A herpes rash is a symptomatic outbreak stemming from a herpes simplex virus infection. Though the typical symptom of a herpes simplex infection is an outbreak of blisters, it is possible for a rash to appear instead. A herpes rash outbreak is often reddish in color, and is spread across a small area of the body where herpes simplex infection took place. A herpes rash outbreak can potentially appear at any time. A herpes rash will eventually clear on its own, but will clear more quickly when effective treatment is used. An untreated herpes rash will often clear within two weeks; when treatment is used, a herpes rash can clear within days. When any symptoms of a herpes simplex infection are present, whether it be a rash or blistering, herpes simplex is at its most contagious.