Joke Collection Website - Mood Talk - Isn't pollen prolonging life? Can people with allergic rhinitis eat nutritious food of pollen?

Isn't pollen prolonging life? Can people with allergic rhinitis eat nutritious food of pollen?

Sensitized pollen

Pollen is the male organ of plants, which needs to be combined with female stamens to bear fruit, sow and reproduce. Male pollen can only reach stamens by external forces, mainly wind and insects. Those who pollinate by wind are called wind-borne flowers, and those who pollinate by insects are called insect-borne flowers. The main cause of allergy is anemophilous flowers.

In addition, foreign scholars have long recognized that pollen can cause allergies, and named it hay fever (now diagnosed as seasonal allergic eye rhinitis), which is caused by pollen diffusion after the grass in the field blooms. Fever does not mean that the patient has a fever, but that the patient is in a very excited state. China's understanding and research on pollen and pollinosis began at 1956, and the Allergy Department of Peking Union Medical College Hospital was established.

Allergic pollen mainly comes from trees, grass and weeds. They are all wind-pollinated anemophilous flowers. Its diameter varies from 10μm to100μ m. ..

1. Pollen of anemophilous flowers is an important source of airborne allergens. The pollen of these anemophilous flowers is not beautiful or fragrant, but light in color and abundant in quantity. The flower grains produced by each tree can release millions of pollen grains, and the pollen in the air exists for several hours to 4 ~ 5 days. The weight is also light, and some have airbags, which have a large deployment area. Before deposition, a few pollen grains in the air can even float to the altitude of 14000 meters with the wind, and fields and towns 200 kilometers away are the main pollen inducing allergies.

However, the farther away from the pollen source, the less air drift and the lighter induced symptoms. The amount of pollen scattered at different times of the day is related to the temperature, humidity, wind speed and direction of the air. For example, on sunny days, there are more pollen grains in the air, and on rainy days, pollen grains will suddenly fall. Pollen is sown for a long time, usually lasting several months.

(1) Spring Pollen: "In late spring and March, the grass grows in the south of the Yangtze River, the peanut trees are mixed, and the warblers fly around" is a famous sentence in Qiu Chi's Book with Chen Bo. It vividly depicts the scene that just after the severe winter, spring comes, everything recovers and prospers. In this beautiful time, spring hay fever also followed.

Does the pollen that causes hay fever in spring come from grass or trees? As can be seen from the above sentence, it is already late spring, and the grass in the south of the Yangtze River has just grown, and it is too late to blossom. At that time, the trees were full of all kinds of flowers. These sentences vividly describe that the pollen in spring mainly comes from trees. If we change "flock warblers" into "catkins", we can describe the scene of spring in Beijing more appropriately. Fortunately, the greening units in Beijing have made up their minds to change this situation and change the tree species structure, and the scene of "catkins flying around" will be greatly improved, or even become a thing of the past forever. People who are allergic to it will also benefit from these measures. Allergic pollen is also related to local planting conditions, climate and other factors.

Due to China's vast territory, the tree species suitable for planting vary from place to place. Casuarina equisetifolia, red sheep's hoof and melia azedarach are planted in many cities in South China, Platanus acerifolia is planted on both sides of central and southern cities, and cypress, pine, poplar, willow, elm, locust and birch are mainly planted in the north. These tree pollen later became an important local allergenic pollen. From south to north, the climate gradually turns cold, and spring comes late.

The flowering period of trees is also gradually moving back. For example, in Guangzhou in the south, February-April is the peak season for many trees to bloom, while in Harbin and Changchun in the north, the arrival of spring is already April-June. In spring, tree pollen floats in the air for a short time, so the symptoms it causes are generally mild and last for a short time, about ten days later.

(2) Pollen in late spring and early summer: mostly from pasture. 20% of the vegetation on the earth is pasture, and their pollen is all over the world during the pollination season. The pollen allergy caused by 10% ~ 30% IgE in the world is induced by grass pollen. They bloom from May to August.

(3) Pollen in late summer and early autumn: It belongs to weeds and is an important source of allergic pollen all over the world. In some parts of Asia, including China and Europe, wormwood pollen is the main allergen source, and wormwood likes dry and sandy areas. Followed by humulus scandens, commonly known as Larix gmelinii seedlings, and other weeds such as Chenopodium album. In the United States, it is mainly ragweed pollen.

These grass pollen have been floating for a long time. Generally speaking, 90% of pollinosis is caused by pollen in summer and autumn. Because there are few wasteland and weeds in the south of China, pollinosis induced by them is less, so pollinosis in summer and autumn is more common in the north. The peak of Artemisia pollen floating in the air is from June to 65438+ 10.

