Scars: how pharmacists can help
A scar is a visible result of wound healing. When a wound heals, scar tissue (fibrous collagen) is formed. This can occur externally and internally. Minor injuries that only involve the epithelium (eg, superficial scratches) are unlikely to cause scarring but any injury that involves the dermis and deeper tissues may leave a scar. Causes include surgical operations, trauma, burns and diseases affecting the skin (eg, acne or chickenpox).
Scars are aesthetically and functionally inferior to the tissue that they replace. Some experts suggest that wound healing has been optimised for speed of healing under dirty conditions and that scarring is the price we pay for this survival advantage.
For most people, scars are not a problem but some scars can be disfiguring, painful or functionally disabling. A number of treatments have been used and products marketed for scar reduction. Pharmacists may be asked for advice about these as well as on scar prevention after an injury.
Wound healing can be divided into three stages: inflammatory, proliferative and maturative. Immediately after an injury, the coagulation cascade is activated. A fibrin clot is formed and platelets are trapped. Platelets release platelet-derived growth factor (PDGF) that attracts neutrophils. Neutrophils digest bacteria and activate fibroblasts (cells that generate collagen) and keratinocytes (skin cells that will proliferate to form new epithelium). Lymphocytes and monocytes are also attracted to the wound and the scene is set for the proliferative phase.
During the proliferative phase there is active repair of tissues. Cytokines (including PGDF, transforming growth factor-b (TGF-b) and vascular endothelial growth factor [VEGF]) control the laying down of collagen and the formation of new blood vessels. This is also often described as the granulation phase because the base of a healing wound has a granular appearance. In addition to granulation, the wound begins to contract. As this phase progresses and the wound fills up from the base with regenerating tissue, a recognisable skin surface begins to form (epithelialisation). Finally, in response to an unknown signal, fibroblast activity and vascular proliferation cease and this brings the proliferative phase to an end.
For a normal scar, the maturation phase involves gradual fading and flattening of the scar tissue. This phase usually takes between 12 and 18 months.
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Citation: The Pharmaceutical Journal URI: 10997337
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