Two diseases of the cranial region with similar key symptoms — typical facial pain and epilepsy are analyzed. The objects of the study are the International Classification of Headache of the 3rd revision, 2018, fragments of which are facial pain, and the International Classification of Epilepsy and Epileptic Seizures, 2017. The key characteristic of both diseases is paroxysmality, that is, manifestations of the main signs of the disease in the form of seizures. The basic indicators of the disease, which are used in classifications, are similar in both cases — the origin (etiology) and the essence of seizures. However, the approaches here are different and even multidirectional. In the International Classification of Headaches, there is a clear desire to preserve the concept of «idiopathic» in the sections of paroxysmal facial pain for cases whose origin is unknown. On the contrary, in the International Classification of Epilepsy and Epileptic Seizures, the use of this term is extremely limited: it is replaced by the term «genetic» for forms of epilepsy, where it is proven, and «unknown etiology», previously «cryptogenic», facial pain and the International Classification of epilepsy and epileptic seizures: in the first case, changes in form, in the second in the content. Another object for analysis is ambiguous terminology. The analysis of paroxysms in two different diseases with paroxysmal symptoms — facial pain and epileptic seizures — reveals the divergence of their assessment according to the criteria of origin — idiopathic, genetic and unknown etiology (cryptogenic), as well as terminology of form and content.