Allergic conjunctivitis is a very common condition and can occur for a number of reasons. In today's post we are going to focus on the main allergens that cause it. Causes red, watery, itchy and / or gritty eyes. The condition is usually not painful and there is usually no increased sensitivity of the eyes to light. It does not affect vision. The most common cause is allergy to mites in the population of the island of Tenerife, being responsible for at least 80% of cases, compared to other territories of the country where pollen, in the spring season causes the majority of the cases. Other causes are allergies to periocular cosmetics and problems related to contact lenses.
What is conjunctivitis?
Conjunctivitis is an inflammation of the conjunctiva. The conjunctiva is the thin "skin" that covers the whites of the eyes and the inside of the eyelids. It is made up of several layers of specially adapted transparent cells.
What causes conjunctivitis?
Infection is the most common cause of conjunctivitis and, in addition to itching, redness and gritty sensation, there is usually a sticky discharge. Many bacteria and viruses can cause conjunctivitis.
Irritative conjunctivitis occasionally occurs and can be confused with allergic conjunctivitis. For example, your conjunctiva may become red and inflamed after a little shampoo falls into your eyes. Pool chlorine is a common cause of irritative conjunctivitis.
Allergy is the other common cause of conjunctivitis. We must not forget that there are other processes that can affect the conjunctiva by sectors, we talk about diseases of the episclera and sclera that make up another part of the eyeball, which are below the conjunctiva and usually affect only one eye. These diseases should always be evaluated by a specialist in Ophthalmology because they can hide autoimmune processes that affect other organs of the body.
What causes allergic conjunctivitis?
Allergy means that the immune system overreacts to something that has become sensitive. Symptoms of increased immune activity include redness, increased tear secretion and itching. These are part of the body's defense mechanism to things that it considers strange and harmful. Causes include the following:
Seasonal conjunctivitis due to pollen and fungi.
Seasonal conjunctivitis appears in the same season every year.
Most cases are due to pollen and occur in the spring season. Symptoms tend to last a few weeks each year and may vary with the amount of pollen that exists in the atmosphere. Tree pollens can cause symptoms ranging from February or March to September, depending on when tree species that participate in the allergic process spread their pollen. Other pollens and fungi can cause symptoms in the summer. Other symptoms of allergic conjunctivitis can occur at the same time, such as a runny nose and itchy throat.
Perennial conjunctivitis: It is a conjunctivitis that persists throughout the year. This is most commonly due to an allergy to dust mites. House dust mites is a small insect that lives in every home. It lives mainly in bedrooms and mattresses, as part of the dust. People with perennial conjunctivitis usually also have perennial allergic rhinitis, which causes symptoms such as sneezing and a runny nose. Symptoms tend to be worse each morning when they wake up.
Animal allergies: Coming into contact with some animals can cause allergic conjunctivitis. This is usually due to allergy to the skin or hair of animals.
Giant papillary conjunctivitis: It is rare. It is an inflammation of the conjunctiva that covers the upper eyelid. More commonly by the use of contact lenses. It affects approximately 1 of each 100 contact lens wearers. The exact cause of the inflammation is unclear, possibly an allergic reaction to debris trapped behind a lens, contact lens preservation products or poor hygiene. It also sometimes develops after eye surgery.
Contact conjunctivitis: Some people become sensitized to cosmetics, makeup, eye drops, or other chemicals that come in contact with the conjunctiva. This causes an allergic response and symptoms of conjunctivitis. In this condition the skin on the eyelids can also become inflamed.
Finally, regarding possible complications, comment that seasonal and perennial conjunctivitis can be unpleasant, but complications are rare. If conjunctivitis is severe or there is a giant papillary conjunctivitis, they can occasionally cause inflammation and ulceration of the cornea. If you stop trying it can even lead to serious visual sequelae.
As you have seen, there are several types of allergic conjunctivitis; and each one has its treatment. In the next blog entry we will focus on the main treatments according to their causes.
Dr. Pedro Rocha Cabrera
Ophthalmologist. Specialized in eye inflammations.
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