Genetic testing for prevention of severe drug-induced skin rash.

Background: Drug-induced skin reactions present with a range of clinical symptoms, from mild maculopapular skin rashes to potentially fatal blistering skin rashes - such as Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) - which may result in death. Milder reactions may be troublesome and lead to low drug compliance. The pathogenesis of these drug reactions is not yet fully understood; however, there is evidence that pretreatment genetic testing may help to predict and prevent these reactions in some cases.