allergic conjunctivitis
Introduction
Introduction to allergic conjunctivitis Allergic eye disease is one of the most common ocular surface diseases, of which allergic conjunctivitis is the most common type. According to statistics, more than 5% of the world's people are treated for allergic eye diseases, and the proportion of allergic conjunctivitis is more than 50%. In recent years, the incidence of eye cosmetics has increased further due to factors such as the use of eye cosmetics, wearing contact lenses, and increased air pollution. Therefore, a correct understanding of allergic conjunctivitis and rational use of drugs is of great significance. Allergic conjunctivitis is a conjunctival hypersensitivity reaction caused by exposure to allergic antigens, which is mainly caused by IgE-mediated type I allergy. Anyone who is genetically or physically susceptible to a specific antigen may cause immediate or delayed allergic conjunctivitis when exposed to this antigen, often accompanied by allergic rhinitis. Seasonal allergic conjunctivitis is most common in young and middle-aged people, and the onset is rapid. Exposure to allergens can occur, and the symptoms of allergens are relieved. The main difference between perennial and seasonal is that allergic symptoms persist throughout the year. Contact allergic conjunctivitis has a clear history of exposure, such as a history of exposure to drugs or cosmetics. Giant papillary conjunctivitis often has a history of contact lens (contact lens). Spring keratoconjunctivitis is more common in children, often occurring or aggravated in spring and summer. Atopic conjunctivitis is more common in middle-aged men, with a history of mild allergies in the early stages. Certain spring keratoconjunctivitis and atopic conjunctivitis can cause severe corneal complications and even damage vision. basic knowledge The proportion of sickness: 0.01% Susceptible people: no specific population Mode of infection: non-infectious Complications: edema
Cause
Causes of allergic conjunctivitis
Environmental factors (30%):
Like all allergic diseases, allergic conjunctivitis occurs when the conjunctival mucosa of the eye is exposed to an allergen and is caused by inflammation of the conjunctiva. The allergens that cause allergic conjunctivitis are mostly substances that are easily accessible to the eyes such as pollen, dust, wet air, dust mites, and animal hair.
Physical and chemical factors (30%):
Secondly, perfumes, cosmetics, drugs, contact lenses and their care solutions that are often close to the eyes, these allergens enter the eye, causing the conjunctival mast cells to release sensitizing factors such as histamine, and these sensitizing factors make local The telangiectasia causes symptoms of redness, swelling, and itching in the eye.
Allergic conjunctivitis is mainly divided into four types: allergic conjunctiva (including seasonal, perennial, contact), giant papillary conjunctivitis, spring keratoconjunctivitis and atopic keratoconjunctivitis. Seasonal allergic conjunctivitis is most common in young and middle-aged people, and the onset is rapid. Exposure to allergens can occur, and the symptoms of allergens are relieved. The main difference between perennial and seasonal is that allergic symptoms persist throughout the year. Contact allergic conjunctivitis has a clear history of exposure, such as a history of exposure to drugs or cosmetics. Giant papillary conjunctivitis often has a history of contact lens (contact lens).
Prevention
Allergic conjunctivitis prevention
Children's tissues and organs are not yet mature, so the conjunctival mucosa is highly permeable, which naturally becomes a frequent population of allergic conjunctivitis. Adults with allergic conjunctivitis have a history of allergies in childhood due to their symptoms. Such as tears, burning sensation, secretions and the like and other ocular surface diseases, it is easy to misdiagnose. Therefore, it is important to remind everyone that when your child blinks frequently at a certain time, or if you have frequent blinks, you may have allergic conjunctivitis. Ordinary anti-inflammatory eye drops can't do anything, even Because long-term wrong treatment leads to the appearance of other diseases of the eye.
