- Abnormally large overgrowths of fibrous tissue (scar) occurring as a result of trauma or irritation that do not subside with time
- System(s) affected: Skin/Exocrine
- Predominant age: 10–30 years
- Higher incidence during puberty and pregnancy
- Predominant sex: Female > Male
- However, mean age between the two sexes is almost identical, with females getting first keloid at 22.3 years of age and males developing first keloid at 22.8 years.
- 4–16% of the black and Hispanic populations
- Also a higher incidence in the Asian population
- Data from the UK demonstrated that <1% of Caucasians had keloids.
- Family history of keloids
- Dark skin pigment
- Certain locations on the body (e.g., deltoids, chest, neck, earlobes)
- More common in blacks and Asians (5–15×) than in whites; in all races, more darkly pigmented individuals are at higher risk.
- Both autosomal dominant and autosomal recessive familial inheritance have been reported.
- Primary prevention: Avoid elective surgery, body piercing, or tattooing in high-risk patients.
- Wounds should be kept clean to prevent infection.
- When feasible, laparoscopic approaches are preferred in keloid formers.
- Compressive pressure dressings may be useful in high-risk (e.g., burn) patients. Local steroid injection postoperatively in high-risk patients is also effective.
- Wounds: Traumatic, surgical, body piercing (foreign-body reaction)
- Wound infection
- Burn injury
- Other injuries:
- Insect bite
- Folliculitis barbae and nuchae
- Vaccination (especially bacille Calmette-Guérin)
- Rarely occur in places on body lacking sebaceous glands; thus sebaceous glands, and the body’s reaction to this sebum, are hypothesized to be a etiologic factor in keloid development. Moreover, humans are the only mammals with sebaceous glands and the only mammals affected by keloids.
- Increased ratio of type I to type III collagen
- Increased density and proliferation rate of fibroblasts
- Pruritus (occasional)
- May be asymptomatic
- Grow beyond the border of the original wound
- Firm, smooth, elevated scar with sharply demarcated borders
- Initially may be pale or mildly erythematous
- Older lesion hypopigmented or hyperpigmented
- Scar extends beyond margins of the initial wound.
- Over period of years, keloids may continue to grow and may develop clawlike projections.
- Keloids occur more frequently on the chest, shoulders, upper back, back of the neck, and earlobes.
Diagnostic Tests & Interpretation
Biopsy only if unable to differentiate from carcinoma or infectious disease because a biopsy may increase the keloid’s size. Use a 2-mm punch biopsy to minimize trauma.
Histology shows whorl-like arrangements of hyalinized collagen bundles, with pressure thinning of papillary dermis and minimal elastic tissue.
- Hypertrophic scar (usually regresses spontaneously, does not cross wound margins, and rarely more than 1 cm in thickness and width)
- Infiltrating basal cell carcinoma
- Sclerosing metastatic malignancies
- Desmoplastic melanoma
- Leprosy (nodular LL type)
- Other fibronodular skin diseases (e.g., neurofibromatosis, post-kala-azar dermal leishmaniasis)
- Given the high recurrence rates and significant expense associated with treatment, prevention of keloids should take priority. Avoidance of known risk factors such as piercings, tattoos, and elective surgery is highly recommended in people with either a family or personal history of keloids.
- A recent meta-analysis of 70 studies has shown that all the currently accepted treatment options have fairly comparable efficacy, with a mean improvement of 60% (1). Also of note is that keloids do not regress spontaneously.
- Treatment options should be based on the type of keloid. Characteristics to take into consideration: (1) presence/absence of scar contractures; (2) size; and (3) number of keloids.
- Small, single keloids can be treated more aggressively.
- Large or multiple keloids are typically more complicated to treat and should be evaluated on an individual basis (2).
- Triamcinolone (Kenalog) suspension 10 mg/mL (3)[A]:
- Most commonly used treatment option. Likely more effective if combined with cryotherapy, pulsed dye laser or 5-fluorouricil. No difference when combined with excision versus monotherapy (2).
- 72% showed symptomatic improvement in 1 trial (3).
- Use 27- to 30-gauge needle and a TB syringe (total dose 20–30 mg triamcinolone); may inject 3 lesions at a time using 10 mg/lesion.
- Advance the needle while injecting to distribute medication evenly.
- Early keloids are more responsive to this therapy than are older lesions.
- Reinject every 4 weeks until keloid shrinks to near skin surface.
- If no response to 10 mg/mL triamcinolone suspension, may try 40 mg/mL suspension
- May mix dilute triamcinolone (5–10 mg/mL) with local anesthetic for excision of keloids; postoperative steroid injections at 2–4 weeks and then monthly for 6 months help to prevent recurrences.
- Contraindications: Active skin infection at injection site
- Systemic absorption with reversible adrenal suppression, hyperglycemia
- Local effects: Skin atrophy, ulceration, depigmentation, telangiectasias
- Both types of side effects are more common with 40 mg/mL triamcinolone suspension.
- Significant possible interactions: Rare interactions (only with very large doses of corticosteroids and systemic absorption)
- Silica gel sheeting: 1st-line prophylaxis after surgical procedure or keloid excision (3)[A],(4)[C]
- Patient compliance limits effectiveness.
- Sheets are cut to fit and must be worn for at least 12 hours and, optimally, 24 hours/day.
