A 49-year-old man suffered from Hailey-Hailey disease for several years. The patient presented with an acute exacerbation of the disease, which did not respond to oral treatment with high doses of glucocorticosteroids. A skin biopsy was taken and the histological examination indicated a viral infection. Herpes simplex virus was confirmed by electron microscopy (negative staining) and polymerase chain reaction (PCR). The PCR presents a sensitive and effective molecular-biological method for the diagnosis of viral infections.