Allergic conjunctivitis is caused due to the body’s overreaction to allergens (substances that provoke allergies) like pollen, perfumes, and animal fur. Different eye diseases often present similar symptoms, however, certain distinctive allergic conjunctivitis symptoms make it easy to distinguish this condition from other types of conjunctivitis and eye diseases.
Allergic Conjunctivitis Symptoms – An Overview
Some of the most common allergic conjunctivitis symptoms include:
Redness In The Eyes
The eye’s allergic response is associated with the release of chemical transmitters like histamine, prostaglandins, and interleukins. These substances cause the widening of the small blood vessels of the conjunctiva, and this process, known as vasodilation, makes the eyes appear red.
Intense itching in the eyes is the most common of all allergic conjunctivitis symptoms. It is seen in more than 75% of the cases of allergic conjunctivitis. Itching worsens when the eyes are rubbed. Histamine released from the mast cells (cells that provoke the allergic response of the eyes) irritates the nerve endings and causes an itching sensation in the eyes.
Foreign Body Sensation
The patient is likely to experience a constant feel of something stuck within the eye. Itchiness and swollen eyelids may cause this type of feeling.
The patient might experience a sharp pain in his eyes.
Excessive Watering Of The Eyes (Lacrymation)
The itchiness and inflammation trigger reflex tearing over time, causing the eyes to water.
Photophobia (Intolerance To Light)
As the symptoms worsen, the patient will lose the ability to tolerate bright lights.
Trouble With Routine Activities
Photophobia will make it difficult for the patient to carry out regular activities like driving, writing, reading, and working.
The inflamed lids may appear thick and swollen.
Nodule/Papillae Over The Eyelids
These do not appear in every case of allergic conjunctivitis. Nodules are small lumps seen with the phlyctenular type of allergic conjunctivitis.
Papillae are small, soft, and flat swellings along the insides of the eyelids, and are often seen in the giant papillary type of conjunctivitis.
When Do Allergic Conjunctivitis Symptoms Occur?
Unlike other types of conjunctivitis, allergic conjunctivitis has characteristic triggers for the onset of its symptoms:
- Seasonal Variation – Allergic conjunctivitis symptoms often occur during seasons like summer or early spring, when the pollen from trees, weeds, and grass are shed into the air. Exposure to such allergens may precipitate the symptoms of allergic conjunctivitis.
- Exposure To Allergens – Exposure to substances like pollen, animal hair, fur, bird feathers, perfumes, and cosmetics can also trigger this condition.
- Climate – A warm and dry climate worsens allergic conjunctivitis and aggravates its symptoms. But cool and moist weather conditions are soothing and comfortable for patients.
What Causes Allergic Conjunctivitis Symptoms?
When the conjunctiva is exposed to allergens such as pollen, the mast cells and T-helper cells in the body are activated. These cells release histamine, prostaglandins, and other chemical transmitters. Histamine causes vasodilation i.e. the widening of the blood vessels. It also irritates the nerve endings within the conjunctiva. The overall cascade manifests externally in the form of allergic conjunctivitis symptoms.
Identifying The Main Allergic Conjunctivitis Symptoms
Allergic conjunctivitis presents symptoms that often resemble other types of conjunctivitis and other eye diseases. But it does have certain distinguishing features:
- Seasonal onset and worsening of symptoms during warm and dry weather
- Repeated occurrence of the condition, specifically during summer and early spring every year
- Worsening of symptoms with increased exposure to specific substances like animal hair, feathers, pollen, etc.
- Association with other conditions like Hay fever, a runny nose, sneezing, and asthma
Laboratory Findings That Point To Allergic Conjunctivitis
Eosinophils are components of white blood cells, and they are specifically meant to tackle allergic diseases in the body. Most allergic conditions are characterized by an increased count of eosinophils (Eosinophilia) in the blood during the symptomatic phase. In allergic conjunctivitis, the eosinophil count in the blood is usually found to be higher than normal.
Skin test is a test conducted to evaluate a person’s response to certain allergens. If he/she is allergic to that substance, the skin test appears positive. So, if you have allergic conjunctivitis or any other associated allergic disease like asthma, you are likely to test positive on the skin test.
Immunoglobulin-E (IgE) is an antibody produced in the body in response to allergen exposure. IgE levels are normally found to be high in the blood of patients with allergic conjunctivitis.