What is Dermatitis?
The term “dermatitis” refers to the inflammatory process in the skin, which is formed as a result of the direct action of external stimuli of physical (heat, light, radiant energy) or chemical (caustic substances, acids, alkalis) origin.
Causes of Dermatitis
Physical irritants include the following main factors:
- mechanical, most often simple pressure or friction;
- temperature agents.
Here, the effects of high (burns) and low (chills, frostbite) temperatures stand out separately:
- solar energy, especially ultraviolet and infrared radiation;
- ionizing radiation, which mainly includes x-ray and radioactive radiation.
The group of chemical irritants, in turn, includes:
- salts of certain types of acids;
- high concentration disinfection medicines.
The entire list is far from being limited to these substances, but here is the main set of tools that an ordinary person has to face in everyday life.
In addition, another classification of irritants that cause the development of dermatitis is very important for understanding the causes of the development of the disease and its manifestations, according to which they are divided into conditional and unconditioned according to the nature of their interaction with the body.
Conditional irritants are also called allergens. The difference between these groups is quite simple.
Unconditional irritants, also called obligate, are called so because in any person, under any conditions, they can cause the development of allergic reactions in the skin and dermatitis. This includes strong solutions of alkalis and acids, water with a temperature of more than 60 ° C. Irritants from the conditional group are capable of causing allergic reactions and dermatitis only in a rather limited group of so-called sensitive, or susceptible, people. Quite often, such patients have other concomitant types of allergies.
Pathogenesis during Dermatitis
Dermatitis resulting from the action of unconditioned irritants is called simple, sometimes artificial, or artifact. The disease caused by conditioned stimuli is usually called allergic, since these stimuli themselves are also called allergens.
There is also a special kind of dermatitis that does not fit into the above classification. This is the so-called toxicoderma group. A distinctive feature of this variety is that dermatitis does not develop after application of the irritant to the skin, but after ingestion, through the digestive tract or as a result of its introduction into a vein or muscle (various medicinal substances), by inhalation of vapors (irritant enters the skin through blood from the respiratory tract). Moreover, all stimuli are conditional, that is, they cause disease only in individuals predisposed to them.
And finally, there is another big classification, according to which dermatitis is divided into drug and allergic. This classification includes only some types of dermatitis and is used only in hospitals. Drug dermatitis occurs as a result of the action on the skin of large concentrations of drugs. Allergic forms of dermatitis develop most often in medical workers who have direct frequent contact with certain medications (antibiotics, especially streptomycin; chlorpromazine). This type of dermatitis is also called sometimes professional medication. A very common phenomenon is the so-called fixed type of drug dermatitis. At the same time, when taking the same drug that can cause illness, skin rashes always occur in the same places. Most often, the medical variety of dermatitis develops as a result of taking drugs such as penicillin (as, incidentally, all other antibiotics from the penicillin group, which are the most allergenic antibacterial drugs), streptomycin, and other antibiotics.
Despite the very different origin of different types of dermatitis, all of them are based on the same allergic reactions that develop on different irritants. Therefore, the main directions in the treatment of dermatitis will be the same.
Topical drugs are drugs that are applied directly to the site of the lesion and inhibit the local inflammatory process. This group of drugs is perhaps the most important in the treatment of dermatitis. In all cases when the disease proceeds in a mild form, only external drugs are used. Their advantage is that they almost never have side effects and contraindications, often turn out to be more effective than drugs of other pharmacological groups.
Most often with dermatitis in clinical practice, salicylic ointments are used, which have a not very pronounced anti-inflammatory effect. In more severe forms of the disease, drugs are used that contain substances that are more active in this regard, which include tar, naphthalene, and adrenal cortex drugs.