Allergy is a modified 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, vegetable, industrial origin. The body considers the ingress of antigens as a viral or infectious attack and produces a number of symptoms similar to SARS or the flu. In some cases, the development of an allergic reaction can threaten the patient's life. Sometimes the manifestations of the disease are completely harmless. Why does an allergy occur in adults? The most common causes are described in this article.
The reasons why some people are prone to allergies
Exposure to allergic reactions occurs in connection with the individual characteristics of the body. In some cases, heredity plays a role. As a factor providing a tendency to allergies, low immunity can be distinguished.
The genetic factor is most often transmitted through generation. For example, if a grandmother of a child suffered from hay fever, then with a probability of about 60% he will also begin to be allergic to pollen by the age of thirty to forty years. The intensity of the manifestations of such a reaction depends on the immune status and general state of health. Babies born to allergic parents may not suffer from manifestations of a painful reaction to the same provoking factors.
Why does a food allergy occur during pregnancy, and after childbirth passes without a trace, as if it had never been? Such a process does not arise due to genetics or due to a weakening of the immune system. The main factor that provokes the development of allergic reactions during pregnancy is a change in the response of cells of the immune system 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.
Allergic reaction
All types of disease, regardless of which antigen they appear on, proceed according to one mechanism. All symptoms appear in a strict sequence:
- 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, itching, urticaria, etc. At the immunological stage, the onset of the sensitization process proceeds.
- The pathochemical stage of the development of an allergic reaction. Those complexes that managed to form at the immunological stage attack mast cells containing granules that can activate inflammatory mediators. After this, activated mediators begin to penetrate into every corner of the body through the bloodstream. At this stage, pronounced signs already appear: lacrimation, skin itching, urticaria, etc.
- Pathophysiological stage. It is characterized by the fact that mediators, penetrated and entrenched in different tissues of the body, initiate allergic processes. Allergy is manifested in the form and to the extent that we are accustomed to notice it.
Allergy Classification
There are several types of reactions:
- Anaphylactic process. It is also called an immediate response to an allergen . Why does an allergy occur during the 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: skin itching, urticaria, anaphylactic shock, allergic rhinitis, Quincke's edema. 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 an allergy in the cytological process: thrombocytopenia, some types of toxic allergies.
- An immunocomplex allergic reaction in which antibodies of groups M and G are formed. They accumulate on the capillary walls. Subsequently, inevitably provoke their destruction. Representatives of the immune complex reaction: conjunctivitis, serum reactions, lupus erythematosus, urticaria, some types of dermatitis, hemorrhagic vasculitis.
Why is there a respiratory or respiratory allergy?
Why is pollen allergic? This is the so-called hay fever. An allergic reaction that belongs to the class of respiratory allergies. It occurs during the flowering period of wormwood, ragweed, poplar and other plants, which most often perceives human immunity as hostile to their life.
Due to the similarity of symptoms of hay fever, 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 some plants? Because the cells of the human immune system perceive pollen as a threat to the existence of the body.
Allergens are microscopic in size. It is not necessary to inhale poplar fluff - a tiny bit of poplar seed is enough to provoke the symptoms of hay fever. Patients make a common mistake - they think that if you stay in the room, then the manifestations of the disease will not overtake them. In fact, microscopic pathogens easily penetrate the room.
The most common aeroallergens that stimulate hay fever:
- pollen;
- spores of some fungi;
- dust mite;
- animal hair.
Why does skin allergy occur: dermatoses and urticaria
List of the most common manifestations of allergic reactions on the skin surface:
- itching (often so strong that the patient combs the epidermis to the blood);
- small red rashes, they are popularly called urticaria, 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 is there an allergy in children on the skin after they eat sweets? The fact is that most of these products are made using flavorings, colorings and preservatives. These components often cause the activation of immune cells, which perceive the entry into the blood of such substances as a threat to the life of the body. As a result, itchy rashes appear on the skin.
Causes of food allergies
Why is there an allergy to food? This is a rather complicated process.
Food intolerance in most cases occurs under the influence of two factors:
- Features of the allergen. Hyperreactivity is often caused by food antigens with high immunogenicity. They freely overcome the barriers of the digestive system. The highest concentration of them is in cow's milk, red vegetables, some varieties of fish, egg white, cereals, some fruits and nuts. Hypersensitivity of the cells of immunity to the components of these foods and causes rashes on the skin or itching.
- Genetic factors. Allergic manifestations on food products may occur due to an increase in the level of reactivity of immune cells. This process often occurs due to a genetic predisposition.
Allergic reactions to pets
An allergy often becomes an obstacle to a pet’s establishment. Already on the third or fourth day of cohabitation with a furry friend, intolerance to his coat occurs.
Why are you 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.
This problem can be solved quite simply: get a pet without hair. For example, an Egyptian cat.
List of the most unusual allergens
In some cases, antigens that provoke the occurrence of unwanted reactions are surprising in their diversity.
In a large percentage of patients, symptoms of the disease begin when interacting with the following allergens:
- sunlight;
- water;
- touch to metal;
- leaves of some trees.
Why is there an allergy to the sun? Rays of ultraviolet radiation are often perceived by the immune cells of allergy sufferers as a dangerous effect that can threaten life. Therefore, there is a rash, itching, swelling of tissues that have been exposed to sunlight. To prevent such a reaction, antihistamines should be taken.
Who is more likely to suffer from allergic reactions: men or women
Therapy of exacerbation of allergies in adults and children is carried out by an allergist or immunologist. These specialists may prescribe antihistamines that are ideal for each individual patient.
Statistical data, the information for which is collected from patients' appeals to allergists, reports that both men and women suffer from pollinosis approximately equally. But from the manifestations of reactions to taking medications, one and a half times more women suffer.
Methods for the diagnosis of allergic reactions
The following methods for detecting allergens are:
- taking blood for a quality test allows you to find out if there is a sensitization to this allergen;
- quantitative blood samples from the patient inform about the degree of sensitization.
Blood sampling for analysis is a standard method. A few drops of venous blood are enough for modern laboratories to detect the most likely allergen.
Effective directions for the treatment of allergic reactions
Most patients experience rather unusual manifestations of reactions - for example, an allergy to birch occurs. Why they are chasing the patient is not so important. After all, after a course of antihistamines, a person will forget about his problem for a long time.
There are three generations of antihistamines:
- the first generation - with antihistamine action (they are cheap, but provoke severe drowsiness);
- second generation - the most optimal drugs with a minimum of side effects;
- the third generation - the most modern and safe, but the high cost often becomes an obstacle for the patient to continuous therapy with such drugs.