Background. One of the autoimmune diseases is pemphigus, a chronic malignantly occurring autoimmune dermatosis accompanied by the development of blisters on the skin and mucous membranes. Isolated lesions of the SOPR occur in 10–20% of cases, complicating differential diagnosis. Numerous studies have proven the role of herpes virus infection as an aggravating factor in the course of true acantholytic pemphigus. The aim of the study was to determine the features of the clinical course of vulgar pemphigus against the background of reactivation of chronic EBV infection (glossitis caused by EBV). The clinical case of a patient with a diagnosis of “Vulgar pemphigus. Glossitis caused by the Epstein-Barr virus”. The anamnesis of the disease was carefully collected, a clinical and laboratory examination was performed with a cytological examination of a smear taken from a LITTER, a general blood test with an expanded leukocyte formula, C-reactive protein. In order to diagnose the viral load, PCR diagnostics was performed on the DNA of the herpes virus 1, 2, 4, 5 types in saliva, on the DNA of EBV in the blood, quantitatively. Specific antibodies of Ig classes M and G to EBV were determined by the ELISA method. Results. Due to the lifelong persistence of EBV in the structures of the oral cavity, its reactivation leads not only to chronic pastoral infection and the local development of the corresponding glossitis, but also, first of all, to a decrease in the level of local immunity. This fact aggravates the course of pemphigus, shortens the period of absence of relapse. The appointment of antiviral therapy at the first visit allowed to stabilize the symptoms caused by EBV, which led to positive dynamics in the course of pemphigus against the background of average dosages of prednisone in a shorter time. Conclusions. With clinical and laboratory confirmation of chronic EBV infection (glossitis caused by EBV), it is recommended to include antiviral and immunocorrective drugs, systemically and topically, in the complex treatment of pemphigus erythematosus.