Hypertrophic scars sometimes are difficult to distinguish from keloid
scars histologically and biochemically, but unlike keloids, hypertropic scars remain confined to the injury site and often mature
and flatten out over time. Hypertrophic scars are more common in people with lighter complexions. The most common locations include
chest, back, shoulders, earlobes, the lower face and, in general, any pressure- or movement-dependent areas of your body. Scars from
the healing of deep second degree burns and those formed at the fringe of a skin graft are prone to hypertrophy.
Hypertrophic scars are thick and raised and often darker in color than surrounding skin. Hypertrophic scar
formation is not a part of normal wound healing and can develop over time. These kinds of scars are a problem in patients with a
genetic predisposition (tendency) to scarring, and in deep wounds that require a long time to heal.
Both hypertrophic and keloid scars produce larger amounts of collagen than normal scars. Typically the
hypertrophic type of scar exhibits declining collagen synthesis after about six months. On the other hand, hypertrophic scars contain
nearly twice as much glycosaminoglycan as normal scars. This and enhanced synthetic and enzymatic activity of the hypertrophic
scar result in significant alterations in the matrix which affects the mechanical properties of the scars, including decreased
extensibility that makes them feel firm.
Pressure therapy is frequently used in the treatment of hypertrophic scars.