1. What is an allergic disease?
An allergic reaction, also known as a metamorphosis, is an abnormal reaction of the body to one or more substances that are not harmful to most people. The main reason is that the body of the allergic reaction patient produces too much of a special antibody called immunoglobulin E (IgE), which can react with the allergenic substances (allergens) in the environment and stimulate the body to produce and release certain excessive chemicals, and then produce various symptoms, such as: nasal symptoms (nasal itching, sneezing, running snot, nasal congestion, etc.), lower respiratory symptoms (shortness of breath, chest tightness, coughing, wheezing, etc.), and eye symptoms (eye problems). (shortness of breath, chest tightness, coughing, wheezing, etc.), eye symptoms (itchy eyes, tearing, etc.), skin symptoms (hives, eczema, etc.).
2.What are the allergic diseases?
Allergic diseases are one of the common diseases that affect people’s quality of life and may even be life-threatening. Common allergic diseases include asthma, allergic rhinitis, allergic skin diseases, drug allergy, food allergy, anaphylaxis, etc.
Nose: nasal itching, sneezing, clear watery snot, nasal congestion.
Lungs: chest tightness, shortness of breath, cough, wheezing.
Eyes: itchy eyes, tearing, conjunctival congestion.
Skin: red rash with itchy skin, white or red wind clumps with itchy skin.
Digestive tract: stomach cramps, vomiting, diarrhea.
3.What are antigens?
An irritant that can cause an immune or allergic reaction in the body. It is foreign to the body and is an inseparable pair with the composition of the antibodies it triggers.
Antigens have three basic characteristics.
First, immunogenicity: antigens can cause an immune response when they enter the body, that is, they stimulate the body’s immune system and produce antibodies or sensitized lymphocytes.
Second, immunoreactivity: the antigen can produce a specific reaction with the resulting antibody or sensitized lymphocytes.
Third, immune tolerance: when the immune function is not yet mature or immune function is suppressed, the antigen entering the body can not cause an immune response.
Antigen is a macromolecular substance, generally protein or protein-containing complex, but in addition to protein, lipids or polysaccharides can also participate in the metabolic reaction as semi-antigens.
Antigens can be divided into two categories: complete antigens and semi-antigens. Most proteins and bacteria and viruses are macromolecules that are immunogenic and immunoreactive in their own right, so they are called complete antigens. Polysaccharide lipids and some chemicals are small molecules, they are only immunoreactive and not immunogenic, so they belong to incomplete antigens, also known as semi-antigens, semi-antigens have immunogenicity only after combining with proteins, to work as complete antigens.
4.What are the common allergens?
Antigens that induce allergic reactions are called allergens. There are hundreds of antigenic substances that cause allergic reactions, and they sensitize the body through inhalation, ingestion, injection or contact.
Inhaled allergens: mites, pollen, willow, dust, animal dander, oil smoke, paint, car exhaust, gas, cigarettes, etc.
Ingested allergens: certain drugs, food, especially fish, eggs, milk and nuts, etc.
Contact allergens: cold air, hot air, ultraviolet light, radiation, cosmetics, shampoo, hair dye, detergent, chemical fiber products, metal jewelry (watches, necklaces, rings), bacteria, mold, viruses, parasites, etc.
Injectable allergens: penicillin, streptomycin, heterologous serum, etc.
Other allergens: mental tension, work stress, infection by microorganisms, ionizing radiation, burns and other biological and physical and chemical factors that change the structure or composition of their own tissue antigens, etc.
5.Fungi.
Fungi are divided into two categories, yeasts and molds. The main allergenic human body is mold. Therefore, sometimes fungi and molds can be used interchangeably.
Airborne fungi are common allergens that induce perennial allergy, and are usually divided into two categories: outdoor fungi and indoor fungi.
Outdoor fungi.
The most common outdoor fungi are Streptomyces interrogans and Dictyostelium, followed by Rhizopus and Fusarium spp. In the outdoor, most fungi in 18 to 320C and greater than 65% humidity environment to grow well (the rainy season in the south of China, the northern wheat harvest before and after, is the best period of mold growth). They grow on plants and in decaying vegetation, also from fertile soil and dead grass, and the spores they send out are dispersed in the air and are a major part of asthma triggers.
Ways to reduce exposure to outdoor fungi.
Patients who are allergic to outdoor fungi should stay indoors as much as possible during the season of attack.
Indoor fungi.
The most important of indoor fungi are Aspergillus spp. and Penicillium spp. (which are the green molds that emit from damp basements). Dark, damp, poorly ventilated rooms, especially basements are ideal places for fungal growth, followed by washrooms and kitchens, air conditioners and humidifiers can also be places for mold growth.
