With the improvement of people’s living conditions and changes in the human living environment, allergic diseases are growing rapidly and have become a global disease that seriously affects human health in the 21st century. The World Allergy Organization (WAO) and the World Health Organization (WHO) jointly decided to designate July 8 as “World Allergy Day”. This year, July 8 is the 6th World Allergy Day.
1. Definition of allergy.
Allergy is a phenomenon in which the body’s perception of certain drugs or external stimuli is abnormally increased. Allergic reactions are tissue damage or dysfunction that occurs when an organism that has developed immunity receives the same antigen again. Allergy can be mediated by humoral (antibodies) or cellular immune mechanisms.
Allergies (allergic) are medically classified into four different categories and are named by the Roman numerals I through IV. The most common types are I and IV. Type I is sometimes called “tachyphylaxis”. For example, the body reacts within seconds to an insect sting, within minutes to animal hair and pollen allergies, and within 30 minutes to food allergies. In contrast, type IV allergies react much more slowly, with symptoms not appearing until a day or several days later. Examples include decorative allergies and many types of occupational allergies. For this reason, they are referred to as “delayed allergic reactions”.
The characteristics of allergic reactions are as follows.
(1) Rapid onset, strong reactions, and rapid remission;
②Usually no damage to tissue cells;
(3) There is a clear genetic predisposition and individual differences.
The mechanism of allergic reaction is a complex and abstract process, and the mechanism of allergic reaction can be divided into three stages.
① Sensitization phase: After the allergen enters the body, it can selectively induce allergen-specific b cells to produce antibody responses, and such antibodies bind to the surface of mast cells and basophils, and put the body in a sensitized state to the allergen. Usually this sensitized state can be maintained for several months or longer, but if the allergen is not exposed for a long time, the sensitized state can gradually disappear on its own.
The excitation phase: When the same allergen enters the body again, it causes the release of biologically active mediators from the sensitized mast cells and basophils by binding specifically to the antibodies on the surface of these cells. In this stage, the released bioactive mediators can be prostaglandin d2, leukotrienes, platelet activating factor, etc. in addition to histamine, but they all have similar effects, causing smooth muscle contraction, capillary dilation and increased permeability, and increased glandular secretion.
③Effect phase: refers to the phase in which bioactive mediators act on the effecting tissues and organs, causing local or systemic allergic reactions. According to the rapidity and duration of the reaction, it can be divided into two types: early phase reaction and late phase reaction. Early phase reactions are mainly caused by histamine and usually occur within seconds of contact with the allergen and can last for several hours. Late phase reactions are caused by leukotrienes and platelet-activating factor and occur 6 to 12 hours after allergen stimulation and can last for several days.
2.What causes allergy? First, allergens are needed.
The substance that causes an allergic reaction is called an allergen. Most allergens that react with IgE and IgG antibodies are proteins. In some cases carbohydrates and low molecular chemicals can also act as allergens. Allergens are necessary for allergies to occur. There are 2,000-3,000 common antigenic substances that cause allergic reactions, and close to 20,000 in the medical literature. They cause allergy in the organism by inhalation, ingestion, injection or contact. Common allergens are as follows.
A. Inhaled allergens: such as pollen, willow, dust, mites, animal dander, oil fumes, paint, car exhaust, gas, cigarettes, etc.
B. Ingested allergens: such as milk, eggs, fish and shrimp, beef and mutton, seafood, animal fat, penicillin, allogeneic proteins, alcohol, drugs, antibacterial agents, anti-inflammatory drugs, fragrance oils, flavors, onions, ginger, garlic, and some vegetables, fruits, etc.
C, contact allergens: such as cold air, hot air, ultraviolet light, radiation, cosmetics, shampoo, detergent, hair dye, soap, chemical fiber products, plastic, metal jewelry (watches, necklaces, rings, earrings), bacteria, mold, viruses, parasites, etc.
D, injectable allergens: such as penicillin, streptomycin, heterologous serum, etc.
E, own tissue antigens: mental tension, work stress, microbial infection, ionizing radiation, burns and other biological and physical and chemical factors that change the structure or composition of own tissue antigens, as well as their own hidden antigens released due to trauma or infection, can also become allergens.
3.What causes allergy? Second, allergic constitution is required. (Why is not everyone allergic to allergenic substances?)
Allergic constitution clinically refers to individuals who are highly reactive to IgE antibodies, and the specific reactivity has individual and/or family tendencies. And it occurs mostly in childhood or adolescence. Sensitization occurs when these individuals are first exposed to allergens (proteins) and produce the corresponding IgE antibodies. People with “allergies” can have different allergic reactions and allergic diseases, such as eczema, urticaria, allergic purpura, and even purpura nephritis. Early and complete desensitization is the key to the recurrence of allergic diseases.
