Health Encyclopedia

Allergic conjunctivitis

Definition

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

Alternative Names

Conjunctivitis - allergic

Causes, incidence, and risk factors

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.

Symptoms

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

Signs and tests

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)

Treatment

The best treatment is avoiding exposure to the cause or allergen; unfortunately, this is not often practical. Discomfort can be relieved by applying cool compresses to the eyes or taking antihistamines by mouth (many of these are available over-the-counter).

For episodes that do not respond to the treatments above, treatment by the health care provider may be necessary. This may include:

Giving ophthalmic (eye) antihistamine or anti-inflammatory drops
Giving mild ophthalmic steroid preparations, directly on the surface of the eye, for severe reactions
Giving eye drops of medicine that stop mast cells (special white blood cells) from releasing histamine; these drops are given in combination with antihistamines for moderate to severe reactions

Expectations (prognosis)

Treatment usually relieves the symptoms. However, the condition tends to recur if exposure to the offending agent continues.

Complications

There are no serious complications; persistent discomfort is common.

Calling your health care provider

Call for an appointment with your health care provider if you experience allergic conjunctivitis and it is unresponsive to over-the-counter treatment.

Prevention

Prevention of allergic conjunctivitis is best accomplished by avoiding the allergen, if it is known. In many cases, however, this is impossible since the allergy-causing agents are everywhere nearly all the time.

Review Date:9/1/2006
Reviewed By:Manju Subramanian, MD, Assistant Professor in Ophthalmology, Vitreoretinal Disease and Surgery, Boston University Eye Associates, Boston, MA. Review provided by VeriMed Healthcare Network.

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