Allergic conjunctivitis is a very common condition and can be caused by various factors. In today's post, we'll focus on the main allergens that trigger it. It causes red, watery, itchy eyes and/or a gritty sensation. The condition is usually painless, and there is typically no increased sensitivity to light. It does not affect vision. The most common cause is dust mite allergy among the population of Tenerife, accounting for at least 80% of cases, compared to other parts of the country where pollen, during the spring season, causes the majority of cases. Other causes include allergies to eye cosmetics and problems related to contact lenses.
What is conjunctivitis?
Conjunctivitis is an inflammation of the conjunctiva. The conjunctiva is the thin membrane that covers the white part of the eyes and the inner part 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 a gritty feeling, there is usually a sticky discharge. Many bacteria and viruses can cause conjunctivitis.
Irritative conjunctivitis sometimes occurs and can be mistaken for allergic conjunctivitis. For example, your conjunctiva may become red and inflamed after getting shampoo in your eyes. Chlorine in swimming pools is a common cause of irritative conjunctivitis.
Allergies are another common cause of conjunctivitis. It's important to remember that other conditions can affect the conjunctiva in specific areas. These include diseases of the episclera and sclera, which are another part of the eyeball located beneath the conjunctiva and usually affect only one eye. These conditions should always be evaluated by an ophthalmologist because they can mask autoimmune processes affecting other organs in the body.
What causes allergic conjunctivitis?
An allergy means that the immune system overreacts to something it has become sensitive to. Symptoms of increased immune activity include redness, increased tearing, and itching. These are part of the body's defense mechanism against things it perceives as foreign and harmful. Causes include the following:
Seasonal conjunctivitis due to pollen and fungi.
Seasonal conjunctivitis occurs in the same season every year.
Most cases are caused by pollen and occur during the spring season. Symptoms tend to last a few weeks each year and can vary depending on the amount of pollen in the atmosphere. Tree pollen can cause symptoms from February or March through September, depending on when the tree species involved in the allergic reaction release their pollen. Other pollens and molds can cause symptoms in the summer. Other symptoms of allergic conjunctivitis may occur at the same time, such as a runny nose and itchy throat.
Perennial conjunctivitis: This is conjunctivitis that persists throughout the year. It is most commonly caused by a dust mite allergy. House dust mites are tiny insects that live in every home. They live primarily 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. The symptoms tend to be worse each morning upon waking.
Animal allergies: Contact with some animals can cause allergic conjunctivitis. This is usually due to allergies to animal skin or fur.
Giant papillary conjunctivitis: This is rare. It is an inflammation of the conjunctiva, the membrane covering the upper eyelid. It is most commonly caused by contact lens use, affecting approximately 1 in 100 contact lens wearers. The exact cause of the inflammation is unclear, but it is possibly an allergic reaction to debris trapped behind a lens, to contact lens care products, or to poor hygiene. It can also sometimes develop after eye surgery.
Contact conjunctivitis: Some people become sensitive to cosmetics, makeup, eye drops, or other chemicals that come into contact with the conjunctiva. This triggers an allergic reaction and symptoms of conjunctivitis. In this condition, the skin on the eyelids may also become inflamed.
Finally, regarding possible complications, it's worth noting that while seasonal and perennial conjunctivitis can be unpleasant, complications are rare. Severe conjunctivitis, or giant papillary conjunctivitis, can occasionally cause inflammation and ulceration of the cornea. If left untreated, this can even lead to serious visual impairment.
As you have seen, there are several types of allergic conjunctivitis, and each has its own treatment. In the next blog post, we will focus on the main treatments based on their causes.
Dr. Pedro Rocha Cabrera
Ophthalmologist. Specialized in eye inflammations.
NIVARIA CLINIC