4.The performance of allergy
Allergic manifestations often appear after half an hour to several hours of contact with the allergen. The general symptoms are as follows: flushing of cheeks, nose and earlobes, moist ear canal, earache, nasal congestion, sneezing, dark circles under the eyes, swollen and drooping eyelids, headache, dry lips, dry or sweaty skin, wrinkles at the corners of the eyes or palms, abdominal pain, diarrhea, bloating, constipation, eczema on the arms, legs or joints, cough, asthma, shallow and fast or irregular breathing, pulse disturbance, increased blood pressure, tight joints, etc.
5.Allergy prevention and control methods
To prevent allergy, the key is to find the allergen.
First, you should recall what you ate, what you touched, what you smelled and where you went before the allergic reaction.
Secondly, attention should be paid to good indoor hygiene, rooms with air conditioning should be ventilated frequently, and bedding should be dried regularly. Underwear should be washed twice more with water to avoid allergies to cleaning agents. After moving into a new home, home renovation, purchase of new furniture, spray insecticide, should open the door and windows, to be no indoor “smell”, and then enter. When you go out, choose a route with less motor vehicles and try to stay away from the exhaust of cars. Do not stay near factories.
Once the allergen is clearly identified, continue contact with the allergen should be stopped immediately and the allergic reaction usually disappears naturally.
Severe cases should be treated in hospital.
6, Allergic purpura is the most common allergic disease, epidemiological studies suggest that the incidence of allergic purpura is (13. 5-18. 0)/100,000, and the preferred age is 3-10 years old.
Allergic purpura, also known as Hen-Schu syndrome, is a relatively common microvascular allergic hemorrhagic disease. The causes include infections, food allergies, drug allergies, allergies due to pollen and insect bites, etc., but the cause of allergy is often difficult to determine. It is more common in children and adolescents, and more common in males than females, often with a history of upper respiratory tract infection 1 to 3 weeks before the onset of the disease. The basic lesion is the inflammatory reaction of capillary wall, increased permeability of capillaries, plasma and blood cell exudation, causing edema and hemorrhage.
The pathogenesis of allergic purpura has the following two types of conditions.
1) Rapid allergic reaction: by the combination of allergens and proteins in the body, forming antigens. The IgE antibodies produced adsorb to the mast cells and release histamine and slow-reacting substances (SRS-A). These substances cause dilation of small arteries and capillaries and increased vascular permeability.
2) Immune response: This is due to the formation of antigen-antibody complexes. These soluble, small-molecule complexes can stimulate histamine and 5-hydroxytryptamine release from basophils, and can also be deposited on the vessel wall and basement membrane of glomeruli to activate complement, causing tissue damage.
Allergic purpura is manifested as skin spots, mostly around the joints of lower limbs and buttocks, the purpura is symmetrically distributed, appearing in batches, varying in size and color, and can fuse into patches, generally fading within a few days, but can recur; allergic purpura can be divided into the following types according to its symptoms and signs.
1)Simple type;
2) abdominal type;
3) Joint type;
4) renal type;
5) Mixed type;
6) Others: In addition to the above common types, a few patients with the disease may also develop optic nerve atrophy, iritis, retinal hemorrhage and edema, and central nervous system-related symptoms and signs due to lesions involving the eye, brain and meningeal vessels.
Because of the many complications, high recurrence rate, prolonged course and increasing prevalence, research on allergic purpura has become one of the hot spots of allergic disease research in recent years.
Modern medicine has no satisfactory efficacy in the treatment of this disease, the use of hormones and immunosuppressants is inaccurate, and retrospective studies have found that they cannot reduce or effectively stop the progression of vascular damage, and have greater side effects and are prone to relapse. In contrast, Chinese medicine has shown obvious advantages in the treatment of this disease, and has been affirmed by the majority of patients for its efficacy, less susceptibility to relapse, and less toxic side effects, with more clinical reports.
Attachment.
Diagnostic criteria of allergic purpura
1, the examination of blood routine: blood cells mild to moderate increase eosinophils normal or increased, bleeding can be more anemic, clotting time platelet count, clot contraction time are normal.
2.Blood sedimentation: most patients have increased blood sedimentation
3.Anti-O: may be increased
4.Serum immunoglobulin: serum IgA may be increased
5.Urinary routine: protein red blood cells or tubular type may appear in the urine of those with kidney involvement.
6.Blood urea nitrogen and kegan: increased in renal insufficiency
7.Fecal occult blood: positive type in case of gastrointestinal bleeding
8, capillary fragility test: about half of the patients are positive
9, kidney tissue biopsy: can determine the nature of the nephritis lesion has a guiding significance for the determination of treatment and prognosis.
Allergic purpura diagnosis points
1.More history of infection, food, drugs, pollen, insect bite, vaccination, etc.
2, there are typical characteristic skin purpura, combined with joint, gastrointestinal or renal symptoms and history of recurrent attacks.
3, Increased leukocytes and eosinophils in whole blood, and decreased red blood cells and hemoglobin when bleeding is severe.
