatment option; some plans use another medicine such as 5-fluorouracil (5-FU). A 2024 double-blind trial in Nepal enrolled 66 people with keloids or hypertrophic scars and had 59 completers. Eligibility was over age 15, and one lesion per person was selected, preferentially on the trunk or proximal limbs. At 12 weeks, triamcinolone plus 5-FU improved height and scar scores more than triamcinolone alone, with fewer recorded adverse effects. The authors reported no specific grant or conflicts. This short, mixed-scar trial did not assess recurrence.[7]

Laser, cryotherapy and specialist combined treatment

Specialist plans may use selected lasers to address scar characteristics or cryotherapy for suitable lesions. A 2022 Cochrane laser review found a possible benefit from 585-nm pulsed-dye laserversus no treatment: risk ratio for improvement 1.96 (95% CI 1.11–3.45; two trials, 60 scar segments, low certainty). Across the review’s 15 trials, follow-up ranged from 12 weeks to 12 months; other laser comparisons were too uncertain to establish an overall preferred approach.[8][3, 4]

Excision is another specialist option, particularly when a substantial lesion or functional problem requires it, but a keloid can recur after the new wound. It is therefore considered with a recurrence-prevention plan, which may involve medical treatment, pressure or selected postoperative radiotherapy. Radiotherapy requires specialist assessment of site, age and potential late harms; it is not routine salon or skincare treatment.[2, 3, 4]i

Selecting an assessment and management plan#

Assessment comes first. Document scar location, growth, surface condition, pain, itch, restriction of movement and previous response to treatment. A stable, comfortable scar and a growing, painful lesion crossing a joint pose different problems even if both are described as “raised”.[2, 3, 4]i

A plan should identify its goal, how progress will be judged and when it will be reviewed. Changes in comfort, pliability, height and daily function can be recorded alongside photographs and a scar score. The Vancouver Scar Scale and Patient and Observer Scar Assessment Scale are research and clinical assessment tools used in the retrieved trial, not substitutes for diagnosis.[2, 3, 4]i[7]

Choose supportive products or prescribed devices around the clinician’s plan and the person’s ability to use them comfortably. Scar care often lasts long enough that skin tolerance and practical usability matter.[3, 4]

Adverse effects and their management#

Adverse effects vary by treatment. Steroid injections can cause skin or fat atrophy, visible small vessels and pigment change. Cryotherapy can leave a lighter area and may produce a wound that heals slowly. Lasers can cause pain, colour changes or surface injury, with risks depending on the modality and settings. These possibilities belong in clinical consent and follow-up.[3, 4, 8]

Tape, occlusion and pressure materials can irritate the skin or become uncomfortable. New rash, skin breakdown or worsening pain should prompt review of the product or device and contact with the treating service. Warmth, swelling or pain with pus requires urgent medical assessment for possible infection.[1, 2, 3]

Referral and scope boundaries#

Growing, painful, itchy or movement-limiting scars warrant assessment by a GP or clinician experienced in scar management. Substantial psychological impact also deserves support, whether or not a procedure is chosen. Children, complex lesions and recurrent scars may require a specialist team.[1, 2, 3]

An atypical lesion needs diagnosis. The Japan Scar Workshop consensus notes that benign tumours and malignancies, including dermatofibrosarcoma protuberans, can resemble pathological scars; rapid growth is one reason a clinician may consider biopsy. Aesthetic practitioners should not assume that every firm nodule following a minor injury is a keloid.[3, 4]

Injections, surgery and radiotherapy described here are medical or specialist options, not instructions or a statement of practitioner entitlement. The Japanese consensus supplies clinical context, not a UK licensing rule.[3, 4]

Mechanism of action#

Raised scar formation involves persistent inflammatory activity and altered collagen deposition in the dermis. Mechanical tension can contribute to continued activity. The Japan Scar Workshop describes these processes as a model connecting tissue behaviour, lesion growth and treatment rationale, while acknowledging gaps in the underlying biology. See the wound-healing cascade for the wider repair process.[3]i

Treatment targets differ. Corticosteroids suppress inflammatory activity; 5-FU is an antimetabolite used to influence proliferating scar tissue. Silicone’s proposed benefit relates in part to surface hydration, while fixation and pressure address aspects of the scar’s mechanical environment. These rationales explain why treatments are considered; clinical outcomes still need to be assessed for the particular intervention and scar.[3]i

Commonly misstated claims#

Counting scars as participants

Claim heard:“The keloid silicone review studied 85 people.”

Literature finding: Its two trials included 36 people with 85 scars; several scars could come from the same person.[6]

Supported statement: Report people, lesions and analysed scar segments separately; they are not interchangeable sample sizes.

A response percentage presented as cure

Claim heard:“Steroid plus 5-FU cured 97% of keloids.”

Literature finding:In Acharya’s trial, 31 of 32 analysed combination-group participants met a threshold of at least 50% reduction in scar height at week 12. The study included both hypertrophic scars and keloids.[7]

Supported statement: That percentage describes a defined short-term response in a mixed population, not complete scar removal or a permanent keloid cure.

Treatment evidence transferred to prevention

Claim heard:“A trial treating existing scars proves that the same product prevents scars after every procedure.”

Literature finding: The silicone reviews cited here evaluated treatment of established hypertrophic scars or keloids, with specific comparators and follow-up. They did not estimate a universal preventive effect after fresh injury.[5, 6]i

Supported statement: Prevention of a new scar and treatment of an existing one require evidence matched to those different questions.

