As the name describes, allergic conjunctivitis is a disease the affects the conjunctiva of eye and results due to an allergic reaction. Knowing this condition better will help you understand the basic mechanism behind it and take measures against its occurrence.
An Introduction To Allergic Conjunctivitis
‘Conjuctiva’ is a thin, transparent layer that covers the white portion of eye. Conjunctivitis is a term used to refer to the inflammation of the conjunctiva, a condition that occurs due to variety of reasons.
What Causes Allergic Conjunctivitis?
Allergic conjunctivitis is an excessive reaction of the body’s immunological defense system upon exposure to some allergens (allergy-provoking substances). It appears as an inflammation of the conjunctiva and is characterized by allergic conjunctivitis symptoms redness and itchiness in the eyes. Excessive tears, pain, and swollen eyelids may also appear as symptoms in some cases.
Allergic Conjunctivitis – Some Common Allergens
- Pollen grains shed by plants, grass, and weeds (they account for most cases of this disease)
- Fur of animals/pets
- Objects of regular use, such as perfumes, deodorants, cosmetics, and other makeup materials
- Air pollution
- Eye medicines/devices, for example, eye drops and contact lenses
The Mechanism That Triggers Allergic Conjunctivitis
The basic mechanism that causes the allergic response of the eye is the sensitization of the conjunctiva to a particular substance (allergen). So whenever the conjunctiva is exposed to such an allergen, sensitization sets in to trigger an allergen-specific response, usually during subsequent exposures to such allergens.
Such an allergic reaction is associated with the release of chemicals like histamine, prostaglandins, interleukins, and allergy-specific antibodies (Immunoglobulin E or IgE).
The main cells involved in this cascade are ‘Mast cells’ and ‘T-helper cells’. Mast cells are components of the human body’s defense system and T-helper cells are a part of the white blood cells that protect the body from different foreign particles.
After exposure to allergens like pollen, T-helper cells release IgE antibodies that attach themselves to mast cells and activate them to release various chemical mediators like histamine and prostaglandins.
Histamine is responsible for the dilatation (widening) of the blood vessels of the conjunctiva. Excessively dilated blood vessels in the conjunctiva give it a “reddened look”.
As inflammation sets in, the conjunctiva becomes red and itchy. Excessive watering from the eyes and eye pain may supervene.
When Does Allergic Conjunctivitis Occur?
The symptoms of allergic conjunctivitis normally occur during seasons like summer and early spring, due to the high presence of pollen in the air during these times of the year.
Are You Prone To This Condition?
If you are prone to regular allergies, you might also be prone to allergic conjunctivitis. People with allergic diseases like asthma, hay fever, eczema, urticaria, and allergic dermatitis are also susceptible to allergic conjunctivitis.
Is Allergic Conjunctivitis Contagious?
Allergic conjunctivitis is not a communicable disease. Though other types of conjunctivitis may spread from one person to another, allergic conjunctivitis is restricted only to people with allergic hyper-responsiveness.
Types Of Allergic Conjunctivitis
Seasonal Allergic Conjunctivitis
It is the commonest form of ocular (eye) allergy. Seasons like early spring and summer are associated with the shedding of pollen from trees, weeds, and grass. An allergic response to these particles leads to a condition called ‘hay fever’. Additional symptoms like a runny nose, sore throat or sneezing may be seen. Seasonal allergic conjunctivitis may repeat every year at these particular times. Symptoms typically last for few weeks after the exposure.
Giant Papillary Conjunctivitis
It is a rare form of allergic conjunctivitis seen in contact lens users, usually due to poor maintenance of contact lenses. Allergy to the contact lens material or the debris retained behind contact lenses provokes this response.
Vernal And Atopic Conjunctivitis
Vernal conjunctivitis is seen in children residing in warm climates and atopic conjunctivitis occurs in males between 30 and 50 years of age.
It occurs as an allergic reaction to certain microorganisms (mainly TB bacilli, Chlamydia, etc.)
The Complications Of Allergic Conjunctivitis
Complications are rare with allergic conjunctivitis, but in cases where the condition is ignored or untreated, an infection may develop, especially if appropriate hygienic measures are not taken.
While it’s not a fatal disease, allergic conjunctivitis can nevertheless cause serious problems for the eye if not countered on time through allergic conjunctivitis treatment measures.