Allergic conjunctivitis Allergic conjunctivitis Allergic conjunctivitis is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness (mainly due to vasodilation of the peripheral small blood vessels), edema (swelling) of the conjunctiva, itching, and increased lacrimation (production of tears). If this is combined with rhinitis, the condition is termed allergic rhinoconjunctivitis. The symptoms are due to release of histamine and other active substances by mast cells, which stimulate dilation of blood vessels, irritate nerve endings, and increase secretion of tears.
Allergic rhinitis positive. The symptoms of allergies resemble those of the common cold; however, they often last for more than two weeks and typically do not include a fever. Exposure to animals in early life might reduce the risk of developing allergies to them later. A number of medications may improve symptoms including nasal steroids, antihistamines such as diphenhydramine, cromolyn sodium, and leukotriene receptor antagonists such as montelukast. Medications are, however, not sufficient or are associated with side effects in many people. Exposing people to larger and larger amounts of allergen, known as allergen immunotherapy, is often effective. The allergen may be