Identified factors involved in pathophysiology of EM-lesions are perforin, thymus- and activation-regulated chemokine (TARC), IL-12 and soluble Fas-ligand among others [6,7].The present case was unique as it showed typical EM lesions due to HZ rather than with well-documented precipitating factors like herpes simplex, mycoplasma infection and drugs, including acyclovir. This evidence concerns the gene PRF1 and erythema multiforme.