Urticaria, often known as hives, is a common cutaneous illness that affects between 15% and 25% of the population at some point in their lives. The purpose of this research was to compare the serum Claudin-3 levels of patients with chronic urticaria to those of healthy controls and to determine whether or not there was a correlation between the two. Methods: Fifty patients with chronic urticaria were recruited from the Dermatology outpatient clinic at Benha University Hospital, and thirty healthy persons were recruited to serve as a control group and were matched with cases for age and sex. The Benha Faculty of Medicine's Research Ethics Committee on Research Involving Human Subjects gave its stamp of approval for the study to proceed. All contributors voluntarily provided informed consent. Claudin 3 serum levels were found to be significantly higher in the sick group compared to the control group. Increases in claudin 3 levels are positively correlated with severity. Claudin 3 levels were the only ones investigated as a potential predictor of CU severity. Claudin 3 has a highly correlated favourable relationship with UAS. Claudin 3 levels were found to be considerably greater in CU patients compared to healthy controls. The presence and quantity of Claudin 3 are both risk factors for developing CU and indicators of the severity of the disease.