When a person’s eyes come into touch with an allergen, a chemical that causes the body’s immune system to respond, allergic conjunctivitis develops.
The eye gets inflamed and painful. The overactive immune system causes the body to produce histamine and other active compounds through mast cells, resulting in symptoms. The nerve terminals are irritated when blood vessels dilate or expand. As a result, the amount of tears secreted increases.
Infectious conjunctivitis differs from allergic conjunctivitis. The causes are not the same.
Causes
When the immune system overreacts to a substance, an allergic response occurs. The majority of people do not react to dust, pollen, or other substances in this way, but other people are more sensitive.
Allergens that typically cause allergic conjunctivitis include:
- eye drops
- make-up
- pollen, as in hay fever
- animal fur
- dust mites.
Types
There are different types of allergic conjunctivitis.
1) Seasonal allergic conjunctivitis or allergic rhinoconjunctivitis
In regions with cold winters, pollen is the most prevalent allergen that causes conjunctivitis.
Other symptoms of pollen-induced conjunctivitis include sneezing, an itchy, clogged, or runny nose, and itchy, watery eyes.
Hay fever is also known as seasonal allergic conjunctivitis or allergic rhinoconjunctivitis.
It generally takes place in the spring and summer. Plants, particularly grass, trees, and flowers, are in pollen during this time. Some people get symptoms in the early autumn.
2) Contact conjunctivitis
Cosmetics, eyedrops, or other chemicals that irritate the conjunctiva in people who are vulnerable induce symptoms known as contact dermatoconjunctivitis. An allergic reaction occurs when these compounds come into contact with the body. Some people are hypersensitive to certain chemicals.
After the substance comes into contact with the eyes, symptoms generally appear 2 to 4 days later.
3) Papillary conjunctivitis (giant papillary conjunctivitis)
This is a common side effect of wearing contact lenses. Contact lenses can be uncomfortable for some people. This might grow worse and more unpleasant with time, causing the eyes to become red.
When a person wears hard contact lenses following eye surgery, giant papillary conjunctivitis (GPC) can develop.
Infections of the eye can be caused by poor hygiene when handling contact lenses, solutions, and cases.
4) Perennial conjunctivitis
Perennial conjunctivitis is a kind of conjunctivitis that lasts all year. It is mostly caused by an allergy to home dust mites. These tiny insect-like critters like to reside in bedding, upholstered furniture, and carpets.
Dust mites feed on human skin cells and like warm, damp people.
An allergic reaction to a particular dust mite protein is known as dust-mite allergy. Conjunctivitis, a clogged or runny nose, sneezing, and airway tightness, as seen in asthma, are all symptoms of this.
Animal dander, minute scales from animal skins or hair, and bird feathers are among the other causes. Some people may experience an allergic response to them.
Treatment
The following suggestions may help:
- Cold compresses: The eyes can be soothed by placing a wad of cotton wool soaked in cold water on the eyelid.
- Avoiding the allergen: Staying indoors while the pollen count is high, keeping the house clean, and limiting soft furnishings can all help.
- Contact lenses should be avoided at all costs: These should not be used until all symptoms have vanished. After using any eye medicine, wait at least 24 hours before putting contact lenses back on.
- Artificial tears: These eye drops dilute the allergen and help remove it.
- Refraining from rubbing the eyes: Rubbing might aggravate the irritation. It’s tempting to touch inflamed eyes, so this might be challenging.
Antihistamines, mast cell stabilizers, and corticosteroids are used to treat the condition.
Antihistamines
Antihistamines, taken orally or as eye drops, may provide quick relief from symptoms. Histamines are blocked by antihistamines. When the immune system responds to a foreign substance, histamines are produced.
Cetirizine, fexofenadine, and loratadine are oral antihistamines used to treat allergic conjunctivitis. Once a day is generally plenty. Alaway and Zaditor are antihistamine eye drops. The eye drops will aid with eye problems, but the oral dose will help with a runny nose and other symptoms as well.
Azelastine, emedastine, and ketotifen are the most regularly prescribed antihistamine eye drops. They’re used twice or three times a day on the eyes.
Some antihistamines might make you sleepy. People who are taking them for the first time should avoid driving or using heavy machinery until they know how they will react to the drug.
Mast cell stabilizers
Mast cell stabilizers take longer to operate than antihistamines, but their effects stay longer once they do.
Lodoxamide and nedocromil are the most often used mast cell stabilizers. They are available as eye drops.
Antihistamines and mast cell stabilizers are used by certain patients. Before the mast cell stabilizers start acting, the antihistamines give some relief from symptoms.
Corticosteroids
These are only used in extreme cases and are rarely prescribed. The adrenal cortex produces corticoid, a steroid hormone. Synthetic corticosteroids are a type of drug that can reduce swelling and suppress the immune system.
Corticosteroids are effective, but they should be taken with caution and only for a short period of time due to the risk of adverse effects.
