Allergic conjunctivitis

Definition

Allergic conjunctivitis is inflammation of the tissue lining the eyelids (conjunctiva) due to a reaction from allergy-causing substances such as pollen and dander.

See also: Conjunctivitis

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

Symptoms may be seasonal and can include:

• Red eyes
• Dilated vessels in the clear tissue covering the white of the eye
• Intense itching or burning eyes
• Puffy eyelids, especially in the morning
• Tearing (watery eyes)
• Stringy eye discharge

Signs and tests

Your doctor may look for the following:

• Certain white blood cells, called eosinophils, in scrapings, secretions, or discharge
• Small, raised bumps on the inside of the eyelids (papillary conjunctivitis)
• Positive skin test for suspected allergens (See: Allergy testing)

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).

If home-care measures do not help, treatment by the health care provider may be necessary. This may include:

• Antihistamine or anti-inflammatory drops that are placed into the eye
• Mild eye steroid preparations applied directly on the surface of the eye (for severe reactions)
• Eye drops that prevent certain white blood cells called mast cells from releasing histamine; these drops are given in combination with antihistamines for moderate to severe reactions

Support Groups

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.

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References

Bielory L, Friedlaender MH. Allergic conjunctivitis. Immunol Allergy Clin North Am. 2008;28(1):43-58.