Some substances in the environment have a negative impact on the body because of the increased sensitivity to them of the immune system. As a result, allergic reactions occur, provoked by the production of specific antibodies (immunoglobulins E) on the penetration of stimuli into the blood, lymph and digestive tract.
Types of allergic reactions
In total, 4 types of described pathology are distinguished.
The first class includes anaphylactic allergic reactions of immediate type. They develop very quickly, within a few minutes or hours after contact with histamines.
The disease of this class is characterized by an increase in permeability and expansion of the walls of blood vessels, a reduction in smooth muscle tissue. This manifests itself in the following symptoms:
- hives;
- anaphylactic shock;
- attacks of bronchial asthma (atopic);
- spasms;
- false cereals;
- vasomotor rhinitis;
- swelling of the mucous membranes;
- allocation of a large amount of viscous mucus on the surface of bronchioles.
Also, acute allergic reactions cause a strong agonizing cough, runny nose, sneezing and lacrimation.
The second type of disease is called cytotoxic (cytolytic). It is provoked by the release of immunoglobulins not only of the E type, but also of G and M. Typical clinical manifestations are observed about 6 hours after exposure to stimuli, accompanied by the death of antigens in the human body and a decrease in their protective functions.
Usually, such an allergic reaction occurs on drugs and for certain diseases:
- Rhesus-conflict;
- hemolytic disease;
- thrombocytopenia ;
- hemolytic anemia.
Typically, this type of pathology affects newborns and infants up to 6 months, but it also occurs in adults.
Other types of allergic reactions are related to delayed hypersensitivity processes. They are associated with the entry into the inflammatory foci of various species of leukocyte cells that replace the damaged tissue with connective fibers.
Allergic reactions of delayed type
The third class of the disease is also caused by the production of immunoglobulins E, G and M.
The appearance of symptoms develops within 7-12 hours after the contact of a person with irritants from the external environment. A group of symptoms is called the reaction of immune complexes or the Arthus phenomenon.
The presented variety of allergy is typical for the following diseases:
- rheumatoid arthritis;
- dermatitis;
- systemic lupus erythematosus ;
- conjunctivitis;
- immunocomplex glomerulonephritis;
- serum sickness.
The latter type of allergic reactions is called late hypersensitivity, as it develops 25-72 hours after contact with histamines.
Observed symptoms:
- damage to the skin;
- inflammatory processes in the organs of the gastrointestinal tract;
- defeat of the respiratory tract.
It is worth noting that such signs are characteristic for the process of rejection of transplants after transplantation.
First aid for allergic reactions
First of all, it is necessary to exclude any possible contacts with irritants. With the development of puffiness of the respiratory tract and obstruction of air access, an antiallergic drug (intramuscular or intravenous) should be administered immediately.
Further therapy depends on what substance caused the symptoms, as well as the severity of clinical manifestations. Taking antihistamines should be followed until allergy signs disappear.