Symptoms
The majority of people who suffer from allergic conjunctivitis have issues with both eyes.
Symptoms may occur rapidly after coming into touch with the allergen in the eyes. Symptoms may develop after 2 to 4 days in other circumstances, such as when eye drops cause a response.
The following are some of the signs and symptoms of allergic conjunctivitis:
- Eyelids swollen: When the conjunctiva becomes inflamed or if the person rubs their eyes a lot, the eyelids may puff up.
- Soreness: The inflammation may cause pain and tenderness throughout the affected area. Some people describe the pain as burning.
- Red or pink eyes: As the capillaries, or small blood vessels, in the conjunctiva widen, the eyes become irritated.
- Pain: One or both eyes may be affected. If a person has painful, red eyes, is light sensitive, or has vision problems, they should see a doctor right away.
- Itchiness: Itching may occur as the eyes become irritated. Rubbing can aggravate the itching.
Seasonal allergic conjunctivitis affects people at specific seasons of the year, generally from early spring to summer and occasionally into fall.
Perennial allergic conjunctivitis patients are vulnerable at any time of year. They could notice that their symptoms are more severe at some times of the day than at others.
Contact conjunctivitis can be identified by red, cracked, or dry eyelids. The symptoms of contact conjunctivitis and giant papillary conjunctivitis are not seasonal, and they can appear at any time of year.
Diagnosis
A doctor will examine the patient and inquire about signs and symptoms such as sneezing and a runny nose to diagnose allergic conjunctivitis.
Other conditions with comparable symptoms may need to be ruled out as well.
Anyone experiencing the following symptoms should contact a doctor right once, since they might be signs of a more serious problem:
- vision problems
- very red eyes
- painful eyes
- sensitivity to light, or photophobia
Aside from allergic conjunctivitis, the following disorders can cause redness in the eyes:
- Keratitis: The cornea gets irritated and ulcerated on occasion. It can sometimes lead to corneal scarring, resulting in irreversible vision loss.
- Iritis: Iris inflammation is a condition in which the iris becomes inflamed. The iris may cling to the lens if left untreated, limiting critical fluid outflow from the pupil. It’s possible that irreparable eye damage will develop.
- Infective conjunctivitis: This is caused by bacteria or virus. It’s possible that it’s caused by the herpes virus, and it might signify a sexually transmitted infection (STI).
- Acute glaucoma: In the eye, pressure builds up. Symptoms might emerge quickly. Acute glaucoma, if left untreated, can result in irreversible visual loss.
Complications
The doctor will also look to see if the discomfort is caused by an item or substance, such as an eyelash.
If the patient’s symptoms are severe or worsening, the doctor may recommend them to an ophthalmologist, or eye specialist.
After recent eye surgery, anyone who gets papillary conjunctivitis will be sent to an ophthalmologist. To ensure that therapy is effective, the eye or eyes must be closely monitored.
Complications of allergic conjunctivitis, whether chronic or seasonal, are uncommon.
Allergic conjunctivitis can have a negative influence on a person’s quality of life, although it seldom has a long-term effect on health.
Dermatoconjunctivitis and large papillary conjunctivitis can also cause complications.
It’s possible that the cornea will get inflamed. Keratitis is a condition that causes ulcers to grow on the cornea. This raises the danger of scarring and the chance of vision loss for the rest of one’s life.
Keratitis symptoms include:
- blurred vision
- a feeling that there is something in the eye
- watery eyes
- intense pain in the eye
- sensitivity to light
If any of these symptoms appear, the person should seek medical attention.
Prevention
Finding out what causes allergic rhinitis and avoiding the allergen is the best method to prevent it.
Pet fur and pollen are two common allergies.
If your pet is the source of your allergy, try the following:
- wash their bedding regularly
- brush them regularly and wash them every 2 weeks
- keep pets out of the bedroom
If you’re going to a residence with a pet, taking an antihistamine one hour ahead of time may help alleviate symptoms.
If pollen causes an allergic response, do the following:
- use wraparound sunglasses to protect your eyes
- bathe and change your clothes after being outside
- try to get someone else to cut the lawn for you
- stay inside and keep doors and windows closed when the pollen count is high
- avoid areas with a lot of grass, flowers, or trees
Pollen counts are greatest in the mid-morning and early-evening hours.
If you have an allergic reaction to home dust mites, you should:
- choose anti-allergenic matresses and bedding
- vacuum often, and dust with a clean, damp cloth
- avoid soft furnishings, such as carpets and drapes
- use a vacuum cleaner with a HEPA filter
Sources:
- https://www.aop.org.uk/advice-and-support/for-patients/eye-conditions/allergic-conjunctivitis
- https://www.nhs.uk/conditions/allergic-rhinitis/prevention/
- https://www.medicalnewstoday.com/articles/157692
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049531/
- https://patient.info/health/allergic-conjunctivitis-leaflet
