Keloid scars, also known as keloids, are scars which grow out of control, growing large and protruding beyond the boundaries of the original wound. Keloids can appear at any stage during wound healing, and the reasons why they form are not fully understood. Treating keloids can be difficult, as they tend to recur. It is also difficult to prevent keloid scars, with such scars occurring on wounds which are perfectly cared for along with wounds which receive indifferent treatment or neglect.
These scars look very similar to hypertrophic scars, scars which become raised and thickened. The key difference between the two types of scar overgrowth is that keloid scars go beyond the original wound, while hypertrophic scars will spread to the margins of the wound and no further. Keloid scars can be rubbery to fibrous in texture, and white to reddish in color, depending on where they are and the types of collagen present in the scar tissue.
Keloids can grow quickly or slowly, and they can appear anywhere on the body, in people of any age, and in association with any wound, from an old pimple to the site of a surgery. Keloids can itch or sting with sharp pain, depending on the patient, and they may limit freedom of movement if they grow especially large. Keloid scars are generally treated as benign, because they will not cause further injury or damage, but people often want to get rid of them because they are unsightly, painful, or irritating.
Simple surgery for keloid scars is often ineffective because the overgrowth will return. Laser surgery, cryotherapy, and radiation are sometimes successful. Basic compression with a bandage at the wound site can also help to shrink a keloid. It is important to seek the advice of a doctor when trying to get rid of a keloid scar, as the scar can become infected, which can lead to complications for the patient.
These scars presumably form when the skin repairs itself after an injury and cell division goes wrong, promoting the uncontrolled growth of collagen and the development of a keloid. There is no way to prevent this from occurring, although proper wound care is generally a good idea. Keeping wound sites clean and dry will reduce the risk of infection, and may reduce the risk of keloid scarring. Compression bandages may also help, and they may be recommended after a surgeon performs a procedure which leaves a large wound behind.
Keloid scars are difficult to treat. There are various options. Reviews suggest that combinations of treatments are probably the most effective.
Intralesional steroid injections (with triamcinolone) are a mainstay of treatment and prevention - reviews suggest that it improves the majority of scars.
Injections are given every 2-6 weeks until improvement.
Side-effects: pigment changes, telangiectasia and subcutaneous atrophy (which may resolve).
Steroid-impregnated tape applied for 12 hours/day may flatten keloids.
These are used both for treatment and prevention, with minimal adverse effects, provided they are practical and acceptable to the patient. They must be used for 12-24 hours daily for several weeks or longer.
Silicone gel - this is applied as topical gel or a gel-impregnated sheet.
Compression earrings - are used after excision of earlobe keloids and give good rates of recurrence-free healing; they should be worn 24 hours/day.
Self-adhesive polyurethane scar reduction patches are also suggested.
Other pressure dressings may be used.
Surgical excision on its own has a very high recurrence rate and the recurring scar may even be larger than the original. Results can be improved by:
Meticulous surgical technique.
Additional treatments such as intralesional steroids, occlusive or pressure dressings or radiotherapy.
Radiotherapy is recommended, particularly post-surgery for the treatment of keloid scars. There have been concerns about its safety due to its carcinogenic properties but, providing surrounding tissues are protected, the risk is very low.
Cryotherapy has been used alone and combined with other treatments. Reported results vary:
Cryotherapy may stop early-stage keloids from growing.
It may be effective in combination with intralesional steroid.
Hypopigmentation is a side-effect.
Argon and carbon dioxide laser are probably not effective.
Pulsed dye lasers and Nd:YAG lasers are reported to give encouraging results, with few adverse effects. However, pulsed dye lasers are less effective on dark skin.
Laser treatment may reduce the redness of keloids without shrinking them.
Intralesional interferon alfa-2b has been shown to reduce keloid scars to a greater extent than steroids but is more expensive and causes more discomfort.
May be beneficial when used alone or in combination with other treatments.
Possible side-effects are pain, hypopigmentation and tissue sloughing.
This cytotoxic agent can be given locally as intralesional injections, and improved scars in one small study. Side-effects were hyperpigmentation and dermal atrophy.
Topical or intralesional retinoids have been used in clinical trials and produced some improvements.
Pharmacological treatment: various agents are being investigated.