What is allergic conjunctivitis and how is it treated?

Conjunctivitis is an inflammatory process in the conjunctiva, the outer lining of the eyes, and the inner surface of the eyelids. Conjunctivitis occurs in both kids and adults. The main manifestations are redness, swelling of the eyes, and lacrimation.

Short information about allergic conjunctivitis

The disease can occur due to a bacterial or viral infection or as a response to allergens. People with a history of allergies in their family are more prone to the allergic type of the disease than others.

Although the triggering factors, i.e. allergens vary for different patients, the most frequent are the same that cause seasonal rhinitis – pollen of different plants. If the symptoms of conjunctivitis are accompanied by manifestations of rhinitis, i.e. itching in the nose, sneezing, nasal discharges, and congestion, the disease is called rhinoconjunctivitis.

The symptoms typical for the disease occur due to the production of histamine (a chemical that induces an immune response by the organism) and other active chemicals by the mast cells that stimulate the expansion of the blood vessels, irritate nerve endings, and enhance lacrimation.

The therapy is the most efficient if the allergen is identified and a patient can avoid it. Besides, antihistamines such as Allegra (Fexofenadine) in pills and eye drops are used. Also, nonsteroidal anti-inflammatory medications (NSAIDs) can be used to ease the inflammation.

What are the signs of allergic conjunctivitis?

The most frequent manifestations are:

- Reddening of the inner lining of the eyes;
- Burning and itching of the eyes;
- Increased lacrimation (tears formation).
Other possible but rarer symptoms are:
- Photophobia (sensitivity to light);
- Puffiness of the eyelids;
- Sensation of something in the eye.

Usually, the disease affects both eyes but the manifestations can be more intense in one eye. If the eyes are scratched, the symptoms worsen.

Allergic conjunctivitis is commonly accompanied by rhinitis that manifests in itching of the nose, nasal congestion, runny nose, and frequent sneezing.

Sometimes, the only present symptom is itching in the eyes. The manifestations aggravate in dry and warm weather and ease in chilly and rainy weather.

What are the reasons for allergic conjunctivitis occurrence?

The reason for the disease onset is the inadequate organism’s response to the harmless substances that are called allergens. Every person prone to allergy has their own allergens, i.e. triggers for the incorrect immune response, but there are the most wide-spread allergens typical for most people who suffer from different allergies.

Worth noting that the disease is more frequent in individuals with a history of allergy in family and other types of allergies, for instance, hay fever, eczema, and so on.

The most common allergens are:

- Pollen of different plants, trees, flowers, bushes, etc.
- Animal fur, dandruff, saliva, and so on;
- Perfumes;
- Cosmetics;
- Air pollution and bad environment;
- Medications applied to the skin;
- Smoke;
- Dust mite;
- Eye drops.

The majority of cases of allergic conjunctivitis is related to pollen and occurs at the beginning of summer. At the end of summer, during the blossoming of different flowers and spread of mole the manifestations can also occur.

Year-round conjunctivitis occurs usually due to the allergy to house dust mites.

How is allergic conjunctivitis diagnosed?

First, you need to visit an ophthalmologist to make sure that lacrimation and redness are caused precisely by an allergic response and not by other eye diseases. Diagnostic tests, such as conjunctiva scans for eosinophils, can help determine the cause of an allergic reaction. After this, it is advised to visit an allergist. He will help you figure out which allergens are triggering your symptoms and prescribe treatment.

Sometimes it is quite simple to determine an allergen, for this it is enough to analyze under what circumstances conjunctivitis occurs (for example, after contact with a cat or dog, during the flowering of poplars, etc.).

In chronic disease, this task is complicated but modern diagnostic methods come to the rescue. Among them are skin tests, when various allergens are injected under the skin. By the reaction at the injection site, it is possible to judge what triggers allergy.

How is allergic conjunctivitis treated?

The first step in allergic conjunctivitis is proper eye care. For the duration of the disease, refrain from using contact lenses and cosmetics. Do not rub your eyes with your hands, as this aggravates the symptoms. To alleviate the condition, you can apply cold compresses, as well as drip artificial tear preparations.

Try to minimize the effects of allergens. To minimize contact with pollen, if possible, stay indoors with air conditioning. Keep windows closed at home and in the car. Or use window and floor filters to clean the incoming air from pollen and other allergens.

For the therapy of allergic conjunctivitis, antihistamines and vasoconstrictor drops for the eyes, and mast cell stabilizers are used. At the same time, you need to know that vasoconstrictive eye drops can be used only for a short time, otherwise, they cause a number of serious side effects.

It is better to start taking antihistamines in advance, before the onset of symptoms. You can do this later, but you will have to wait a few days until their effect is manifested.

In chronic allergic conjunctivitis, immunotherapy may be recommended. The essence of the treatment is that small doses of allergens are injected into the body with the help of injections or tablets. The body gradually "learns" to properly respond to allergens.

Medicines for allergic conjuctivitis treatment

Topical anti-allergic medicines commonly used in ophthalmology

- Antihistamines. This group is first-line medications that can be usually purchased over-the-counter. The most effective ones include Allegra or its generics based on the same substance Fexofenadine, diphenhydramine, and chlorpheniramine. These medicines can eliminate the symptoms completely or at least make them less intense. It is preferable to use 2nd-generation antihistamines such as Allegra, although they are more expensive than the older medicines, they do not induce sleepiness, mind fog, and in general, have fewer adverse effects.

There are also medicines with a double effect – they are antihistamines that also stabilize mast cells involved in the allergic response. These medicines are Olopatadine (Patanol) and Ketotifen Fumarate (Alaway or Zaditor). If just antihistamines are ineffective, you can ask your doctor whether you can use the medicines with an additional effect.

- Mast cell stabilizers. Before considering this group of medicines it is preferable to check whether a cold compress is effective for you as if it is not, these medicines will not help either. The drugs diminish the release of inflammation-inducing chemicals from mast cells. They block the calcium channels stabilizing the cells thereby preventing the release of histamine. These medicines have a delayed result but also fewer adverse effects than antihistamines. The most appointed medicines from the group are lodoxamide and Nedocromil in eye drops. They are usually given after antihistamines that suppress the first intense symptoms.

- Immunotherapy. This method of treatment implies the insertion of small doses of allergen to get the body used to the harmless substances that in case of a particular patient cause allergy, i.e. pollen, dust mite, etc. This can ensure the body’s tolerance of the substances. The allergens can be taken orally in the form of sublingual pills or drops), or by injection under the skin (subcutaneously).

Post by: John Avery, General Practitioner, Manchester, United Kingdom