Infections with herpes simplex virus (HSV) type 1 are highly prevalent in populations worldwide and frequently associated with chronic exacerbations. Sixty percent to 90% of the world’s population are seropositive, and 20% to 40% of infected subjects have recurrent symptoms.1 The primary infection, which is often asymptomatic and affects mainly the orofacial region, leads to a latent viral infection of the sensory neurons. Reactivation is trig- gered by endogenous and exogenous stimuli, such as emotional stress, UV light exposure, immunosuppression, or mechanical in- juries, and can occur with or without symptoms. Herpes labialis, the most common form of symptomatic HSV-1 recurrence, is usu- ally mild and self-limited but can cause considerable distress in subjects with frequent exacerbations. Eczema herpeticum, the symptomatic infection of larger skin areas usually affected by atopic dermatitis; herpes simplex keratitis; and herpes encephali-tis are rare but severe complications of HSV-1 infection.2,3