Symptoms
Symptoms of allergic conjunctivitis include itching, red eyes, eye watering, a thin discharge, and sneezing. The conjunctiva may be swollen, making it appear glassy. The itching and red eyes are particularly characteristic of the disease.
Causes
The inflammation is often caused by a pollen allergy (hay fever). In this case, it is also called seasonal allergic conjunctivitis and allergic rhinoconjunctivitis. Depending on the season, the symptoms occur mainly in sunny and dry weather. Often – but not always – the nose is affected at the same time. The so-called perennial allergic conjunctivitis occurs throughout the year and is caused by dust mites, cats and other allergens. In this case, allergic rhinitis also often occurs at the same time. The deeper cause of symptoms is IgE-mediated release of inflammatory mediators, particularly histamine from mast cells and basophils. Histamine triggers vasodilatation, increases capillary permeability, and causes itching. Finally, many other allergens, such as cosmetics, medications and sun creams, can lead to allergic conjunctivitis. Other, rarer syndromes exist, such as vernal conjunctivitis (spring catarrh) or atopic conjunctivitis.
Diagnosis
Diagnosis is made by medical treatment. Similar ocular symptoms may be caused by other ocular diseases that must be excluded at diagnosis, such as other forms of conjunctivitis, dry eyes, and eyelid rim inflammation.
Nonpharmacologic treatment
The allergens should be avoided (see our tips under the hay fever article). If eyes are rubbed frequently, hands should be washed regularly to avoid superinfections. Regular washing of the eyes with eye washes or an eye bath can mechanically remove pollen, and cool compresses symptomatically relieve discomfort.
Drug treatment
Antihistamine eye drops:
- Such as azelastine, emedastine, epinastine, levocabastine, ketotifen, and olopatadine are placed in the eyes two to a maximum of four times daily. Compared with internal treatment, fewer adverse effects occur. However, locally applied antihistamines can also be absorbed into the body. They are partially effective against a simultaneous allergic rhinitis, since there is a connection between the eye and the nose.
Oral antihistamines:
- Such as cetirizine, loratadine and fexofenadine are taken as a tablet once a day. Oral use also helps with associated symptoms such as allergic rhinitis and hives, but potentially has more adverse effects than topical therapy.
Mast cell stabilizers:
- Such as cromoglicic acid are used in the form of eye drops and sometimes orally in the form of tablets. According to the evidence to date, they are well tolerated, but the onset of action is delayed. Most ocular antihistamines also have mast cell stabilizing properties.
Glucocorticoid eye drops:
- With active ingredients such as dexamethasone, fluorometholone, hydrocortisone, prednisolone or rimexolone have a strong anti-inflammatory and anti-allergic effect, but should be used only in the short term and with restraint in severe cases, as they lead to adverse effects (glaucoma, cataract, immunosuppression), especially with prolonged use.
Tear substitutes:
- Moisturize and care for irritated eyes and can be administered several times a day, as they do not contain pharmaceutical agents.
Sympathomimetics:
- Such as tetryzoline, naphazoline, and phenylephrine are used in the form of eye drops alone or in combination with antihistamines. They have a vasoconstrictive effect, are not antiallergic, and may cause reactive hyperemia. Therefore, they should be used only very cautiously during short durations.
Ectoin:
- Is a natural substance from salt-loving bacteria with cell-protective, anti-inflammatory and moisturizing properties. It is administered in the form of eye drops for the treatment of allergic conjunctivitis.
Other options:
- Eyebright eye drops
- Desensitization
