ABSTRACT
This chapter deals with the common forms of ocular surface allergies, affecting the conjunctiva and cornea. The conjunctiva is usually the primary tissue affected, with the cornea suffering secondary effects that can be sight threatening. Allergic conjunctivitis is extremely common; it is estimated that 15–20% of the adult population will have at least one episode of symptomatic allergic conjunctivitis per year. Some forms are highly seasonal, related to pollen release by plants or dust and mites. The diagnosis of allergic conjunctivitis is clinical. Itching is the characteristic and most prominent symptom, and is directly related to mast cell degranulation and histamine release. Infectious forms of conjunctivitis and dry eye are the main differential diagnoses. Allergic rhinitis is often associated with tearing, photophobia and some redness of the eyes. Itching is usually absent. Treatment of the rhinitis is generally successful in resolving the ocular symptoms, which may have proved refractory to the standard topical ocular medications.
