The most important thing is the benefit of spring, but many people suffer from "spring pain". In the warm spring season, sneezing, runny nose, nasal congestion, nasal itching, itchy eyes, red eyes, tears, itchy skin, rash, cough, wheezing... Have you been tricked by these symptoms? These symptoms, which are easily misdiagnosed as "colds", may actually be caused by pollen allergies. Friends with pollen allergy look over, today, let's follow the allergy doctor of Peking Union Medical College Hospital to learn the key points of prevention and treatment of pollen allergy ——
About the author: Du Zhirong
Postdoctoral Fellow in Clinical Medicine, Department of Allergy, Peking Union Medical College Hospital. Research interests: Clinical and mechanical research of severe allergic reactions.
Audit expert: Zhi Yuxiang
Chief Physician, Professor, Doctoral Supervisor, Department of Allergy, Peking Union Medical College Hospital. He specializes in the diagnosis and treatment of severe allergic diseases such as urticaria, angioedema, hereditary angioedema, allergic rhinitis, allergic asthma, severe refractory asthma, food allergies and severe allergic reactions, and anaphylactic shock.
What is pollen allergy?
Pollen allergy is a common allergic disease. Clinical manifestations can be allergic rhinitis, allergic conjunctivitis, allergic dermatitis, allergic asthma, etc.
The spread of pollen has obvious regional and seasonal characteristics, so the appearance of allergy symptoms is also closely related to the region and season. In the northern part of the mainland, people with pollen allergy tend to have symptoms in the spring (mid-March to May) and summer and autumn (July to September).
Which pollens are prone to allergies?
Allergenic pollen is mostly used by wind as a pollination medium, with large pollination production, long pollination period, light weight and small particles.
In the northern part of the mainland, the pollen that causes spring allergies is mainly from: birch trees, cypress trees, ash trees, plane trees, poplar trees and so on. In recent years, the incidence of allergic to cypress pollen in Beijing has been high, and cypress pollen has become a "breathing pain" for Beijing residents.
Common pollen that causes autumn allergies is artemisia, ground skin, turnips, ragweed, etc. Patients with pollen allergies in the fall are more likely to develop allergic asthma. According to the research of Professor Yin Jia of the Department of Allergy of Peking Union Medical College Hospital, 37% of all patients with pollen allergy in summer and autumn developed allergic asthma within 5 years and 46.7% of patients developed allergic asthma within 9 years.
Knowledge of pollen allergens can help effectively prevent allergenic pollen. Figure 1 shows common trees and their pollen that cause spring allergies. Figure 2 shows common weeds and their pollen that cause autumn allergies.
▲ Figure 1: A. Birch Powder B. Cypress Powder C. Ash Powder
▲Figure 2: A. Artemisia pollen B. Ground skin pollen C. Turnip pollen D. Ragweed pollen
What are the commonly used pollen allergen detection methods in clinical practice?
At present, the commonly used detection methods in clinical practice mainly include skin tests and serum-specific IgE (sIgE) tests. The main differences between the two detection methods are as follows.
How to scientifically prevent pollen allergy?
Prevention and treatment of pollen allergy is divided into general treatment, drug therapy and allergen-specific immunotherapy.
1. General treatment
1. Avoid contact with allergens, pollen allergy patients should stay indoors as much as possible during the pollen season, and keep the doors and windows closed to avoid going to areas with high pollen concentrations.
2. Wear goggles and masks, and use nasal pollen blockers.
3. Install fresh air system and air purifier indoors.
4. Nasal irrigation can be used as a safe and effective supplementary treatment for patients with allergic rhinitis.
2. Medication
1. Systematic medication
a. Antihistamine drugs
Current antihistamines can be divided into two generations. First-generation antihistamines (e.g., ketotifen) can antagonize histamine H1 receptors and inhibit the release of mediators of allergic reactions, but often cause central nervous system adverse reactions such as drowsiness and lethargy. Second-generation oral antihistamines (eg, cetirizine, loratadine, desloratadine, levocetirizine, etc.) are more selective for peripheral H1 receptors and have fewer side effects.
Antihistamines usually reduce itching, sneezing, and runny nose, but are less effective at nasal congestion than intranasal glucocorticoids.
b. Leukotriene receptor antagonists
For example, montelukast can be used to alleviate the symptoms of allergic rhinitis, and can also be used for the prevention and long-term treatment of asthma.
c. Mast cell membrane stabilizer
Second-line medication for allergic rhinitis. Such as sodium cromoglycate, can stabilize the cell membrane of mast cells, inhibit mast cell degranulation, inhibit the release of histamine, serotonin and other mediators of allergic reactions, thereby preventing or alleviating bronchial smooth muscle spasm, mucosal tissue oedema and increased vascular permeability.
d. Omalizumab
It is a monoclonal antibody against IgE, which has been approved in Countries such as Japan for the treatment of pollen allergy.
2. Topical medication
a. Glucocorticoid nasal spray
Such as beclomethasone, fluticasone, budesonide, mometasone furoate, etc., are currently effective single-drug maintenance treatment drugs for allergic rhinitis, and the therapeutic effect on nasal congestion is remarkable. Topical glucocorticoids are commonly used in the clinical treatment of allergic rhinitis and can be started prophylactically 2 weeks before the pollen season.
b. Antihistamine nasal spray
Such as azelastine nasal spray or olostatin nasal spray, used to treat allergic rhinitis.
c. Antihistamine eye drops
Such as azelastine eye drops or olopatadine eye drops, used to treat allergic conjunctivitis.
d. Decongestants
For example, naphazoline can reduce the symptoms of nasal congestion, but the use of this class of drugs should not exceed 1 week, otherwise it can cause drug-induced rhinitis.
3. Allergen-specific immunotherapy (AIT)
AIT refers to individuals with allergic diseases, by gradually increasing the dosage of allergen preparations to improve the clinical symptoms of subsequent exposure to the causative allergen. AIT is the only treatment for causes at this stage that can sustainably reduce allergy symptoms and is the only treatment that can alter the natural course of allergic diseases.
AIT treatment may be considered in the following conditions:
1. Moderate to severe onset of allergic rhinitis, FEV1 greater than 70% asthma.
2. Symptoms cannot be adequately controlled by avoiding allergens and conventional drug treatment.
3. Can not tolerate conventional drug therapy.
4. Patients hope that allergy symptoms will be improved for a long time.
Commonly used methods of administration for AIT include subcutaneous injection (SCIT) and sublingual administration (SLIT).
Before starting AIT treatment, serum-specific IgE or skin tests are needed to determine the type of allergen.
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Editor/Fan Xinchen Hong Chengwei
Editor-in-Chief/Chen Mingyan
Producer/Wu Peixin