Allergic conjunctivitis describes the eye's reaction to allergy-causing substances like pollen and dander. It usually includes redness, tearing, and itching.

Conjunctivitis - allergic

When your eyes are exposed to anything to which you are allergic, histamine is released and the blood vessels in the conjunctiva become swollen (the conjunctiva is the clear membrane that covers the "white" of the eye). Reddening of the eyes develops quickly and is accompanied by itching and tearing.

Allergies tend to run in families, although no obvious mode of inheritance is recognized. The incidence of allergy is difficult to determine, because many different conditions are often lumped under the term allergy. Keep in mind that rubbing the eyes makes the situation worse.

• May be seasonal
• Red eyes
• Dilated vessels in the conjunctiva (the clear membrane that covers the "white" of the eye)
• Intense itching or burning eyes
• Tearing (watery eyes)
• Puffy eyelids, especially in the morning
• Stringy eye discharge

Your doctor may look for the following:

• The presence of eosinophils (a type of white blood cell) in scrapings, secretions, or discharge
• A positive skin test for suspected allergens (see allergy testing)
• A pattern of small, raised bumps on the inside of the eyelids (papillary conjunctivitis)