- Unclear whether benefit is from silicone or occlusive effect
- Adverse effects are generally from irritation: pruritus, rash, erosion, and maceration. There is complete resolution within a few days of removal.
- Cryotherapy is likely to be more useful in early, smaller lesions. It is not recommended for larger areas owing to pain and decreased skin pigmentation (2).
- Verapamil locally may be helpful as an adjuvant following excision and topical silicone (3)[C].
- Interferon-α2b may be helpful after excision (3)[C].
- Topical imiquimod (Aldara) may be helpful after excision.
- Intralesional 5-fluorouracil (3)[C]: One study showed a 92% reduction in lesion size when combined with triamcinolone and excision (5).
- Intralesional bleomycin (3)[C]
- Radiation therapy has greater success rates when used in combination with surgical excision. There are some concerns about precipitating malignant lesions with radiation; however, a direct correlation has not been made (2).
Radiation therapy, 5-fluorouracil, and bleomycin are unsafe in pregnancy.
- Appropriate health care: Outpatient
- Intralesional corticosteroid injection causes atrophy, telangiectasia, and pigment changes in half of patients but is the most successful therapy (3)[A].
- Pressure bandages must maintain 24 mm Hg and should be worn for 6–12 months (3)[C]. Bandages should not be removed for >30 min/day.
- Pressure clips (Zimmer splints) are useful for earlobes (6)[C]. Designer splints look like fashion earrings.
- Cryotherapy may be useful for small keloids (e.g., acne scars) (3)[C].
- Use 10- to 30-second freeze–thaw cycles every month; may cause permanent hypopigmentation.
- Topical agents: No evidence to support efficacy of retinoic acid, vitamin E, allantoin, or onion extract (3); some evidence for imiquimod.
Issues for Referral
When intralesional steroids fail, referral to dermatologist or plastic surgeon may be indicated.
- Local radiotherapy may be effective after excision but carries a small risk of carcinogenesis (7)[B].
- Physical therapy useful if contractures associated
Complementary and Alternative Medicine
None proven (3)
- Surgery: High recurrence rate (45–100%) if used alone; therefore, is used only for the debulking of large keloids or if a lesion is unresponsive to steroid injections or other therapy; combine with preoperative steroid injection and possibly other modalities (3). Debulking just enough for symptomatic improvement is recommended (2).
- Pulsed-dye laser surgery: No definitive evidence of efficacy or advantage over other methods; therefore, use only if other methods fail, and then use in conjunction with them (3)[C]; some promise is seen in combination with triamcinolone and 5-fluorouracil (4)[C].
Monthly visits for up to 1 year for evaluation and possible steroid reinjections
No special diet
- Stress the possibility of recurrence despite appropriate treatment.
- May require many months of treatment with combined modalities
- Prevention: In those with risk factors or previous keloids, caution against activities or procedures that may entail dermal disruption, and suggest early treatment of any such events.
When treatment is successful, lesions gradually diminish over 6–18 months with therapy, leaving a flat, shiny scar. While keloids can improve with treatment, cure is unlikely.
Skin atrophy, ulceration, depigmentation, and telangiectasias can occur as a result of local steroid injections.
1. Leventhal D, Furr M, Reiter D. Treatment of keloids and hypertrophic scars: a meta-analysis and review of the literature. Arch Facial Plast Surg. 2006;8:362–8.
2. Ogawa R et al. The most current algorithms for the treatment and prevention of hypertrophic scars and keloids. Plast Reconstr Surg. 2010;125:557–68.
3. Mustoe TA, Cooter RD, Gold MH, et al. International clinical recommendations on scar management. Plast Reconstr Surg. 2002;110:560–71.
4. Asilian A, Darougheh A, Shariati F. New combination of triamcinolone, 5-Fluorouracil, and pulsed-dye laser for treatment of keloid and hypertrophic scars. Dermatol Surg. 2006;32:907–15.
5. Davison SP, Dayan JH, Clemens MW, Sonni S, Wang A, Crane A. Efficacy of intralesional 5-fluorouracil and triamcinolone in the treatment of keloids. Aesthet Surg J. 2009;29(1):40–6.
6. Russell R, Horlock N, Gault D. Zimmer splintage: a simple effective treatment for keloids following ear-piercing. Br J Plast Surg. 2001;54:509–10.
7. Ogawa R, Mitsuhashi K, Hyakusoku H, et al. Postoperative electron-beam irradiation therapy for keloids and hypertrophic scars: retrospective study of 147 cases followed for more than 18 months. Plast Reconstr Surg. 2003;111:547–53; discussion 554–5.
Seifert O, Mrowietz U. Keloid scarring: bench and bedside. Arch Dermatol Res. 2009.
See Also (Topic, Algorithm, Electronic Media Element)
Bites; Burns; Warts; Leprosy
701.4 Keloid scar
33659008 keloid scar (disorder)
- The most successful treatment of hypertrophic scar or keloid is achieved while the scar is still immature, but the overlying epithelium is intact, although this is not as yet confirmed in the literature.
- Keloids extend beyond the margins of the original wound and do not regress with time; this is a way of differentiating from hypertrophic scars. Treatment is similar, but keloids are much more likely to recur.
- Closing wounds with a minimum of suture tension, avoiding midsternal incisions and crossing joint lines, and injecting steroids into the incision postoperatively reduce the chance of keloids forming following unavoidable surgery.