LONDON – A rare and dangerous reaction to a range of common medicines including antibiotics and anticonvulsants may be caused by a severe immune response to reactivated herpes virus, scientists said on Wednesday. Researchers said their findings suggest that if doctors were to test for the herpes virus in patients suffering the drug reaction, they might be able to find ways to treat it and possibly stop it becoming more severe, or even fatal. The results should also help scientists find out what makes some people susceptible to the reaction, which is known as Drug Reaction with Eosinophilia and Systemic...