Pollen allergic asthma

　　Allergy is a kind of abnormal reaction of the body, an abnormal reaction of the human body to normal substances (allergens). Allergic reactions only occur when allergens contact people with allergic constitutions. There are hundreds of allergens, such as pollen, dust, heterologous proteins, chemicals, ultraviolet light, etc., and some allergies cannot find the allergen. The incidence rate of allergic diseases (including allergic syndromes) is about 20%. It occurs in all age groups from neonates to the elderly, without obvious gender characteristics, but with significant hereditary characteristics. Pollen allergy is caused by the oil and polysaccharide substances contained in pollen, which are digested by the nasal secretions after being inhaled, and then release more than ten kinds of antibodies. If these antibodies meet the invasive pollen and accumulate in large quantities, it will cause skin allergy.

　　Studies have shown that the frequent occurrence of allergic phenomena in recent years is mainly due to two aspects: on the one hand, it is due to the improvement of people's living standards, the intake of a large amount of high-protein, high-calorie foods such as eggs and meat products in their diet, resulting in an overactive ability to produce antibodies in the body. Therefore, when encountering allergens such as pollen, it is easier to have an allergic reaction. On the other hand, it is due to the widespread application of air pollution, water pollution, and food additives, which lead to more antigenic substances contacting the human body, promoting the occurrence of allergic diseases.

　　There are many types of allergenic pollen in the atmosphere, and different types of allergenic pollen can be found in different countries, regions, altitudes, and seasons. Due to the vast north-south span of China across the temperate and subtropical zones, the temperature changes greatly. In addition, the large east-west span, geographical and altitude influences, there are significant regional differences in the types of allergenic pollen. The pollen inhaled by pollen allergy sufferers often accompanies obvious upper respiratory symptoms, followed by cough, sputum, and allergic symptoms of the lower respiratory tract such as asthma.
　　

　　If pollen allergic asthma is not prevented and treated in time, it will lead to bacterial infections of the respiratory system; severe asthma may be forced to take a sitting position or assume a sitting breathing posture, with dry cough or expectoration of a large amount of white frothy sputum, and even cyanosis, which may even lead to pulmonary edema.

　　Before the onset of allergic asthma, there are prodromal symptoms such as sneezing, runny nose, coughing, chest tightness, etc. If not treated in time, asthma may occur due to the aggravation of bronchial obstruction, and severe cases may be forced to take a sitting position or assume a sitting breathing posture, with dry cough or expectoration of a large amount of white frothy sputum, and even cyanosis. But generally, it can be relieved by self-treatment or the use of bronchodilator drugs, etc. Some patients may have a recurrence several hours after relief, even leading to a persistent state of asthma.

　　People with allergic constitution should avoid contact with allergens, pay special attention during the prevalent season, and at the same time avoid inhaling dust or irritating gases, which have a good preventive effect on preventing asthma attacks. Severe allergic reactions should be desensitized under the guidance of a physician.

　　The doctor can diagnose pollen allergic asthma based on the results of the following examinations.
　　1. Blood Routine Examination:During an attack, there is an increase in eosinophils, and when complications occur, the total white blood cell count and neutrophils increase.
　　2. Sputum Examination:The sputum is usually thick and tenacious, with an increase in eosinophils. Schistocytes, which are formed by the degeneration of eosinophils, can be found in old sputum, and some severe cases may show Curschmann spirals.
　　3. Pulmonary Function Test:During an attack, all indicators related to expiratory airflow speed decrease, mainly including forced expiratory volume in one second (FEV1), forced vital capacity (FVC) per second (FRv1, %), and peak expiratory flow rate (PEF), which can be used for assessing the severity of the condition, treatment, and prognosis.

　　Patients' diets should be warm, light, and soft, with small and frequent meals. In addition to avoiding foods that are definitely allergenic or asthma-inducing, patients should avoid being too picky about other foods to maintain a balanced nutrition.

　　Irritating Foods
　　Generally speaking, spicy foods can dilate blood vessels and exacerbate pollen allergies, so pollen allergy sufferers should avoid eating them. In addition, they should also stay away from other irritant foods that can cause allergies, such as mutton, sweets, and alcohol. Apart from that, experts also suggest being cautious with wild vegetables. Eating wild vegetables can cause sensitivity to ultraviolet light, leading to skin redness and exacerbating pollen allergy symptoms.

