Urticaria – a disease manifested by a rash, the main element of which is blister, i.e. clearly limited skin swelling. The color of the blister is red, the diameter is from several millimeters to several centimeters.
Urticaria takes the third place in the structure of allergic diseases after bronchial asthma and drug allergies. 15-25% of the population in the course of a lifetime suffers hives or Quincke edema at least once.
The nature of skin lesions in case of urticaria is due to the peculiarity of the vascular network of the skin (“shock organ”). The main element of any type of urticaria is a blister, accompanied by itching and characterized by “volatility”, that is, the ability to disappear within a few hours or minutes. Such blisters have a red tint, rise above the skin, do not contain liquids in themselves. The area of their distribution can be different – from a small localization of the size of a coin to extensive lesions.
The acute form occurs immediately upon direct contact with an irritant or an allergen and disappears after a few hours. Perhaps a combination of acute urticaria and angioedema.
Chronic form persists for more than 6 weeks. It is often caused by non – immune mechanisms, including systemic diseases. Often (about 70% of cases) the cause of chronic urticaria remains unexplained.
It develops when exposed to cold. A common cause of cold urticaria is exposure to water or low temperature air. The reaction usually occurs within a few minutes after being in the cold. In severe cases, cold urticaria is accompanied by weakness, headache, dizziness, shortness of breath, heart palpitations. Abdominal pain and nausea may occur.
Reflex cold urticaria is a common or local reaction to cold. Sometimes it occurs only when cooling the entire body. Local reaction to the cold is manifested by a rash that occurs around the chilled area of the skin, while the skin that is in direct contact with the cold is not affected.
Occurs with severe or prolonged stress. In this case, symptomatic treatment brings only temporary relief, and during protracted stress it loses its effectiveness. To prevent chronization of the nervous urticaria, it is necessary to remove the source of stress, undergo a course of psychotherapy or relaxation activities.
This form occurs when skin or mucous membranes come into contact with certain substances. Characterized by blisters, itching, burning. The most common cause of contact urticaria is latex. In severe cases, a possible complication in the form of anaphylactic shock.
Dermographic (mechanical) urticaria – is a linear elevation and redness of the skin as a result of mechanical irritation (for example, belt pressure, vibration from a bike ride, etc.).
A form similar to it – urticaria from pressure – occurs 4-6 hours after compression of the skin (elastic stockings, shoes, etc.). There are two forms of urticaria from the effects of pressure – immediate and delayed. Immediate form – blisters and redness appear a few minutes after pressing on the skin (without friction and stretching). The rash is accompanied by burning sensation and lasts 30 minutes, but not more than 2 hours. Slow down form – dark, itchy and painful blisters appear on areas of the body that are prone to prolonged compression: after long walking, sitting. The rash appears between 30 minutes and 9 hours after skin irritation and lasts for about 36 hours. Perhaps indisposition, chills, headache.
Less common forms
Aqua urticaria is a rare form. Small bumps appear after contact with water at any temperature. In some cases, it may appear only itching without rash ( aquatic itching).
The urticaria of tension is provoked by an exercise stress; manifested in the form of a rash, vascular edema, wheezing, lowering blood pressure (hypotension).
Thermal urticaria. This form is characterized by small elevations (5-10 mm) above the skin, arising after overheating, baths, hot showers.
Solar urticaria. Occurs as a result of exposure to sunlight. It starts a few minutes after sun exposure; passes after 1-2 hours after sun exposure.
Idiopathic urticaria – the cause of which is unclear.
Diagnosis of acute urticaria is usually not difficult and can be done by a general practitioner or allergist-immunologist.
When reacting to a meal or medication, provocative tests are used with suspected allergens after the elimination diet.
Inhalation allergens – use skin tests, radio allergic test (PACT)
Idiopathic urticaria, which lasts for more than 6 weeks, involves the exclusion of systemic diseases (for this purpose, a skin biopsy, determination of ESR in the general blood test, urinalysis, ANAT, etc.)
Cold urticaria – cold sample: a piece of ice is placed on the skin for 5 minutes; observe the reaction for 10-15 minutes.
Thermal or exercise provoked urticaria: a test with exercise, a skin test with methacholine (local reaction to intradermal administration of 0.1 mg methacholine in 0.9% sodium chloride solution).
Solar urticaria – conduct solar irradiation of a certain wavelength. Delayed urticaria as a result of compression: put a bag of sand 2-4 kg for 3 hours.
Aqua urticaria – apply tap water of different temperatures.
Infectious urticaria – bacteriological examination of a pharyngeal swab, antistreptolysin titer , NGV, feces (for parasites), liver function tests, mononucleosis test.
Autoimmune urticaria – antinuclear antibodies (ANAT), complement, cryoglobulins , electrophoresis of serum proteins.
When treating acute urticaria, it is preferable to use antihistamines of the first generation — tavegil, suprastin (the effect of second-generation drugs is mainly manifested in later periods)
In the treatment of chronic forms used
loratadine 10 mg 1 time per day,
cetirizine 0.01 g once a day (in the evening) or 0.005 g 2 times a day (in the morning and in the evening)
or cyproheptadine 4-8 mg every 4-8 hours (for children – 0.25-0.5 mg / kg / day every 6-8 hours)
or fexofenadine ( telfast ) – 180 mg 1 time per day or ebastine for adults 10-20 mg 1 time per day, for children in the form of syrup,
in addition – cimetidine , ranitidine .
Improvement in urticaria occurs in less than 72 hours in 70% of patients. In the chronic form of improvement in the first day is observed in 30% of patients.
The factors provoking a urticaria are numerous. Here are some of them:
- Allergens: food, including food additives, drugs, poison of stinging insects, plant pollen, cosmetics, detergents, etc.
- Acetylsalicylic acid and other nonsteroidal anti-inflammatory drugs (ibuprofen, indomethacin , diclofenac, ortofen , etc.)
- Iodine – containing radiopaque substances
- Plasma substitutes (dextran solutions)
- Local anesthetics (lidocaine, novocaine, etc.)
- ACE inhibitors ( captopril , enalapril , etc.)
- Sodium thiopental
- Blood transfusion
- Physical factors: heat, cold, sun exposure, pressure, etc.
- Emotional stress
- Diseases in which urticaria is one of the syndromes
- Infections – viral (infectious mononucleosis, hepatitis), helminth infections
- Collagenoses (systemic lupus erythematosus, rheumatoid arthritis)
- Serum sickness
- Hyper – and hypothyroidism