2. Insect-borne flowers are usually ornamental flowers, most of which are bright to attract bees, and the pollen is heavy and sticky, which is convenient for bees to spread pollination on their behalf. These characteristics make it difficult to be airborne, so it is quite rare to be sensitized by them. In addition, most plants growing indoors only have leaves, and they seldom bloom because of lack of sunlight, so there is no pollen.

Pathogenic mechanism

Pollen of wind-blown flowers is an important source of airborne allergens, and its diameter ranges from 10μm to100μ m. After sensitive person patients are exposed to pollen, most of the pollen grains can not reach the bronchi (those smaller than 5μm can be inhaled) except for the pollen grains that quickly spread above the glottis of the eyes and the wet surface of the upper respiratory tract.

How do they induce lower respiratory symptoms? The first possibility is that nasopharyngeal receptor reflex or allergens in pollen are absorbed by blood through mucosal surface, thus causing bronchial allergy. The second possibility is that some authors have observed that pollen allergen particles in the air can be as small as 0. 1μm, so they can be inhaled through the bronchus.

However, it is not clear how these allergic particles are released from pollen grains. Some authors think that dust can be used as a carrier. When pollen allergen comes into contact with sensitized mast cells in eyes, nose or bronchus, it degrankles the cells and releases inflammatory mediators such as histamine, which leads to a series of clinical symptoms.

clinical features

1. The appearance of obvious seasonal pollen symptoms has obvious seasonality, and the peak of pollen floats in the air. For example, in Beijing, people who are allergic to Artemisia pollen usually have symptoms from July to 10, and the symptoms are the most serious in August and September. The vast majority of patients complained by themselves. They became ill around beginning of autumn, but died before the National Day. A few patients are allergic to pollen in different seasons at the same time, so the onset time is longer. But this situation is rare. In the south, because flowers bloom all the year round and the onset seasons are connected, some patients are seasonally blurred.

2. The symptoms of hay fever are mainly allergic symptoms of the five senses, manifested as sneezing, even reaching dozens, clear nose constantly flowing out, nose, eyes, ears and palate itching unbearable. Nasal congestion is caused by congestion of nasal mucosa, so nasal congestion on both sides is not fixed, which often appears with the change of body position and relieves (lying on the left leads to right nasal congestion, whereas lying on the right leads to left nasal congestion). Conjunctiva congestion, redness, itching, tears. Most patients have only five allergic symptoms, and some have asthma after a few years, and their condition is getting worse year by year. Hay fever with skin allergy is rare. Only skin symptoms are rarer.

It has been more than ten days since the symptoms of pollen inducer were mild in spring. But more than 90% of people who are allergic to pollen are caused by weed pollen in summer and autumn. Weeds are the main source of sensitized pollen in the world in summer and autumn. Their symptoms are very serious and last for a long time, and they will disappear in February or so.

3. Age is generally more common in young people. Because it takes at least two years for pollen sensitization, the number of pollinosis patients increases gradually after 5 or 6 years old, and allergic babies are very few. However, a few people will get hay fever earlier. Many authors think it has something to do with the month and place of birth. For example, the month of birth happens to be the season of pollen flowering, and the birthplace is near the overgrown land.

Pollen disease with vegetable and fruit allergy

Oral hypersensitivity syndrome (OAS) refers to the local reaction of oral and/or pharyngeal mucosa mediated by IgE, such as itching and swelling of lips, tongue, palate and throat, which rarely involves other target organs in sensitive person within a few minutes after eating some vegetables and fruits (nuts and fruits), and the symptoms disappear quickly. This is a manifestation of contact urticaria.

A few patients may have severe systemic allergic reactions. OAS is more common in pollinosis patients. Foreign literature reports that about 35% of patients who are allergic to pollen are also allergic to fresh vegetables and fruits. However, according to our observation, about 10% of pollinosis patients will have systemic allergic symptoms after eating some fruits and vegetables, and only a few local symptoms. Adults seem to consume OAS in vegetables and fruits more easily than children. Israel found that vegetables and fruits are the most common sources of food allergens for children over 10. People who are allergic to these plant foods should be alert to hay fever in the future.

The existence of cross reaction

There is an obvious cross reaction between 1. pollen Fernadez. RAST and western blot confirmed that sunflower pollen was cross-reactive with other plants in Compositae such as Artemisia argyi, Artemisia anemarrhena, Taraxacum mongolicum, Hedyotis diffusa and ragweed. The effect of mugwort is the most obvious, and the effect of ragweed pollen is the weakest.

Although both wormwood and ragweed belong to Compositae, it seems that there is no obvious cross-reaction from the clinical skin test in our department. In Europe and America, the common sensitized pollen comes from mugwort, which belongs to mugwort. At present, it is used in China, and it is estimated to be a cross reaction. Because of the cross reaction, people who are allergic to pollen may also be allergic to similar plants.

