Allergic conjunctivitis is an allergic reaction of the eye to an allergen such as pollen, mold or dander. It involves an inflammation of the clear membrane that covers the white of the eye and can result in itching, burning, and redness in the eye. Swollen eyelids, watery eyes and eye discharge also are symptoms of allergic conjunctivitis.

There are several forms of allergic conjunctivitis:

• Seasonal allergic conjunctivitis (SAC). Flares up on a seasonal basis and is frequently associated with allergic rhinitis.
  
  
• Perennial allergic conjunctivitis (PAC). Symptoms manifest themselves year-round.
  
  
• Vernal conjunctivitis. More common in the spring and fall, afflicts more males than females, and can lead to vision loss. Vernal conjunctivitis exists in both allergic and non-allergic forms.
  
  
• Atopic keratoconjunctivitis. A type of allergic conjunctivitis that is associated with atopic dermatitis of the eyelids and face.

Pollen is the primary allergen that triggers allergic conjunctivitis. Tree and grass pollens tend to trigger the condition in spring and early summer, while weed pollens tend to be the main culprit in the summer and early fall. Allergic conjunctivitis also can result from contact with dust and fungus spores, or from coming into contact with certain animal and vegetable proteins.

Frequently, those who suffer from allergic conjunctivitis also have a family history of conditions such as allergic rhinitis, asthma or eczema.

Allergic conjunctivitis is just one form of the disease. There also are other forms of conjunctivitis, such as bacterial conjunctivitis, which is caused by bacteria, and viral conjunctivitis, which is caused by viruses.