Areas of remaining uncertainty#

  • Long-term control: early flattening may not predict later behaviour. Agree a follow-up plan instead of judging success only at the end of a short treatment course.[7]
  • Best sequence: studies differ in scar type, site, maturity and combined treatments. A positive result does not identify one sequence for every person.[8][5]
  • Patient-important outcomes:comparative studies often report appearance more fully than daily function or wellbeing. Include the person’s symptoms and priorities when reviewing care.[1, 2, 4][6]

Frequently asked questions#

Can a scar become raised after a small injury?

Yes. Keloids can follow relatively minor skin injury, as well as surgery, burns or acne. The history of previous scars is useful when assessing risk.[2, 3]i

Should a comfortable scar always be treated?

No. Assessment and the person’s priorities guide that decision. Treatment goals may concern comfort, movement or appearance, and those goals differ between people.[1, 2, 4]

Is itch a useful reason to seek help?

Yes. Itch and pain are recognised symptoms and valid treatment concerns, even when the scar’s appearance is not the main issue.[1, 2, 4]

Can camouflage be part of care?

Yes. It is an optional way of managing appearance and can sit alongside, or apart from, medical treatment. It does not replace assessment of a changing lesion.[3, 4]

References#

Each source is graded by evidence tier. Tier 4 material (manufacturer documents, expert consensus, practitioner experience) is useful for protocol and context, and is never presented as equivalent to independent clinical evidence.

  1. NHS. Scars. Reviewed 18 September 2023. Accessed 16 September 2026.Tier 4Supports: Clinical appearance and natural history of hypertrophic versus keloid scars; discomfort, restricted movement, psychological support and infection-related urgent assessment.Funding / interest: NHS patient information; no product sponsor stated. Not a formal evidence-graded clinical guideline.
  2. NHS. Keloid scars. Reviewed 7 February 2023. Accessed 16 September 2026.Tier 4Supports: Growth beyond the original injury, common sites, symptoms, prior-keloid and population risk, early assessment and avoiding elective tattoos/piercings when susceptible.Funding / interest: NHS patient information; no product sponsor stated. Displayed review-due date had passed; not treated as a newly updated guideline.
  3. Ogawa R, Akita S, Akaishi S, et al. Diagnosis and Treatment of Keloids and Hypertrophic Scars—Japan Scar Workshop Consensus Document 2018. Burns & Trauma. 2019;7:39. doi:10.1186/s41038-019-0175-y. PMID:31890718.Tier 4Supports: Diagnosis and intermediate appearances, tumour differential, inflammatory/tension model, symptoms, treatment rationale, complications and specialist combined management. Japanese consensus, not UK prescribing or licensing policy.Funding / interest: Article states funding not applicable and no competing interests. Consensus incorporates expert experience and sparse evidence for some recommendations; not a systematic review or RCT.
  4. American Academy of Dermatology. Keloid scars: diagnosis and treatment. Updated 26 January 2023. Accessed 16 September 2026.Tier 4Supports: Clinical diagnosis, individual goals, medical treatment families, silicone use on healed skin, treatment-related pigment effects and specialist recurrence prevention.Funding / interest: AAD patient information; no page-specific product sponsor declared on the retrieved page. Broader AAD corporate relationships are not treated as a page-specific sponsorship finding.
  5. Jiang Q, Chen J, Tian F, Liu Z. Silicone gel sheeting for treating hypertrophic scars. Cochrane Database of Systematic Reviews. 2021;(9):CD013357. doi:10.1002/14651858.CD013357.pub2. PMID:34564840.Tier 1Supports: Thirteen trials, 468 participants, follow-up three to twelve months; low/very-low certainty, possible pain benefit and uncertain appearance differences for several comparisons. Searches through April 2021.Funding / interest: Review-specific funding and conflicts were not available in the personally retrieved Cochrane complete abstract/summary and official core record; no independence claim made.
  6. Tian F, Jiang Q, Chen J, Liu Z. Silicone gel sheeting for treating keloid scars. Cochrane Database of Systematic Reviews. 2023;(1):CD013878. doi:10.1002/14651858.CD013878.pub2. PMID:36594476.Tier 1Supports: Two trials, 36 people and 85 scars, three- and four-and-a-half-month follow-up; effects on appearance and pain uncertain, very-low-certainty evidence. Searches through December 2021.Funding / interest: Review-specific support/conflicts not established from the personally retrieved Cochrane complete abstract/summary and official core record; unknown rather than presumed absent.
  7. Acharya R, Agrawal S, Khadka DK, Pant AR. Efficacy and safety of intralesional triamcinolone acetonide alone and its combination with 5-fluorouracil in keloids and hypertrophic scars: randomized, parallel group, and double blinded trial. Skin Health and Disease. 2024;4(5):e450. doi:10.1002/ski2.450. PMID:39355745.Tier 2Supports: Single-centre Nepal trial, 66 enrolled and 59 completed, mixed raised-scar types, eligibility over age 15, one lesion per person preferentially on trunk/proximal extremity, 12-week endpoint. Combination improved measured outcomes more than triamcinolone alone; recurrence not assessed.Funding / interest: Authors report no specific public, commercial or not-for-profit grant and declare no conflicts of interest. Full primary text retrieved.
  8. Leszczynski R, da Silva CA, Pinto ACPN, Kuczynski U, da Silva EM. Laser therapy for treating hypertrophic and keloid scars. Cochrane Database of Systematic Reviews. 2022;(9):CD011642. doi:10.1002/14651858.CD011642.pub2. PMID:36161591.Tier 1Supports: Fifteen trials, 604 children/adults, 12-week to 12-month follow-up; low-certainty PDL comparison and very-low-certainty evidence for several other comparisons. Searches through March 2021; scar segments distinguished from people.Funding / interest: Review-specific funding and conflicts not available in personally retrieved Cochrane complete abstract/summary and official core record.