2. There are also cross reactions between pollen and vegetables and fruits. Taking birch-fruit syndrome and mugwort-vegetable syndrome as examples, it mainly involves pollen of birch, mugwort and pasture. Through RAST inhibition test and protein blot technique, it was found that there were many allergens in vegetables, fruits and pollen. The relationship between birch pollen and Rosaceae fruit is the most obvious. The immunochemical basis of cross reaction is that there are * * * identical epitopes in the molecular structure of pollen, vegetables and fruits.

The cross reaction between birch and apple has been proved to be due to the fact that the main allergen Mald 1 in apple is very similar to the main allergen Betv 1 in birch. The amino acid sequence of Mald 1 is 63% identical to that of Betv 1. These allergens belong to a family, that is, pathogenesis-related proteins (PRP). PRP is ubiquitous in the plant world because it can protect plants from bacteria, viruses and fungi. The main allergen Apig 1 in celery is also PRP, and 60% of Apig 1 is homologous to Betv 1.

So patients with birch pollinosis often have symptoms after eating celery. Therefore, some patients who are allergic to birch pollen often avoid celery. Another allergen of mugwort is Artv 1, which is a pectate lyase. It is homologous to other pollen, such as amber 1 of ragweed, Cryj 1 of Japanese fir, celery and tomato.

The diagnosis of pollinosis and pollen allergy to vegetables and fruits is mediated by typical IgE.

1. Diagnosis of pollinosis:

(1) has a history of respiratory allergy induced by pollen, which is seasonal.

(2) Positive skin test and/or specific IgE test in vitro.

2. Diagnosis of pollinosis with vegetable and fruit allergy:

According to the medical history, and pollen and fresh vegetables or fruits are positive in skin test (pollen is generally in skin test, fresh vegetables or fruits are in skin test, and nuts can be mashed and pricked with a little physiological saline).

At present, the diagnosis of pollinosis allergic to vegetables and fruits are:

(1) has a history of respiratory allergy, such as allergic rhinitis/asthma symptoms;

(2) Have allergic history after eating (or inhaling) vegetables and fruits, such as oral mucosal contact urticaria, whole skin urticaria, laryngeal edema and even anaphylactic shock;

(3) The pollen skin test or in vitro specific IgE test was strongly positive;

(4) Skin prick test is positive for fresh vegetables and fruits and/or positive for specific IgE detection in vitro.

prevent and cure

1. Avoid pollen as an inevitable allergen. It is best to live indoors during the onset season, close the doors and windows, and reduce the entry of outdoor allergic pollen. This can also be achieved if there is air conditioning. Try not to go to the wild. If you are allergic to vegetables and fruits, you should avoid eating those allergic plant foods.

2. If the application of anti-inflammatory drugs has been diagnosed, anti-inflammatory drugs should be applied before the pollen season, such as topical corticosteroid Ai Le pine ointment. People with nasal allergic symptoms should be treated with nasal hormones or cromoglycine, and asthma can be prevented by oral inhalation of hormones or cromoglycine.

3. Patients who have symptoms with symptomatic drugs should be treated with some drugs. In addition to the above drugs, oral antihistamines should also be taken to relieve nasal symptoms, and attention should be paid to choosing antihistamines such as Kairuitan and decongestants such as Kairuitan to improve nasal congestion. Asthma can be treated by oral inhalation of antiasthmatic drugs, such as β2 receptor agonists, such as Chuanluning, Chuankangsu, salbutamol and corbett (β2 receptor agonists and ipratropium bromide). Serious illness requires hospitalization.

4. Immunotherapy As mentioned above, it is difficult to completely avoid wind-blown pollen. Therefore, immunotherapy (commonly known as desensitization therapy) has become the main preventive means of hay fever. The principle of immunotherapy is to gradually inject sensitive pollen extract from patients into patients from less to more (subcutaneous injection is the most commonly used immunotherapy, and subcutaneous injection has a better effect), which will cause immunological changes in patients and help improve patients' immunity to pollen. Many years of observation at home and abroad have confirmed that if the allergen is of high quality, applied properly, the case selection is appropriate and the method is correct, the effect is quite good. How long does immunotherapy last? There is no conclusion yet, but it is generally believed that effective cases should persist for 3 ~ 5 years. In patients who are allergic to vegetable and fruit pollen, although food-induced symptoms cannot be treated by immunotherapy, there is a cross reaction between pollen and vegetables or fruits. After immunotherapy with their sensitive pollen 1 year, not only the symptoms of hay fever have improved, but also a considerable number of patients can eat previously allergic foods.