1. Develop a habit of blinking. Dry eye disease is a stress-type condition. The problem is that the eyes are staring in one direction for a long time. Therefore, the best way to avoid eye fatigue is to rest properly and avoid continuous operation. (1) It is very important to have a pair of suitable glasses. For those over 40 years old, it is best to use a bifocal lens, or wear glasses with a lower degree when typing. (2) The posture and distance of the work are also very important. Try to keep the distance at 60cm and adjust the most appropriate posture so that the line of sight can be kept down about 30°. This angle can relax the neck muscles, and Minimize the area of the surface of the eye that is exposed to the air.
2. For long-term computer operators, you should eat more fresh vegetables and fruits, and increase the intake of vitamins A, B1, C, and E. In order to prevent corneal dryness, dry eyes, decreased vision, and even night blindness, computer operators should eat more foods rich in vitamin A. Vitamin C can effectively inhibit cell oxidation. The main effects of vitamin E are: lowering cholesterol, removing rubbish from the body, and preventing cataracts. Walnuts and peanuts are rich in vitamin E. Vitamin B1 can nourish nerves, and green leafy vegetables contain a lot of vitamin B1. Green tea can be properly consumed every day, because the lipopolysaccharide in the tea can improve the hematopoietic function of the body, and the tea also has the function of preventing radiation damage.
3. In order to avoid the reflective or unclear screen, the computer should not be placed on the opposite side or the back of the window. The ambient lighting should be soft. If there is a window behind the operator, the curtain should be pulled up to avoid the bright light directly on the screen reflecting the bright image. Eye fatigue. Usually, the average person blinks less than 5 times per minute to dry the eyes. When a person works in front of a computer, the number of blinks is only one-third of the usual, thus reducing the secretion of lubricants and enzymes in the eye. You should blink more and let your eyes rest at least once every hour.
4. In order to reduce the dryness of the eye, the corneal nutrient solution can be appropriately used in the eye. Such as: good eyesight and other eye exercises can also relax the eyes and reduce the effect of visual fatigue.
Complication
Allergic conjunctivitis complications Complications edema
When allergic conjunctivitis occurs, the patient will feel the itchiness of the eye, causing the patient's attention to be unable to concentrate, seriously affecting people's work and life. Children will therefore affect their studies.
Vision effects. General allergic conjunctivitis does not affect vision, most of them can be cured in a short period of time, but some spring keratoconjunctivitis and atopic conjunctivitis can cause corneal complications and even damage vision, and severe cases may lead to blindness.
Affect people's quality of life. Symptoms such as itching, pain, and edema caused by allergic conjunctivitis. Will affect the patient's psychology and life. Causes a reduction in the quality of life of patients and their families. Can cause other allergic diseases. Because allergic conjunctivitis patients are allergic, it may cause allergic rhinitis, allergic asthma and other allergic diseases due to allergic conjunctivitis, which further burdens patients.
Strictly speaking, allergic reactions not only cause allergic conjunctivitis, but also affect other parts of the eye, resulting in more eye disease performance, and some consequences are more serious. New Vision Eye Hospital said that general allergic conjunctivitis has no effect on vision. Except for a small number of children who may affect the eyesight due to the involvement of the cornea (black eye), general allergic conjunctivitis does not cause great harm to vision. Most of the short-term can be cured. It is only after repeated episodes of spring conjunctivitis that will gradually stop as the age increases for a few years.
Symptom
Symptoms of allergic conjunctivitis common symptoms skin itching eye conjunctival edema and corneal ulcer conjunctival hyperemia eyes unbearable itchy eyes get angry
Itching is unbearable is the feeling of most patients with allergic conjunctivitis, in addition, conjunctival congestion, edema, mucous secretions, eyelid skin redness and other symptoms, and the closer to the corner of the eye, the more serious the situation, the patient generally has no eye pain, There was no obvious visual impairment and the pupil was normal. The symptoms will change with the seasons and recurrence, which means that in addition to accidents related to the patient's allergies, climate change and patient activities are important factors in the disease. Generally speaking, it is warm and dry, and the flowers are blooming. Symptoms will worsen in the days, and some patients may have nasal allergy symptoms in addition to eye discomfort. This condition is also known as allergic rhinitis conjunctivitis.
