Pitfall: pemphigus herpeticatus should not be confounded with resistant pemphigus vulgaris.

Human herpes simplex virus (HSV) infections are well-recognized complications of various dermatoses and have also been reported in both hereditary and acquired acantholytic diseases such as dyskeratosis follicularis (Darier's disease), familial benign chronic pemphigus (Hailey-Hailey disease) and pemphigus vulgaris, respectively. The possibility of HSV infection should be considered in pemphigus patients with lack of improvement under adequate immunosuppressive therapy. This has therapeutic implications, since antiviral treatment instantly clears the HSV-induced chronic erosions. Instead, augmentation or change of immune suppression for assumed refractory pemphigus will obviously not improve the condition. We suggest using the diagnostic term pemphigus herpeticatus to describe HSV-superinfected pemphigus, alluding to the pathophysiologic analogies with eczema herpeticatum.