A scar is the product of your genetic code – the DNA in cells – and its interaction with the environment. Sometimes it is difficult to understand why a particular scar has become problematic. For fibroproliferative types such as hypertrophic and keloid scars, the influence of our genes may be predictable. Our genes in childhood are better at priming our inflammatory and immune systems when we are injured and as such, a skin injury is more likely to produce an angry scar compared to later in life. Also, as a result of their genes some races are more likely to have fibroblast cells which produce excessive amounts of connective tissue like collagen – the key component of a scar.
In terms of environmental factors which may make a scar worse, most of them are linked to increasing the duration or intensity of inflammation. For example, if a burn injury is slow to heal or a wound from an operation gets infected, the increased time period over which the area is attempting to heal makes it more likely that in the long run, more fibrous connective tissue will accumulate in a scar. Excessive pulling or tension across a healing wound is increasingly implicated as a factor which may increase inflammation and scar formation.
An environmental factor that clearly has an effect on the appearance on skin scarring is sunlight exposure. Scars can be more sensitive to ultraviolet light for more than a year. An inability to respond to ‘photodamage’ may lead to worsening inflammation and altered pigmentation. The latter phenomenon may make a scar more conspicuous relative to its surroundings. Generally, covering scars or protection with sunscreen products are recommended for what can be a prolonged period of time.
Some areas of the body are more prone to severe scars. These areas include the ears, the top of the shoulder and the area in front of the breastbone (sternum). There are lots of theories as to why this may be. Some people have suggested that it is due to the genes at these sites which have a more angry response to injury. Others have proposed that the fibroblast cells are pulled in multiple different directions by the tension in these areas and in turn this leads them to become more active.