Allergic conjunctivitis, or an allergy that manifests in the eyes, occurs when the immune system overreacts to a foreign substance. This reaction causes a release of the chemical histamine, which causes the symptoms of allergic reactions such as eye swelling, itching, redness. There are different types of allergic conjunctivitis, with different causes and different treatments.
Atopic Keratoconjunctivitis
Atopic keratoconjunctivitis occurs in people with a family history of allergies such as asthma, hay fever and sensitive skin, as well as the skin condition eczema. This condition is not seasonal like vernal keratoconjunctivitis. Symptoms include eye itching, tearing and a mucus discharge. The cornea can be more involved in this type of keratoconjunctivitis, with epithelial defects, corneal ulcers and scarring. According to the University of Michigan Kellogg Eye Center, treatments include mast cell stabilizers such as cromolyn sodium and antihistamines as preventative measures; for active disease, steroids may be used. If this condition is not treated appropriately, it can cause a significant loss of vision.
Vernal Keratoconjunctivitis
Vernal keratoconjunctivitis is a relatively rare condition that occurs in warm and dry climates, typically between April and August. The patient develops intense eye itching and a thick, stringy discharge, as noted by the University of Michigan Kellogg Eye Center. In this allergy, the conjunctiva of the upper eyelid develops large bumps, and the rest of the conjunctiva can become swollen. Treatment includes mast cell stabilizers; in severe cases, corticosteroids might be used.
Seasonal Allergic Conjunctivitis
Seasonal allergic conjunctivitis, the most common type of allergic conjunctivitis, is also the mildest form of all conjunctivitis conditions. This type of allergy is worse during the spring and fall, the prime hay fever and ragweed allergy seasons. Symptoms include itching, tearing and redness, though the cornea is not involved in this type of allergy. According to the website Handbook of Ocular Disease Management, the most effective treatment reducing contact with the offending substance, or allergen, and topical and oral antihistamines are helpful for alleviating symptoms. Mast cell stabilizers and medications that combine the actions of antihistamines and mast cell stabilizers are used as well.
Giant Papillary Conjunctivitis
Giant papillary conjunctivitis is seen in patients who wear contact lenses or who have a foreign substance in the eye, like a prosthesis. As noted by the Handbook of Ocular Disease Management website, the allergic reaction may be caused by deposits on the lenses. The patient may notice difficulty wearing the contact lenses and a foreign body sensation in the eyes. The underside of the upper eyelid develops bumps called papillae. Treatment for this condition includes extra lubrication such as artificial tears, and antihistamines and mast cell stabilizers. Changing the type of contact lens worn may also help.
References
- University of Michigan Kellogg Eye Center: Atopic Keratoconjunctivitis
- University of Michigan Kellogg Eye Center: Vernal Keratoconjunctivitis
- Handbook of Ocular Disease Management: Allergic Conjunctivitis
- Handbook of Ocular Disease Management: Giant Papillary Conjunctivitis
- Indiana University School of Optometry: Types of Allergic Conjunctivitis
