## What is the reaction to? Each region of the world has its own list of the most aggressive plants in terms of allergies. For example, ragweed and nettle are among the most common causes of allergies in the United States. In Europe, chestnut, sycamore, and walnut are at the top of the list. Lilacs also cause allergies—ever heard of the term “lilac conjunctivitis"? ## How does an allergen work? During the flowering period, which lasts about 2–3 weeks for each plant, 5–6 thousand pollen particles are released into 1 m³ of air. One plant produces about a million pollen particles during the flowering season, and 500 particles are enough to start an allergic reaction. Typical manifestations of allergies are lacrimation, redness, and swelling of the eyelids, runny nose, irritation of the throat mucosa, perspiration, and dry cough. In more severe cases, difficulty breathing, bronchospasm, and asthmatic attacks can occur. ## Who is at risk? The culprit here is the violation of the protective functions of the upper respiratory tract in the first place, so people with chronic diseases of the nasopharynx and lungs are the most vulnerable. The region of residence is also important: in large cities, there are 6 times more allergy sufferers than in rural areas. The reason is exhaust fumes: it was proved at the Helmholtz Center in Munich that under the influence of nitric oxide, the protein composition of pollen changes, and additional antigens appear in it. And because of global warming, plants get more dust, and for longer periods of time. ## What should you do? You can reduce the risks by putting on a mask and glasses outside as well as minimizing being outdoors, especially in the morning and afternoon, and in sunny weather. However, in the most severe cases, allergists recommend leaving the region where the allergenic plant grows steadily. If leaving is not an option, only symptomatic treatment remains: taking medications that reduce or completely remove the manifestations of hay fever. The safest products are chromones, mast cell stabilizers. When allergens enter the body, mast cells produce histamines, which cause a runny nose and swelling. Most chromones have a cumulative effect, so you should start taking them at least two weeks before the beginning of the flowering season, and preferably a month before. The so-called "emergency" antihistamines reduce the manifestations of allergies literally within an hour or two after taking. However, such drugs can disrupt the functioning of the liver, kidneys, and heart, so long-term use is not recommended. The third group of drugs is hormonal. These are serious medications, which can only be prescribed by a doctor after examination and checking the patient’s hormonal status. In any case, if a person is subject to seasonal allergic manifestations, it is impossible to cure them completely. The most reasonable course of action is to contact an allergist and choose a therapy that will help you get through a difficult period with the least discomfort.