Allergic conjunctivitis usually happens when a person’s eyes come into contact with an allergen, a substance that makes the body’s immune system overreact.
The eye becomes sore and inflamed. Symptoms occur because the overreacting immune system makes the body release histamine and other active substances through mast cells. The blood vessels dilate, or expand, and this irritates the nerve endings. The result is an increased secretion of tears.
Allergic conjunctivitis is different from infective conjunctivitis. The causes are different.
Pink or red eyes are a common symptom of conjunctivitis.
The following may offer relief:
Avoiding the allergen: Keeping the house clean, minimizing soft furnishings, and staying indoors when the pollen count is high can help.
Artificial tears: These eye drops dilute the allergen and help remove it.
Avoiding contact lenses: These should not be used until symptoms have completely disappeared. After using any medication on the eye, wait 24 hours after treatment has ended before wearing contact lenses.
Refraining from rubbing the eyes: Rubbing can make the inflammation worse. This can be difficult, as it is tempting to rub itchy eyes.
Cold compresses: Holding a wad of cotton wool soaked in cold water on the eyelid can soothe the eyes.
Drug treatment includes antihistamines, mast cell stabilizers, and occasionally, corticosteroids.
Antihistamines may help bring fast relief from symptoms, either as an oral dose or as eye drops. Antihistamines block the effects of histamines. The body produces histamines when the immune system reacts to a foreign substance.
Oral antihistamines for allergic conjunctivitis are cetirizine, fexofenadine, and loratadine. These are usually taken once a day. Antihistamine eye drops include Alaway and Zaditor. . The eye drops will relieve symptoms in the eyes, but the oral dose will also help treat a runny nose and other symptoms.
The most commonly prescribed antihistamine eye drops include azelastine, emedastine, and ketotifen. They are applied to the eyes two or three times a day.
Some antihistamines may cause drowsiness. People taking them for the first time should refrain from driving or operating heavy machinery until they know whether or not the medication affects them.
Mast cell stabilizers
Mast cell stabilizers take longer to bring relief than antihistamines, but once they start working, the effects last longer.
The most popular mast cell stabilizers are lodoxamide and nedocromil. They come in the form of eye drops.
Some patients take both antihistamines and mast cell stabilizers. The antihistamines provide some relief from symptoms before the mast cell stabilizers start working.
These are rarely prescribed, and only if symptoms are severe. Corticoid is a steroid hormone produced by the adrenal cortex. As a medication, synthetic corticosteroids can reduce swelling and decrease the body’s immune response.
Corticosteroids work well but should be used with caution and only short-term, because there may be side effects.
Most people with allergic conjunctivitis have problems with both eyes.
Symptoms may appear quickly, soon after the eyes come into contact with the allergen. In other cases, for example, if eye drops are causing a reaction, symptoms may appear after 2 to 4 days.
Symptoms of allergic conjunctivitis include:
Red or pink eyes: The eyes become irritated as the capillaries, or small blood vessels, widen in the conjunctiva.
Pain: This may affect one or both eyes. If a person has painful, red eyes, is sensitive to light, and their vision is affected, they should see a doctor at once.
Itchiness: As the eyes are irritated, they may itch. Rubbing can make the itchiness worse.
Swollen eyelids: The eyelids may puff up when the conjunctiva becomes inflamed, or if the person has been rubbing them a lot.
Soreness: The inflammation may make the whole area feel sore and tender. Some people say the soreness feels like burning.
People with seasonal allergic conjunctivitis will experience symptoms at certain times during the year, usually from early spring into summer, and sometimes into fall.
Those with perennial allergic conjunctivitis are susceptible at any time of year. They may find symptoms are worse at certain times of the day than at others.
If the eyelids are red, cracked, or dry, this may indicate contact conjunctivitis. Contact conjunctivitis and giant papillary conjunctivitis are not seasonal, and symptoms may occur at any time of year.
Pollen is a common cause of allergic conjunctivitis
Pollen is the most common allergen to cause conjunctivitis in countries that have cold winters.
If conjunctivitis results from pollen, there will likely be other symptoms, including sneezing, an itchy, blocked, or runny nose, and itchy and watery eyes.
Seasonal allergic conjunctivitis or allergic rhinoconjunctivitis is also known as hay fever.