Idiopathic urticaria is a common allergic dermatosis of a chronic course. Clinically manifested by severe itching and urticaria (flat-raised, palpable) rash, which persists on the skin for more than 6 weeks. Blisters have clear boundaries, sizes vary from 1.5 mm to 3-5 cm. A characteristic feature of the rash is its constant updating. The quality of life is impaired: itching, cosmetic defects lead to insomnia, social discomfort, functional disorders of the nervous system. The diagnosis is made on the basis of anamnesis, clinic, laboratory examination data. Treatment is carried out with second-generation antihistamines.
L50.1 Idiopathic urticaria
Idiopathic urticaria is a chronic urticarian dermatosis from the group of allergic diseases that occurs when many provoking factors are exposed to the skin. A distinctive feature of the pathology is the rash of itchy blisters, accompanied by angioedema of the surrounding tissues. Idiopathic urticaria occurs in 3% of the population, has no gender coloring, has no age, racial differences, is not endemic.
Urticaria is first found in the descriptions of Chinese doctors of the X century BC. It owes its modern name to Hippocrates, who in the 4th century BC noted the similarity of rashes after insect bites and rashes after contact with nettles. However, the term “urticaria” was widely used in 1796 by William Gallen. In 1823, astrologers suggested that urticaria be considered the result of a special arrangement of stars in the sky for each patient, in 1864, doctors for “women’s diseases” tried to associate it with menstruation. And only the discovery of mast cells containing histamine in 1879 by Paul Ehrlich led scientists to a modern understanding of the etiology and pathogenesis of urticaria. However, there is still no comprehensive knowledge on this issue.
The exact cause of the disease has not been established, idiopathic urticaria is called an etiologically heterogeneous disease. Provoking factors (triggers of the disease) can be food, medicines, chemicals, insect bites, hyperinsolation, hypothermia. Idiopathic urticaria accompanies as a symptom a number of somatic diseases (infections, systemic collagenoses, diabetes mellitus, malignant tumors).
Regardless of the cause that provoked urticaria, the leading role in the development of the disease is played by mast cells, which begin to secrete the vasoactive mediator histamine when damaged. In addition, the destruction of mast cells leads to the activation of prostaglandins – hormone-like substances involved in the development of inflammation. Cells of the immune system migrate to the site of the pathological focus, increasing the release of histamine into the dermis. Sometimes only an increase in the concentration of histamine in the skin is enough to form blistering elements of a rash, but more often autoimmune mechanisms are connected to the pathological process. Spontaneously, the immune system begins to produce autoantibodies to mast cell receptors, connecting with them and forcing mast cells to produce not only histamine, but also serotonin, which greatly enhances the clinical manifestations of idiopathic urticaria.
Idiopathic urticaria in modern dermatology is divided into three varieties:
- True allergic idiopathic urticaria – develops as a result of an allergic “antigen-antibody” reaction to a specific autoallergen.
- Pseudoallergic idiopathic urticaria – itchy blisters occur as a result of chemical or physical effects on the skin (frost, heat, light, sun, water).
- idiopathic urticaria – develops as a result of prolonged wearing of jewelry, wristwatches, belts containing chemical alloys or substances that cause skin allergization.
Symptoms of idiopathic urticaria
Symptoms may be of varying severity, but are always clinically manifested by a rash of itchy blisters, which are formed due to pinpoint edema of the papillary layer of the dermis as a result of changes in the permeability of the vascular wall. The skin around the blister is edematous (angioedema), the borders of the element are clear, the color ranges from bright pink to purple, the sizes vary. There is a constant sprinkling of primary elements that remain on the skin for six months or more, conquering more and more new areas of healthy skin. There is no typical localization.
The elements can merge with each other, resolve from the center of the blister. Itching causes scratching on the skin, excoriation appears, secondary infection may join. The quality of life is deteriorating dramatically. Itching, which does not disappear day or night, leads to insomnia, irritability, nervous breakdowns. Urticary rashes in open areas of the skin become aesthetic shortcomings of the patient, forcing him to lead an extremely closed lifestyle. Depending on the severity of the process, its prevalence, the patient experiences subjective sensations of varying intensity: weakness, headache, fever, weakness, chills, dyspeptic phenomena, stress.
Dermatologists and allergologists-immunologists diagnose idiopathic urticaria on the basis of the clinic and special testing, paying attention to itching and the duration of complete regression of blisters (more than 6 weeks on the skin with disappearance without a trace), as well as the presence of atopic dermatitis in the anamnesis. Due to the heterogeneity of the causes of the disease, the scope of diagnostic examination is quite wide. The medical standards include: blood test (eosinophilia), urine test, blood biochemistry (CRP, ALT, AST, total protein, bilirubin, blood sugar, thyroid hormones), rheumatic tests (antinuclear antibodies, cryoprecipitins), bacteriological and parasitological examination of feces; flora crops from foci of chronic infections; markers of viral hepatitis, HIV, Wasserman reaction.
Ultrasound of the abdominal cavity and EGDS with analysis for Helicobacter pylori is performed. Allergists use provocative tests for diagnosis: for example, they determine dermographism (a blister appears on the skin with a blunt object), cold and heat tests. If urticarian vasculitis is suspected, a skin biopsy is taken. Idiopathic urticaria is differentiated with urticular vasculitis, anaphylaxis, multiform, nodular, fixed erythema, pruritus, including pregnant women; bullous pemphigoid, parasitic invasion, paraneoplastic syndrome.
Idiopathic urticaria treatment
Patients suffering from idiopathic urticaria are shown a hypoallergenic diet with the exception of suspected food allergens; elimination of heat-cold triggers; exclusion of jewelry and accessories with unknown composition from everyday use; selection of photoprotective agents; careful analysis of medications taken.
Complex therapy includes medications that can reduce the sensitivity of the immune system: antihistamines (clemastine), filtrum sorbents), enzymes (pancreatin). This is enough for a mild form of the disease. If the process is localized on the face, glucocorticoids (prednisone) are attached. As background therapy, anti-inflammatory, antifungal, decongestant, sedative drugs are used; drugs that correct metabolic processes. To reduce the effect of mast cell mediators on target organs, to reduce degranulation, the drug omalizumab is recommended. Hormonal ointments are applied externally. There is evidence of the effective use of cytostatics and plasmapheresis in severe prolonged idiopathic urticaria (Quincke’s edema). The use of physiotherapy is reduced to UVI, UHF therapy, electrophoresis.
Prognosis and prevention
Patients with idiopathic urticaria should follow a number of simple rules: adhere to the diet prescribed by a dermatologist (and out of exacerbation), start hardening, do not neglect preventive measures in the influenza epidemic (masks, antiviral drugs, contacts at a minimum), use only hypoallergenic cosmetics, do not use chemical cleaning detergents, annually undergo a dispensary examination by a dermatologist, allergist-immunologist, dentist. The prognosis, given that the disease often resolves spontaneously, is generally favorable for life.