　　High-Protein Diet
　　Research shows that with the improvement of living standards, people consume more high-protein, high-calorie foods such as eggs and meat products, which result in an overactive ability to produce antibodies in the body. Therefore, pollen allergy sufferers should try to eat less high-protein, high-calorie diets and avoid refined foods.

　　Raw Food
　　Differences in dietary habits can also lead to different occurrences of allergies, such as some Japanese who enjoy eating raw peanuts, many of whom have experienced oral allergic reactions. In contrast, Chinese people who like to eat fried peanuts as side dishes rarely suffer from allergies. Some Japanese scholars believe that the occurrence of peanut allergy may be due to the habit of eating raw peanuts. If the peanuts are heated before eating, the allergens in the food may change, and it may not cause an allergy.

　　Specific treatment for pollen-induced allergic asthma refers to etiological treatment measures taken against the allergenic pollen. Due to the strong specificity of specific treatment, the clinical efficacy is relatively certain, and the side effects are also rare.
　　1. Avoid Contact with Pollen
　　Avoiding contact with pollen is usually enough to prevent asthma attacks. However, in actual work, it is quite challenging to completely prevent patients from contacting pollen. When asthmatic patients are diagnosed with pollen allergy, the first step should be to try to clarify which type of pollen the patient is allergic to, so as to avoid or reduce contact with that type of pollen according to the dispersal situation of the pollen in the local atmosphere at the corresponding time.
　　2. Desensitization Therapy
　　Also known as specific immunotherapy or desensitization therapy, its purpose is to enhance the body's tolerance to the corresponding allergenic pollen. Currently, the most commonly used desensitization therapies in clinical practice mainly include the following 3 treatment plans.
　　Seasonal Allergen Desensitization Therapy:Treatment usually begins 3 months before the pollen season, with injections 2 to 3 times a week, gradually increasing the dosage of allergen injections from low to high concentration to reach a concentration of 1:100 before the season. This allows the body to produce enough IgG blocking antibodies when the pollen season arrives. Then, maintenance injections are given 1 to 2 times a week, and treatment can be stopped in the last month of the disease season.
　　Conventional immunotherapy:Conventional immunotherapy is a desensitization therapy carried out throughout the year, which aims to reach the maximum tolerance to the corresponding allergenic pollen within 3 to 4 months by gradually increasing the concentration of pollen extracts injected twice a week. At this time, the body can produce enough specific IgG blocking antibodies, thereby alleviating or eliminating the clinical symptoms of pollen allergic asthma patients. Then, a maintenance injection treatment of 1 to 2 times per week or even once every 2 weeks is used, and the interval of desensitization injections can be shortened to twice a week before the next pollen season arrives. Conventional immunotherapy usually requires continuous treatment for 3 to 5 years or more than 5 years to consolidate the efficacy.
　　Emergency immunotherapy:Emergency immunotherapy usually adopts a daily injection method or multiple injections per day, striving to reach the maximum tolerance to the corresponding allergenic pollen within 1 to 1 month, thereby preventing or alleviating clinical symptoms. Emergency immunotherapy can significantly shorten the course of specific immunotherapy, and can further shorten the treatment time when combined with pre-seasonal desensitization. However, some studies have shown that emergency immunotherapy can increase the late-phase asthma reaction, so it should be administered under the close observation of a specialist doctor and hospitalization should be considered, with careful use.
　　3. Preventive treatment
　　Prevention and treatment of pollen allergic asthma is relatively important, but due to the difficulty in implementing pollen prevention measures, treatment can be carried out on the basis of or at the same time as prevention measures. This includes measures such as mast cell membrane stabilizers, antihistamines, corticosteroids, etc.
　　4. Symptomatic treatment
　　Since the onset of allergic asthma due to pollen is usually mild, inhaling salbutamol inhaler and other β2-agonists can control the symptoms when asthma symptoms occur. In severe cases, β2-agonists can also be inhaled or taken orally in conjunction with systemic use of corticosteroids. Tea alkaloid drugs can also be used in combination. Patients with ocular allergic symptoms can use cromolyn sodium eye drops locally.