The paper presents the case report of a patient diagnosed with borderline personality disorder, treated with carbamazepine. During the treatment symptoms of the infection of upper respiratory tract appeared, which evolved to allergic symptoms and then to morbilli-like and mumps-like symptoms. The patient was hospitalized due to this disorder for two weeks, in the beginning on an isolation ward and then was diagnosed and treated on a dermatological ward. The diagnosis of the disorder was doubtful due to polymorphic symptoms and their evolution. Detailed course of the disease, diagnostic process and laboratory results were presented in the case report. The authors also attempt to classify these symptoms and to analyse the relationship between the observed symptoms and drugs used during the treatment.