4.Blood sedimentation is increased, CPR may be positive, and serum IgA is increased.
5.When there is renal damage, hematuria and proteinuria can be seen.
Allergic purpura auxiliary examination
1, blood test: no anemia platelet count is normal, white blood cell count is normal or mildly increased, clotting time is normal.
2, bone marrow image: normal bone marrow image eosinophils may be high.
3, urine examination: there may be protein red blood cells, white blood cells and tubular type.
4.Fecal routine examination: some patients can see parasite eggs and erythrocyte occult blood test may be positive.
5.Capillary fragility test: positive
6.Pathological examination: diffuse small-vessel perivasculitis neutrophil aggregation around blood vessels. Immunofluorescence examination shows the presence of IgA and C3 deposited in the dermal vascular wall.
Differential diagnosis of allergic purpura
1, Idiopathic thrombocytopenic purpura is not difficult to identify based on the morphology of skin purpura not higher than the skin, asymmetric distribution and reduced platelet count. If the rash of allergic purpura is accompanied by angioneurotic edema, urticaria or polymorphic erythema, it is easier to distinguish.
The rash caused by septic meningococcal septicemia is similar to purpura, but the symptoms of toxicity are heavy and the leukocytes are significantly higher, and the smear at the puncture rash can be positive.
3, rheumatoid arthritis both can have joint swelling and pain and low fever, before the appearance of purpura is difficult to distinguish, with the development of the disease, the skin purpura, it will help to distinguish.
4, intestinal trapping is mostly seen in infants and children. If the child cries, abdominal masses, abdominal muscle tension should be suspected of this disease. Barium enema can be identified. However, allergic purpura can be accompanied by intestinal loop, so it should be noted.
5, appendicitis both can appear around the umbilicus and right lower abdominal pain with pressure pain. But allergic purpura abdominal muscle is not tense, skin purpura, can be distinguished.
Allergic purpura treatment principles
1, try to remove the allergy-causing factors.
2, simple person can use compound rutin, calcium, vitamin C, anti-histamine preparation.
3, fever and arthritis can be used corticosteroids, but can not stop the kidney invasion, for recalcitrant chronic nephritis can add free inhibitors.
4, Chinese medicine: according to the clinical symptoms of the disease identification and treatment.
Allergic purpura western medical treatment
1.Anti-allergic drugs: Xyosmin, paracetamol, calcium gluconate.
2.Reducing vascular permeability drugs: Aniloxin, rutin, vitamin C.
3, platelet aggregation inhibitor: Pansentin
4.Adrenocorticotropic hormone: hydrocortisone, prednisone (prednisone), dexamethasone.
5, for the renal type or prednisone treatment is not good, also use adrenocorticotropic hormone therapy and immunosuppressive drugs (such as cyclophosphamide, azathioprine and other chemotherapy drugs.
Allopathic treatment
1, swollen and painful joints can be used aspirin (see the section on rheumatic fever).
2, abdominal pain, sedatives, such as luminal, etc., while observing the abdomen for signs of intestinal loop.
3, gastrointestinal bleeding, a small amount of restriction of diet, a large amount of fasting, can also use procaine (should first do allergy test, negative, the party selected) for intravenous closure, with 8 to 15 mg / kg / day into 10% glucose 200 ml intravenous drip, 7 to 10 days as a course.
4, with infection, especially streptococcal infection, available penicillin and other antibacterial agents to control infection.
5. For those with intestinal parasites, deworming must be done after the gastrointestinal bleeding has stopped.
6.Persons with lesions, such as dental caries, sinusitis, tonsillitis, etc. should be treated thoroughly.
7.Generally, vitamin C, P or calcium can be supplemented.
8.Blood transfusion can be given to those who bleed a lot and cause anemia.
Rehabilitation guidance
Prevention of the disease “to avoid its poisonous gas” measures are mainly the following aspects: 1.
1, prevention of respiratory tract infection;
2, diet in moderation;
3, regulate the mood to keep the mood of relaxation and happiness
Life conditioning.
1, often participate in physical exercise to enhance physical fitness, prevent colds;
2, actively remove infections to prevent upper respiratory tract infections;
3, as far as possible to identify allergens;
4, the acute period and bleeding should be restricted when the patient’s activities.
Points to note in daily life
1, pay attention to rest, avoid strain, avoid mood swings and mental stimulation. Prevent insect bites. Remove possible allergens.
2, pay attention to keep warm and prevent cold. Control and prevent infection, use sensitive antibiotics when there is a clear infection or foci of infection, but should avoid the blind prophylactic use of antibiotics.
3, pay attention to diet, because allergic purpura is mostly caused by allergens, should be prohibited to eat raw onion, raw garlic, chili, alcohol and other irritating food; meat, seafood, should avoid contact with pollen and other allergens.
4, in order to prevent recurrence, patients should adhere to consolidation treatment after cure.