Cat eye sores are also known as erythema multiforme, which is an alias for erythema multiforme, or a figurative term. It is also called cat eye sore because the appearance of erythema multiforme is a target type of damage, similar to the symptoms of a cat’s eye. The formation of erythema multiforme is mostly related to the abnormal immune function of the body and the occurrence of this kind of allergic reaction, or the formation of vasculitis on the skin surface. In addition to infectious factors, there are also allergic factors, as well as other factors including endocrine dysfunction or abnormalities in the immune system that cause a skin condition.