Spring keratoconjunctivitis is more common in children, often occurring or aggravated in spring and summer. Atopic conjunctivitis is more common in middle-aged men, with a history of mild allergies in the early stages. Certain spring keratoconjunctivitis and atopic conjunctivitis can cause severe corneal complications and even damage vision. Like all allergic diseases, allergic conjunctivitis occurs when the conjunctival mucosa of the eye is exposed to an allergen and is caused by inflammation of the conjunctiva.
Examine
Examination of allergic conjunctivitis
1. Conjunctival secretion smear and conjunctival scraping
In seasonally allergic conjunctivitis, perennial allergic conjunctivitis, and vernal keratoconjunctivitis, degenerative epithelial cells and eosinophils can be found in about half of patients. The positive rate of giant papillary conjunctivitis and atopic keratoconjunctivitis is Very low.
2. Quantitative analysis of IgE in tears
It is a semi-quantitative method to extract the tears from the inferior iliac crest by the acetic acid nitrocellulose membrane filter paper for quantitative IgE analysis. The method is simple to operate, but its sensitivity and specificity are not high. The presence of IgE in tears supports the diagnosis of allergic conjunctivitis to a certain extent, but the lack of IgE cannot rule out the diagnosis.
3. Skin test and conjunctival allergen challenge test
It can be used for the diagnosis of allergic diseases, the search for allergens, the observation of clinical manifestations caused by allergens, and the evaluation of the effects of anti-allergy treatments. This test is often used to identify allergens before desensitization. This test is mostly used for seasonal and perennial allergic conjunctivitis, but the positive rate is not high, and attention should be paid to the occurrence of false positives.
4. Imprinted cell examination
This is a non-invasive test. Increased degenerative epithelial cells and eosinophils are often found in patients with allergic conjunctivitis.
5. Conjunctival biopsy
Allergic conjunctivitis conjunctival biopsy is only used if other methods cannot be diagnosed, and is mainly used for the diagnosis of patients with suspected atopic keratitis (AKC).
6. Conjunctival scraper
The incidence of eosinophils in conjunctival scrapings in allergic conjunctivitis ranges from 20% to 80%. Scratch test eosinophilic negative does not rule out the diagnosis of allergic conjunctivitis.
7. Skin test
It has certain diagnostic value for confirming whether it responds to a suspected allergen. The test can be carried out on the surface of the skin, and if necessary, an intradermal test can also be carried out. The allergens usually to be detected include: tree grass, pollen meal and animal dander.
8. Radioactive allergen adsorption test (RAST)
It is one of the in vitro methods for determining in vitro specific IgE levels for a particular allergen. RAST is less sensitive than skin tests and is more expensive, so this method or other in vitro tests are only used when skin tests are not possible, such as patients with severe rashes and inability to discontinue antihistamines.
9. Detection of tryptase
Increased levels of tear tryptase can be detected in allergic conjunctivitis using sensitive immunoassays. Because tryptase is released from mast cells, the increase is limited to early responses. Determination of tryptase levels is of value in assessing the therapeutic effects of mast cell stabilizers.
10. Histological examination
Diagnosis
Diagnosis and differentiation of allergic conjunctivitis
Diagnostic criteria
Accurate and timely diagnosis is very important for symptomatic treatment of allergic diseases, which can timely control disease progression and reduce unnecessary damage. The diagnosis mainly has the following four aspects.
(1) Medical history: clear history of allergen exposure, or no specific allergen, but in a specific season, environment, climate, etc.; accompanied by other allergic diseases, this is atypical allergic conjunctiva for children The diagnosis of inflammation is decisive; the history of previous disease.
(2) Symptoms and signs: itchy eyes, red eyes, tears, photophobia, conjunctival nipples and follicles.
(3) The anti-allergy treatment effect is remarkable.
(4) Cytological examination or serum IgE level determination may contribute to the diagnosis of allergic conjunctivitis in children.
The disease is mainly differentiated from various types of infectious conjunctivitis.
