Merck Manual

Please confirm that you are a health care professional

honeypot link

Allergic Conjunctivitis

(Atopic Conjunctivitis; Atopic Keratoconjunctivitis; Hay Fever Conjunctivitis; Perennial Allergic Conjunctivitis; Seasonal Allergic Conjunctivitis; Vernal Keratoconjunctivitis)

By

Melvin I. Roat

, MD, FACS, Sidney Kimmel Medical College at Thomas Jefferson University

Last full review/revision Apr 2021
Click here for Patient Education
Topic Resources

Allergic conjunctivitis is an acute, intermittent, or chronic conjunctival inflammation usually caused by airborne allergens. Symptoms include itching, lacrimation, discharge, and conjunctival hyperemia. Diagnosis is clinical. Treatment is with topical antihistamines and mast cell stabilizers.

Etiology of Allergic Conjunctivitis

Seasonal allergic conjunctivitis (hay fever conjunctivitis) is caused by airborne mold spores or pollen of trees, grasses, or weeds. It tends to peak during the spring, late summer, or early fall and disappear during the winter months—corresponding to the life cycle of the causative plant.

Perennial allergic conjunctivitis (atopic conjunctivitis, atopic keratoconjunctivitis) is caused by dust mites, animal dander, and other nonseasonal allergens. These allergens, particularly those in the home, tend to cause symptoms year-round.

Vernal keratoconjunctivitis is a more severe type of conjunctivitis most likely allergic in origin. It is most common among males aged 5 to 20 years who also have eczema Atopic Dermatitis (Eczema) Atopic dermatitis is a chronic relapsing inflammatory skin disorder with a complex pathogenesis involving genetic susceptibility, immunologic and epidermal barrier dysfunction, and environmental... read more Atopic Dermatitis (Eczema) , asthma Asthma Asthma is a disease of diffuse airway inflammation caused by a variety of triggering stimuli resulting in partially or completely reversible bronchoconstriction. Symptoms and signs include dyspnea... read more , or seasonal allergies. Vernal keratoconjunctivitis typically reappears each spring and subsides in the fall and winter. Many children outgrow the condition by early adulthood.

Symptoms and Signs of Allergic Conjunctivitis

General

Patients with allergic conjunctivitis report having

  • Bilateral mild to intense ocular itching

  • Conjunctival hyperemia

  • Photosensitivity (photophobia in severe cases)

  • Eyelid edema

  • Watery or stringy discharge

Findings characteristically include conjunctival edema and hyperemia and a discharge. The bulbar conjunctiva may appear translucent, bluish, and thickened. Chemosis and a characteristic dermatoblepharitis with hyperemia, edema and lichenification of the medial upper first and then lower eyelid, are common. Chronic itching can lead to chronic eyelid rubbing, periocular hyperpigmentation, and dermatoblepharitis.

Seasonal and perennial conjunctivitis

In people with seasonal and perennial conjunctivitis, fine papillae on the upper tarsal conjunctiva give it a velvety appearance. In more severe forms, larger tarsal conjunctival papillae, conjunctival scarring, corneal neovascularization, and corneal scarring with variable loss of visual acuity can occur.

Vernal keratoconjunctivitis

Usually, the palpebral conjunctiva of the upper eyelid is involved, but the bulbar conjunctiva is sometimes affected. In the palpebral form, square, hard, flattened, closely packed, pale pink to grayish cobblestone papillae are present in the upper tarsal conjunctiva. The uninvolved bulbar conjunctiva is milky white. In the bulbar (limbal) form, the circumcorneal conjunctiva becomes hypertrophied and grayish. Discharge may be tenacious and mucoid, containing numerous eosinophils.

In 3 to 11% of patients, a corneal ulcer Corneal Ulcer A corneal ulcer is a corneal epithelial defect with underlying inflammation usually due to invasion by bacteria, fungi, viruses, or Acanthamoeba. It can be initiated by mechanical trauma or... read more Corneal Ulcer develops, causing pain and increased photophobia. Other corneal changes (eg, central plaques) and white limbal deposits of eosinophils (Horner-Trantas dots) may be seen.

Diagnosis of Allergic Conjunctivitis

Treatment of Allergic Conjunctivitis

  • Symptomatic measures

  • Topical antihistamines, nonsteroidal anti-inflammatory drugs, mast cell stabilizers, or a combination

  • Topical corticosteroids or cyclosporine for recalcitrant cases

  • Sometimes, oral antihistamines

Avoidance of known allergens and use of cold compresses and tear supplements can reduce symptoms of allergic conjunctivitis; antigen desensitization is occasionally helpful. Topical over-the-counter antihistamines (eg, ketotifen) are useful for mild cases. If these drugs are insufficient, topical prescription antihistamines (eg, olopatadine, bepotastine, azelastine, cetirizine), mast cell stabilizers (eg, nedocromil, cromolyn), or nonsteroidal anti-inflammatory drugs (eg, ketorolac) can be used separately or in combination. Topical corticosteroids (eg, loteprednol, fluorometholone 0.1%, prednisolone acetate 0.12% to 1% drops 3 times a day) can be useful in recalcitrant cases or when quick relief of symptoms is important. Because topical corticosteroids can lead to a flare-up of latent ocular herpes simplex virus infections Herpes Simplex Keratitis Herpes simplex keratitis is corneal infection with herpes simplex virus. It may involve the iris. Symptoms and signs include foreign body sensation, lacrimation, photophobia, and conjunctival... read more Herpes Simplex Keratitis , possibly leading to corneal ulceration and perforation and, with long-term use, to glaucoma Overview of Glaucoma Glaucomas are a group of eye disorders characterized by progressive optic nerve damage in which an important part is a relative increase in intraocular pressure (IOP) that can lead to irreversible... read more and possibly cataracts Cataract A cataract is a congenital or degenerative opacity of the lens. The main symptom is gradual, painless vision blurring. Diagnosis is by ophthalmoscopy and slit-lamp examination. Treatment is... read more Cataract , their use should be initiated and monitored by an ophthalmologist. Topical cyclosporine drops may be helpful. Corticosteroid or tacrolimus ointment applied to the skin is very effective in the treatment of eyelid atopic dermatitis Atopic Dermatitis (Eczema) Atopic dermatitis is a chronic relapsing inflammatory skin disorder with a complex pathogenesis involving genetic susceptibility, immunologic and epidermal barrier dysfunction, and environmental... read more Atopic Dermatitis (Eczema) . Oral antihistamines (eg, fexofenadine, cetirizine, or hydroxyzine) can be helpful, especially when patients experience other allergic symptoms (eg, rhinorrhea).

Seasonal allergic conjunctivitis is less likely to require multiple drugs or intermittent topical corticosteroids.

Key Points

  • Allergic conjunctivitis is usually caused by airborne allergens and can be seasonal or perennial.

  • Symptoms tend to include itching, eyelid edema, stringy or watery discharge, and sometimes a history of seasonal recurrence.

  • Diagnosis is usually clinical.

  • Treatment includes tear supplements and topical drugs (usually antihistamines, vasoconstrictors, nonsteroidal anti-inflammatory drugs, mast cell stabilizers, or a combination).

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read
Test your knowledge
Refractive Surgery
Which of the following possible complications of refractive surgery is most likely to result in loss of best-corrected acuity?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP