Genetics
A common cause of cold sores lies in a person’s genetics. Approximately 85 percent of the population are infected with the herpes virus, but only about a quarter get frequent cold sores. The reason why cold sores appear more frequently in some people was not known, but new research suggests that some people may have a genetic predisposition to frequent, severe cold sores.
Researchers at the University of Edinburgh have found that those affected with cold sores have a mutation in a gene, making their immune system incapable of suppressing the virus sufficiently.
