Eczemas (dermatitis) caused by external factors are called contact eczemas. These substances that cause contact eczema are called irritants. In the acute phase, redness, swelling and vesicles are usually at the forefront, while in the chronic phase, dryness, crusting, thickening of the skin and cracks are at the forefront.
Simply contact eczemas;
Irritant contact eczemas.
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acute irritant contact eczema
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chronic irritant contact eczema
2- Allergic contact eczema
-acute allergic contact eczema
- chronic allergic contact eczema
3- Phototoxic, photoallergic contact eczema
Can be classified as.
Irritant Contact Eczema
One or more external factors are responsible. They initiate inflammatory reactions by stimulating some mediators without creating an immunological response in the skin. With constant and repetitive contact with irritants, tissue damage begins in the skin following inflammation. In addition to stinging, tingling, burning, a feeling of dryness and tightness occurs on the skin. Chemical burns occur in severe tissue damage caused by alkalis or acids. Irritant contact eczemas do not spread beyond the contact area.
Acute Irritant Contact Eczemas
It is the inflammation that occurs within 3-4 minutes as a result of single contact of an irritant or caustic chemical substance. Stinging, flushing, edema, vesicles, blisters and necrosis may occur. It can occur with many different irritants such as X-ray, ionizing radiation, organic solvents, lipid solvents such as carbon tetrachloride, mustard gas, tear gases, and herbal products.
Protective measures should be taken for people who deal with chemicals before treatment, although contact If it occurs, it should be washed quickly with plenty of water or cleaned with neutralizing agents. Then treatment should be done with wet dressings and closed dressings.
Chronic Irritant Contact Eczema
It occurs with repeated skin contact with low concentrations of non-damaging substances. Various chemical substances, physical traumas, dry skin due to low humidity, cold and heat, solvents, lubrication reducing substances (soap and detergents), drying powders, biological protective barrier as a result of constant exposure to water. The area disappears and sensitivity occurs on the skin. This type of eczema occurs most frequently in professional groups such as housewives, construction workers, hairdresser workers, hospital workers and motor mechanics. It begins with mild redness on the backs of the hands and forearms. Then, peeling and coarsening of the skin occur. Rarely, edema and watering occur. Continuous recurrence of chronic irritant eczema paves the way for allergic contact eczema. In the treatment, first of all, habits should be questioned and the factors that cause this eczema should be removed. During professional practices, non-irritating gloves with an inner lining made of cotton fabric should be used.
Allergic Contact Eczema
Antigen that occurs as a result of sensitization of the body with an allergen and then encountering the same allergen again. It is a series of clinical inflammatory reactions that occur with type-IV delayed hypersensitivity (cellular) in the skin due to antibody reaction.
Frequency of contact, predisposition of the person, presence of systemic diseases, constitutional factors such as dryness and atopy, systemic drugs used from person to person. It makes the clinic of allergic contact dermatitis different.
Mechanism of formation
In the 1st stage, the allergen enters the skin with contact sensitization. T-lymphocytes are enabled to recognize the allergen.
In the 2nd stage, it occurs when the substance comes into contact with the skin again. T-lymphocytes migrate to the contact area. Dermal inflammation occurs as a result of the resulting antigen-antibody reaction. This stage occurs in 24-48 hours.
It may turn into a generalized reaction when sensitized t-lymphocytes and allergens enter the circulation and reach other body parts. If the body is sensitized to this substance, the sensitivity continues for life.
Redness, swelling and vesicles occur within 24-48 hours following contact with the clinical allergen. Severe edema may occur in places where the tissue is loose, such as around the eyes. In the chronic period, symmetrically located, sharp-edged itching that flares up from time to time, thickening, crusting and dryness may be observed.
Substances that often cause allergic contact dermatitis
1. Metals: Nickel sulphate (ring, earring, necklace, coin, zipper, scissors), potassium dichromate (cement, printing material, polishes, dental prostheses), cobalt (ceramics, paint, varnish, hair dyes, detergents). r, paper and glass industry).
2. Preservatives: Parabens (cosmetic products, leather care products, make-up materials), formaldehyde (disinfectant, insecticide).
3. Fragrances ( Fragrances): Fragrance mixtures (soap, toothpaste, household cleaning products, perfume cologne), Peru balm (sweetener, chewing gum, chocolate, ice cream, wine, cough syrup, scented teas).
4.Latex( rubber) additives: Mercapto mixture, carba mixture, mercaptobenzothiazole, black rubber mixture. (gloves, syringes, cables, goggles, balloons and toys)
5.Plants:Primin , sesquiterpene, lactone mixture
6. Others (carriers and other cosmetic-pharmaceutical ingredients): Lanolin (topical moisturizing preparations and cosmetics), para-phenylenediamine (hair dyes, fur dyes, temporary tattoos and inks).
Diagnosis: A detailed history should be taken, habits, hobbies and substances with which the lesion comes into contact should be questioned. It is important to determine the place where the first lesion begins. Paying attention to the location and shape of the lesion gives us clues (such as patch allergy). If it is at the level of the scalp, the hair dyes are in the ear. Nickel allergy due to earrings, redness and watering around the wound may be due to the medication used. Therefore, a detailed physical examination is very important.
Patch test is a test based on the principle of creating a reaction by contact with the skin with known standard allergens. Identified allergen. It is done with a series of series. It supports the patient's history and helps to show when the patient is sensitive to many substances that he does not know but comes into contact with. The specificity of this test has been found to be 70%. It is the most commonly used European standard patch test series. If no results are obtained in these, more specific tests such as dental, medication, and shoes are used. Tests can be started. Items attached to the back like a tape can be opened after 48 hours.
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