RESUMEN
The pterygial tissue excised from 30 eyes of 30 patients with primary pterygium were subjected to immunohistopathological staining in order to identify the type of antibodies present within such growth. Immunoglobulin E was found in 27 specimens [90%], while immunoglobulin G was found in 23 specimens [76.6%]. From the above findings, it could be assumed that pterygium formation may be a type 1 hypersensitivity reaction. Despite the commonality of pterygium, little is truly known about its etiology. Many theories have been proposed to explain the cause of pterygium, however, most of these theories cannot be reconciled with known facts. It was found that chronic inflammation in the form of conjunctivitis or episcleritis initiates the process. An allergic theory was proposed by Hilgers, while Taylor specifically incriminated exposure to ultraviolet B as the causative factor