Hypertrophic scars are raised, darkened, rigid, nodular lesions which only occur in humans.
In addition to cosmetic concern, these scars may cause pain, itch, contractures, and other functional impairments.
They are commonly caused by burns, wound closure with excess tension, wound infection, delayed wound healing, hypoxia (deprivation of adequate oxygen supply), or other skin injury. Many times they develop after surgery.
Read this post for more info on treatment of scars after surgery.
In contrast to keloids, which are a type of hypertropic scarring, their growth is limited to the boundaries of the original wound. Keloids however extend beyond the original wound bed.
They are the result of a disproportionate response to wound healing. They represent an over-production of collagen created during the healing process.
The newly created collagen is arranged in a disorganized pattern which causes this type of scar tissue to be hardened, elevated, and poorly extensible.
Hypertrophic scars are also characterized by an excessively increased amount of blood vessels which causes redness. Also, increased blood supply, natural part of the healing process makes these scars darker than surrounding skin.
“Abnormal scars can cause unpleasant symptoms and can be aesthetically distressing, disfiguring and psychosocially and functionally disabling.” (1)
It may take up to two months for a hypertrophic scar to come to presence and its cosmetic appearance may worsen over the next six months. They generally grow quickly during the first 6 months while regression takes place the next 12 to 18 months.
Factors such as the location on the body, thickness of the skin, (de)hydration, sun exposure, mechanical stress, and nutritional deprivation impact development of hypertrophic scars.
Some individuals are more susceptible to these scars then others. They generally occur more often in young and dark skinned people.
Treatments include topical medications, steroid injections, cryosurgery, and laser therapy.
Steroid injections are a common type of treatment for these scars. They work by inhibiting fibroblast growth, reducing the amount of collagen present in the scar tissue. Downside are detrimental side effects such as hypopigmentation (whitening of the tissue due to a decrease in skin pigmentation), atrophy (depressed tissue), and telangiectasias (red marks as a result of small, widened blood vessels).
Cryotherapy is often used in conjunction with steroid injections. This therapy may also be used independently but has shown to be more effective when used in combination with steroid injections.
Silicone sheeting has lots of clinical data showing efficacy. This type of treatment provides non-invasive, pain-free therapy with mild to no side effects. (some people develop a mild rash upon using silicone sheets)
Effective home remedies are limited but have become increasingly popular because of their non-invasiveness, ease of use, and relatively low cost. And here some more info on treatment of hypertrophic scars.
1. Bayat A et al. BMJ 2003;326:88-92