Allergy is an altered reaction of the human immune system to certain substances. In medicine, they are called allergens or antigens. This is an extensive group of active components of household, animal, plant, and industrial origin. The body regards the ingress of antigens as a viral or infectious attack and produces a number of symptoms similar to SARS or influenza. In some cases, the development of an allergic reaction can threaten the patient's life. Sometimes the manifestations of the disease are quite harmless. Why do adults develop allergies? The most common causes are described in this article.
Reasons why some people are prone to developing allergies
Susceptibility to allergic reactions occurs due to the individual characteristics of the body. In some cases, heredity plays a role. Low immunity can be identified as a factor providing a tendency to allergies.
The genetic factor is most often passed down through the generation. For example, ifthe child’s grandmother suffered from hay fever, then with a probability of about 60% he will also become allergic to pollen by the age of thirty or forty. The intensity of the manifestations of such a reaction depends on the immune status and general he alth. Babies born to allergic parents may not suffer from a painful reaction to the same triggers.
Why do food allergies occur during pregnancy, and after childbirth disappear without a trace, as if it never happened? This process does not occur because of genetics and not because of the weakening of the immune system. The main factor that provokes the development of allergic reactions during pregnancy is a change in the reaction of immune system cells to so-called antigens. They act as antigens and are found in most foods that cause itching, hives, nausea and other manifestations of the disease.
Development of an allergic reaction
All types of disease, regardless of what antigen they are manifested on, proceed according to the same mechanism. All symptoms appear in a strict order:
- Immunological stage. It is characterized primarily by the fact that the body begins to produce class E immunoglobulin to the allergen. This process subsequently causes the appearance of a type of reaction - tearing, pruritus, urticaria, etc. At the immunological stage, the beginning of the sensitization process takes place.
- Patochemical stage in the development of an allergic reaction. Thosecomplexes that have been formed at the immunological stage attack mast cells containing granules that can activate inflammatory mediators. After that, activated mediators begin to penetrate into every corner of the body through the bloodstream. At this stage, pronounced signs already appear: tearing, itching, urticaria, etc.
- Pathophysiological stage. It is characterized by the fact that mediators that have penetrated and entrenched in different tissues of the body initiate allergic processes. Allergy manifests itself in the form and degree in which we are accustomed to noticing it.
Classification of allergies
There are several types of reactions:
- Anaphylactic process. It is also called an immediate allergen reaction. Why does an allergy occur during an anaphylactic process? The interaction of antibodies (E, G) and immunoglobulins stimulates the production of histamine. It causes the development of allergies. The main representatives of reactions of this type: pruritus, urticaria, anaphylactic shock, allergic rhinitis, Quincke's edema. The anaphylactic process can occur both in the body of an adult and a child.
- Cytotoxic process. Antigens of groups M and G suppress membrane antigens. This is the process of cytolysis. Representatives of allergies in the cytological process: thrombocytopenia, some types of toxic allergies.
- An immune complex allergic reaction in which antibodies of groups M and G are formed. They accumulate on the capillary walls. Subsequently, they inevitably provoke their destruction. Representatives of the immune complex reaction: conjunctivitis, serum reactions, lupus erythematosus, urticaria, some types of dermatitis, hemorrhagic vasculitis.
Why do respiratory or respiratory allergies occur
Why do pollen allergies happen? This is the so-called pollinosis. An allergic reaction, which belongs to the class of respiratory allergies. It occurs during the flowering period of wormwood, ragweed, poplar and other plants, which most often the human immune system perceives as hostile to its life.
Due to the similarity of hay fever symptoms, many patients confuse the first manifestations of the disease with bronchitis, tuberculosis and other infectious and inflammatory diseases of the respiratory system. Why is there an allergy to the flowering of certain plants? Because the cells of the human immune system perceive pollen as a threat to the existence of the organism.
Allergens are microscopic. It is not necessary to inhale poplar fluff - a tiny fraction of a poplar seed is enough to provoke symptoms of hay fever. Patients make a common mistake - they think that if they stay in the room, then the manifestations of the disease will not overtake them. In fact, microscopic causative agents of the reaction easily enter the room.
The most common aeroallergens that cause hay fever:
- pollen;
- spores of some mushrooms;
- dust mite;
- woolanimals.
Why skin allergies occur: dermatoses and urticaria
List of the most common manifestations of allergic reactions on the surface of the skin:
- itching (often so severe that the patient scratches the epidermis until it bleeds);
- small red rashes, popularly called hives, and in the medical world - dermatitis;
- papules - rashes of a relatively large size (up to two mm in diameter) white;
- purulent rashes - are formed relatively rarely, most often when exposed to chemical allergens on the surface of the epidermis.
Why do children develop skin allergies after they eat sweets? The fact is that most of these products are produced using flavorings, dyes and preservatives. These components often cause the activation of immune cells, which perceive the entry of such substances into the blood as a threat to the life of the body. As a result, itchy rashes appear on the skin.
Causes of food allergies
Why do food allergies occur? This is a rather complex process.
Food intolerance in most cases occurs under the influence of two factors:
- Features of the allergen. Hyperreactivity is more often caused by food antigens with high immunogenicity. They freely overcome the barriers of the digestive system. Their concentration is highest in cow'smilk, red vegetables, some types of fish, egg whites, cereals, some fruits and nuts. Hypersensitivity of immune cells to the components of these foods and causes skin rashes or itching.
- Genetic factors. Allergic manifestations to food products may occur due to an increase in the level of reactivity of immune cells. This process often occurs due to genetic predisposition.
Allergic reactions to pets
Allergies often become an obstacle to getting a pet. Already on the third or fourth day of cohabitation with a furry friend, intolerance to his coat appears.
Why do you get allergic to cats or dogs? Most often, the reason is that microscopic scraps of animal hair settle on the mucous membrane of the respiratory tract.
The solution to this problem can be quite simple: get a pet without hair. For example, an Egyptian cat.
List of the most unusual allergens
In some cases, the antigens that provoke unwanted reactions are surprising in their diversity.
A large percentage of patients develop symptoms when exposed to the following allergens:
- sunshine;
- water;
- metal touch;
- leaves of some trees.
Why do people get allergic to the sun? Ultraviolet rays are often perceived by the immune cells of allergic people as a dangerous effect that can threaten life. Sothere is a rash, itching, swelling of tissues that have been exposed to sunlight. Antihistamines should be taken to prevent this reaction.
Who is more likely to suffer from allergic reactions: men or women
Therapy of exacerbation of allergies in adults and children is handled by an allergist or immunologist. These specialists can prescribe antihistamines that are ideal for each individual patient.
Statistical data, for which information is collected from patients' allergists, report that pollinosis affects approximately equally men and women. But one and a half times more women suffer from manifestations of reactions to taking medications.
Methods for diagnosing allergic reactions
There are the following methods for detecting allergens:
- taking blood for a qualitative sample allows you to find out if there is a sensitization to this allergen;
- quantitative blood samples from a patient inform the degree of sensitization.
Blood is taken for analysis by the standard method. Modern laboratories only need a few drops of venous blood to detect the most likely allergen.
Effective directions for the treatment of allergic reactions
Most patients experience rather unusual manifestations of reactions - for example, there is an allergy to birch. Why they persecute the patient is not so important. After all, aftera course of antihistamines, a person will forget about his problem for a long time.
There are three generations of antihistamine medicines:
- first generation - with antihistamine action (cheap, but provoke severe drowsiness);
- second generation - the most optimal drugs with a minimum of side effects;
- third generation - the most modern and safe, but the high cost often becomes an obstacle for the patient to continuous therapy with such drugs.