Ways to reduce exposure to indoor fungus.
Living rooms, washrooms, kitchens should be ventilated and dry; careful use of humidifiers and air conditioners and frequent cleaning; remove carpets as much as possible.
6. Pollen.
Trees, pasture and weeds three major types of plant pollen is spread by the wind, these pollen scattered in the air is an important source of airborne allergens, these pollen without fragrance, large number, light weight, wide spread area, can be with the wind to high altitude and distant fields and towns, is the main allergens that induce allergic diseases. The air is pollen particles can be as many as 800 per cubic meter on warm sunny days, generally the highest number before storms, and can be greatly reduced on rainy days.
Pollen and seasonality.
In spring, wind-borne pollen mostly originates from trees, such as: pine, cypress, poplar, elm, willow, birch, etc. Late spring and early summer wind-borne pollen mostly comes from pasture. Late summer and early autumn wind-borne pollen mostly comes from weed species. In our country to artemisia sin common, followed by quinoa, ragweed, grass, etc.. These grass pollen drifting time is long, causing heavier symptoms and longer duration of symptoms. 90% of hay fever is caused by pollen in summer and autumn. Take Artemisia as an example, 13 pollen particles per cubic meter of air can cause clinical symptoms.
Insect-borne flowers.
Insect-borne flowers are generally ornamental flowers, and their pollen can also cause allergic diseases. Common ones are chrysanthemums, incense flowers, dahlias, etc.
Ways to reduce exposure to pollen allergens.
During the pollen dispersal season, reduce outdoor activities as much as possible, stay indoors, close doors and windows; if you go out, it is best to wear a mask or stay in a closed car.
Be sure to close windows before rain and when it is windy. Try to stay away from clearly allergenic insect-borne flowers.
7. House dust and dust mites.
The most important inducer of allergic diseases in house dust is the dust mite belonging to Dermatophagoids. In China, 70% to 80% of allergic disease patients are allergic to dust mites. House dust mites (DerNaNeronyssinus) and dust mites (Der, farine) are the most common and important mites in this type of house dust. There are also cross allergens with them, such as Menei’s mite and storage mite.
House dust mites under the microscope are about 400 to 500 μm long and dust mites are about 300 to 400 μm long, and are small spider-like animals with eight legs. They grow and reproduce by eating up to 50 million skin scales shed per person per day. Each gram of house dust can contain up to 1350 dust mites, and the most common place where dust mites live – the bed – can contain two million dust mites.
Factors affecting mites in house dust.
Dust mites grow best in warm (18-30°C) and humid (RH 70%-80%) seasons. But even in extremely dry conditions, it takes several months for mites deep in sofas, carpets, or mattresses to die and for the level of allergens in the home to drop.
Dust mites and the seasons.
Dust mites are a perennial allergen, but levels of dust mite allergens in the living room are highest in the fall, so infants born in the fall have a younger age of onset of asthma, and those sensitized to dust mites tend to get sicker in the fall.
Methods to reduce exposure to dust mite allergens.
(1) Wash bedspreads, sheets, pillowcases and other bed knitted products regularly, preferably with hot water at 60℃. You can also use anti-mite bedspreads and pillowcases if you have the conditions.
(2), floor: Do not use carpet or upholstery, should use wood, tile or wood floor.
(3), room: room must be cleaned regularly, because the cleaning process is bound to make a large number of dust mites floating in the air, so dust mite allergic people cleaning, it is best to put on a dust mask or take shelter outside the house. You should always use a wet cloth to wipe the dust or use a powerful vacuum cleaner with a filter.
(4) Use air conditioners or dehumidifiers to keep the room dry; use air filters and regularly clean and replace the filters.
8.What is the skin prick test?
The skin prick test is performed by placing a small amount of highly purified allergen liquid on the patient’s forearm and then gently pricking the skin surface with a prick needle. If the patient is allergic to the allergen, a red swelling similar to a mosquito bite will appear at the site of the prick within 15 minutes. The skin prick test is now recognized as the most convenient, economical, safe and effective allergen diagnosis method in European countries and the United States, with the advantages of high safety and sensitivity, painless to the patient, just like a mosquito bite, and both the patient and the doctor can immediately know the test results.
9.What is the specific immunoglobulin E test?
Immunoglobulin E test, is the extraction of a patient’s blood sample, the use of chemical methods, the patient’s body to detect the specific immunoglobulin E content, its advantage is not affected by the patient taking antihistamines, the disadvantage is that the sensitivity is lower than the skin prick method, the patient can only know the results after several days, and the cost of the test than the skin prick test is expensive.