A scar is an expected result of wound healing. However, in some individuals, and particularly
in burn victims, the wound healing processes may lead to a fibrotic hypertrophic scar,
which is raised, red, inflexible and responsible for serious functional and cosmetic
problems. It seems that a wide array of subsequent processes are involved in hypertrophic
scar formation, like an affected haemostasis, exaggerated inflammation, prolonged
reepithelialization, overabundant extracellular matrix production, augmented neovascularization,
atypical extracellular matrix remodeling and reduced apoptosis. Platelets, macrophages,
T-lymphocytes, mast cells, Langerhans cells and keratinocytes are directly and indirectly
involved in the activation of fibroblasts, which in turn produce excess extracellular
matrix. Following the chronology of normal wound healing, we unravel, clarify and
reorganize the complex molecular and cellular key processes that may be responsible
for hypertrophic scars. It remains unclear whether these processes are a cause or
a consequence of unusual scar tissue formation, but raising evidence exists that immunological
responses early following wounding play an important role. Therefore, when developing
preventive treatment modalities, one should aim to put the early affected wound healing
processes back on track as quickly as possible.