Urticaria is a skin disorder that causes blistering and / or angioedema . Urticaria is characterized by the rapid appearance of flat, pale pink, highly itchy blisters raised above the skin , which in their appearance and manifestations are very similar to burns caused by nettles (hence the name). Blisters can coalesce, engulfing large areas of the skin. In this case, usually the defeat is symmetrical. The appearance of blisters is associated with the release of biologically active substances in the body, which cause vascular edema of tissues around the body. Therefore, urticaria is characterized by the same rapid disappearance of blisters, without any traces or even hyperpigmentation. According to statistics, a third of all people have had hives at least once in their lives.
Taking into account the duration and etiological factors causing urticaria, the disease is subdivided:
- Acute (duration up to 6 weeks).
- Chronic (lasting more than 6 weeks).
By etiological factor:
- Spontaneous ( idiopathic ).
- Pressure urticaria (delayed pressure urticaria).
- Heat-induced urticaria (heat).
- Solar urticaria.
- Symptomatic urticarial dermographism.
- Vibration angioedema (vibration urticaria / angioedema ).
- Other types of urticaria: aquagenic ; cholinergic; contact.
In most cases, acute urticaria is of an allergic nature (often medicinal). Drugs that cause urticaria include aspirin and other non-steroidal anti-inflammatory drugs, antihyotensin – converting enzyme inhibitors , antibacterial drugs, etc. Food products (citrus, chocolate, nuts, eggs, etc.), food additives ( glutamate , dyes, stabilizers , preservatives).
The reason for the development of chronic urticaria can be various infectious diseases (helminthiasis, foci of focal infection, viral hepatitis). A number of concomitant diseases and conditions can also lead to the appearance of urticaria . These include chronic diseases of the gastrointestinal tract (biliary dyskinesia, chronic gastritis and peptic ulcer disease associated with Helicobacter pilori , etc.), endocrine pathology (diabetes mellitus, autoimmune thyroiditis, etc.), oncological diseases (including, leukemia, Hodgkin’s and non-Hodgkin ‘s lymphomas), diffuse connective tissue diseases (systemic lupus erythematosus, dermatomyositis), cryoglobulinemia , abnormal pregnancy, menopause. In some cases, the appearance of blisters is provoked by physical effects on the skin (high and low temperatures, friction, pressure changes, etc.) and various substances that enter by inhalation (household dust, animal hair, pollen, etc.), insect bites.
In the presence of chronic urticaria, the patient must be examined for the presence of specific IgE antibodies , it is also necessary to be examined for the presence of diseases of the gastrointestinal tract, liver and the presence of parasites. In the etiology of chronic urticaria, a hereditary and neurogenic factor often plays a major role.
However, in almost 30% of patients, the cause of urticaria cannot be identified.
The diagnosis of urticaria is based on the characteristic clinical presentation, including the history. In the general analysis of blood, eosinophilia is characteristic . In order to detect the presence of specific sensitization (the appearance of urticaria upon contact with specific allergens), allergological tests and a blood test for the content of specific IgE antibodies are carried out . An examination is carried out for the presence of intestinal dysbiosis.
To prove other types of urticaria (physical factors), provocative tests are used that mimic the factors that caused the reaction. Cold test – applying a piece of ice to the skin; vibration urticaria – test with a vibrator; aquagenic subtype – applying a water compress for 20 minutes or using wet clothes; cholinergic urticaria – taking a hot bath, eating spicy foods; delayed urticaria from pressure – test with pressure and determination of the sensitivity threshold; thermal – thermal provocative test and determination of the sensitivity threshold; solar urticaria – ultraviolet and visible light of different wavelengths and determination of the sensitivity threshold; symptomatic dermographism – mechanical action (for example, applying strokes with a spatula) and determining the sensitivity threshold; contact urticaria – skin provocative tests ( prick / patch tests).
In the clinical analysis of blood (leukocyte formula, ESR), eosinophilia is possible .
From biochemical analyzes, the definition of C-reactive protein is prescribed to assess the inflammatory response. In differential diagnosis with mastocytosis, the determination of tryptase in the blood serum is prescribed .
Instrumental diagnostic methods (in addition to provocative tests) are prescribed by the attending physician if it is necessary to carry out differential diagnostics or to monitor concomitant diseases.
Differential diagnosis is carried urticaria diseases which are accompanied urticarial eruptions – urticarial vasculitis, urticaria pigmentosa, bullous pemphigoid , polymorphic erythema, Lyme disease, systemic lupus erythematosus, polymorphous rash pregnant, autoimmune progesterone dermatitis kriopirin -associated syndromes, syndrome Schnitzler , acute febrile neutrophilic dermatosis (Sweet’s syndrome), systemic mastocytosis , mast cell monoclonal activation syndrome , carcinoid syndrome.
The main laboratory tests used (including provocative tests):
- Clinical blood test (complete blood count, leukocyte count, ESR) An increase in the content of eosinophils is revealed.
- Allergic studies, determination of the content of IgE antibodies . With the help of this study, it is possible to identify the presence of allergens of various origins (food, chemical compounds, pharmacological compounds) in the blood serum.
- Study of feces for protozoa and helminth eggs.
- Tryptase (differential diagnosis with mastocytosis ), there is an increase in mastocytosis .
- Provocative tests (physical urticaria) to confirm the factor that caused the reaction: test with a vibrator; wet clothing test ( aquagenic urticaria); cold test and others.