Dermatitis – a common name of various skin diseases. By dermatoses are inflammatory skin diseases, various skin dystrophies, benign and malignant tumors of the skin, etc. The reasons may be dermatosis exogenous (external) and endogenous (internal). External causes of dermatosis are described below. Mechanical agents – prolonged pressure, friction, bruises, etc. Physical agents – high and low temperature impact viruses, protozoa, vegetative bacteria – pathogenic fungi and animal parasites (ticks, bot, etc.), blood-sucking insects, which are the direct cause or a skin disease, or vector other infectious agents. Among the endogenous etiological factors should be noted common infectious diseases as acute (measles, scarlet fever, smallpox, etc.) and chronic (tuberculosis, etc.).
Often the cause of dermatosis metabolic disorders, lack of vitamins (A, C, PP, P, B complex, etc.), circulatory disorders resulting from functional or organic changes in blood vessels, as well as abnormalities in the endocrine secretion. An important role in the occurrence of dermatosis are organic and functional disorders especially of the peripheral and central nervous system. These endogenous factors are in some cases, direct etiologic agent of dermatosis, in others because of their violations caused by the normal physiological functions of the skin – only predisposing factors in the occurrence of skin lesions, other etiology. An example is the frequently observed furunculosis (staphylococcal infection) in patients with diabetes (disturbance of carbohydrate metabolism). Finally, we should bear in mind the possibility of hereditary transmission of certain dermatoses.