Allergic conjunctivitis occurs when the conjunctiva becomes swollen or inflamed due to a reaction to pollen, dander, mold, or other allergy-causing substances. The conjunctiva is a clear layer of tissue lining the eyelids and covering the white of the eye.
When your eyes are exposed to allergy-causing substances, a substance called histamine is released by your body. The blood vessels in the conjunctiva become swollen. The eyes can become red, itchy, and teary very quickly.
The pollens that cause symptoms vary from person to person and from area to area. Tiny, hard-to-see pollens that may cause hay fever include grasses, ragweed and trees.
Your symptoms may be worse when there is more pollen in the air. Higher levels of pollen are more likely on hot, dry, windy days. On cool, damp, rainy days most pollen is washed to the ground.
Allergies tend to run in families. It is hard to know exactly how many people have allergies. Many conditions are often lumped under the term "allergy" even when they might not truly be an allergy.
Exams and Tests
Your health care provider may look for the following:
- Certain white blood cells, called eosinophils
- Small, raised bumps on the inside of the eyelids (papillary conjunctivitis)
- Positive skin test for suspected allergens on allergy tests
The best treatment is to avoid what causes your allergy symptoms as much as possible. Common triggers to avoid include dust, mold and pollen.
Some things you can do to ease symptoms are:
- Use lubricating eye drops.
- Apply cool compresses to the eyes.
- Take over-the-counter oral antihistamines. These medicines can offer more relief, but they can sometimes make your eyes dry.
If home-care does not help, you may need to see a health care provider for treatments such as:
- Antihistamine or anti-inflammatory drops
Mild eye steroid drops can be prescribed for more severe reactions. You may also use eye drops that prevent a type of white blood cell called mast cells from releasing histamine. These drops are given along with antihistamines. These medicines work best if you take them before you come in contact with the allergen.
Symptoms often go away with treatment. However, they can persist if you continue to be exposed to the allergen.
There are no serious complications.
When to Contact a Medical Professional
Call your health care provider if you have symptoms of allergic conjunctivitis that do not respond to self-care steps and over-the-counter treatment.
Conjunctivitis - allergic seasonal/perennial; Atopic keratoconjunctivitis
Bielory L, Friedlaender MH. Allergic conjunctivitis. Immunol Allergy Clin North Am. 2008;28(1):43-58. PMID: 18282545 www.ncbi.nlm.nih.gov/pubmed/18282545.
Haq SM, Singh S, Song BJ, Trocme SD. Ocular allergic disorders. In: Tasman W, Jaeger EA, eds. Foundations of Clinical Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013: vol 2, chap 30.
Stock EL, Meisler DM. Vernal keratoconjunctivitis. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:vol 4;chap 9.
Update Date 9/2/2014
Updated by: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.