Allergic urticaria

Urticaria is a disease manifested by erythematous itchy elements that rise above the surface of the skin and, as a rule, become more intense during eruptions. Urticaria or urticaria, from the Latin word urtica - nettle, is a disease of the skin in the form of small erythematous rashes. The rash is accompanied by itching and is most often provoked by allergies. The name "hives" of the rash was obtained due to visual similarity to the blisters remaining after contact with the nettle. As a symptom, urticaria is not a specific sign, as it can be a manifestation of both an allergic reaction and another disease.

Approximately 10-20% of people had hives at least once in their lives. Hives and angioedema often develop in girls.

Approximately 15-20% of children suffer hives at least once. In most cases, urticaria has an easy course, but it can pass into a more severe generalized form, which in exceptional cases leads to anaphylactic shock or laryngeal edema. Urticaria can cause obstruction of the upper respiratory tract, threatening the life of the patient. The leading mechanism of urticaria development is a reactive mechanism of damage. With blood transfusions, the second type of injury mechanism can be included; with the introduction of a number of drugs, antitoxic serums, gamma globulins - an immunocomplex mechanism of damage.

[1], [2], [3], [4], [5], [6], [7], [8], [9]

Causes of the allergic urticaria

Causes of urticaria

Acute hives in 90% of cases is a consequence of one or another type of allergy. The mechanism of the formation of acute urticaria is based on the synthesis of specific immunoglobulins - antibodies IgE. More often, urticaria provokes the following factors: 

• Drugs - a group of penicillins, sulfonamides, non-steroidal anti-inflammatory drugs, glucocorticosteroids, diuretics and many others.
• Food ingredients - products containing protein, tyramine, salicylates, pollen.
• Insect bites.
• Other reasons that provoke hives contact way - latex, gasoline, rubber, metal.
• Acute viral infections.
• Hormonal dysfunction.

It should be noted that the above reasons provoke the most often acute form of urticaria, chronic urticaria is considered idiopathic, that is, a disease of unclear etiology. Allergists put forward the hypothesis that idiopathic urticaria can be caused by autoimmune, endocrine diseases, but this theory still needs statistical confirmation.

[10], [11], [12], [13], [14], [15]

Symptoms of the allergic urticaria

Symptoms of urticaria

The main symptoms of hives are the following symptoms: 

• Small rashes, similar to blisters. The rash may look like small areas of reddened skin (erythema) or localized fused blisters.
• A characteristic itch, which can start without an obvious rash.
• Lack of pain (blisters painless).
• Typical short-term eruptions, which are, as a rule, after a day, leaving no trace. Blisters that begin to peel off a day later, or ulcerate, indicate another disease.
• The rash can develop intensively, right up to the Quincke's edema.

Description of the rash with hives is the basic information for the diagnosis of the disease. The rash can be located symmetrically with cholinergic urticaria, but more often the rashes are asymmetrically distributed, they can be in the form of single chaotic blisters, but sometimes merge into a continuous angioedema, which is defined as a Quincke's edema. Blisters have a pale pink, slightly reddish hue and appear in any part of the body. Quincke's edema is characterized by localization on the face, when the rash spreads through the eyelids, lips, puffiness affects the tongue and throat and only then spreads over the hands and feet. Urticaria is rarely accompanied by hyperthermia, if the body temperature rises, this indicates the presence of a concomitant inflammatory infection. Statistics state that half of patients with urticaria are diagnosed as an isolated symptom that does not flow into the angioedema, but in the second half Quincke's swelling is very often developed very quickly.

Hives of allergic origin are not contagious in themselves and are not transmitted by contact or by airborne droplets. However, urticaria can be a symptom of an infectious and not allergic disease, then the patient is a source of possible contamination of others.

It should be noted that the hives on symptoms can be similar to manifestations of other diseases. Among them the most common are the following: 

1. Systemic or dermal mastocytosis (pigmentary urticaria) - diffuse infiltration of the skin, beginning with the appearance of small blisters.
2. Urticary vasculitis, which, unlike classical urticaria, lasts from 3 to 7 days. 
3. Drug rash - an allergy to contact with external medicines.
4. Atopic dermatitis (allergic dermatitis).
5. Scabies - acarodermatitis caused by a tick.
6. Anaphylactoid purpura - capillarotoxicosis, hemorrhagic disease.
7. Contact dermatitis is an allergic skin reaction in a delayed type.
8. Multiform erythema - exudative rashes.

Forms

Types of urticaria

Urticaria is divided into two main categories according to the type of disease: 

1. Chronic urticaria. It is believed that if urticaria lasts more than six weeks, it has a chronic form. 
2. Acute hives last for several hours or days. The total duration does not exceed six weeks.

Chronic urticaria in clinical practice is most often found in women, acute form - in children and adolescents in the puberty period. Allergists say that the acute form of urticaria does not need serious treatment, because it passes on its own, provided it is clearly diagnosed. However, in 10% of allergy sufferers there is a transition of the acute form to a chronic one, when the therapy can be quite long, nevertheless, after 6-8 months, 100% complete recovery occurs.

In addition to forms, urticaria is divided into different species, among which the most often diagnosed physical urticaria (mechanical). This type of rash is associated with the effect on the skin of various stimuli: 

• A household cause of a mechanical nature is squeezing and rubbing with uncomfortable clothing, an object (urticaria of pressure, dermographic urticaria); 
• The impact of solar radiation - solar urticaria; 
• Effects of water - aquatic urticaria; 
• Psycho-emotional impact, stress, exacerbated by stuffiness; dry air in the room - cholinergic urticaria; 
• Effects of heat - thermal urticaria; 
• The effect of cold is cold urticaria.
• Insect bites, skin contact with external medicines - papular or contact urticaria.

The most rare subspecies are vibrational (when subjected to constant vibration, for example, from an industrial, industrial device).

Description of urticaria 

1. Dermographic subtype of urticaria, which is called urticaria dermographism. Such urticaria is a form of mechanical rash and is provoked by friction or irritation of the skin. The reason may be uncomfortable clothing, an object that a person by virtue of his profession is forced to apply constantly. 
2. Solar urticaria, which manifests itself as a reaction to excessive tanning or simply because of the intolerance of ultraviolet radiation. 
3. A very rare form of urticaria - aquatic, which is provoked by contact with any water, is manifested by severe itching and erythematous rashes. 4.
4. Cholinergic appearance, which is the result of excessive sweating. Activation of sweat secretion in turn is provoked by a psychoemotional factor, which causes a typical vegetative reaction. The human body temperature can rise by several degrees without apparent inflammatory causes. Less often the cholinergic urticaria appears after being in a very stuffy, hot room or because of physical overstrain. This kind of urticaria is manifested by diffuse multiple eruptions throughout the body and quite often ends with Quincke's edema.
5. Cold urticaria, which was also considered until recently a rare allergic appearance. Today, every tenth allergic person suffers from cold urticaria, evidently due to the general allergon of the body. Provoke cold reaction can not only the external effects of cold air, but also the use of cold drinks, food and even a touch to a cold object. 
6. Thermal urticaria looks like a cold, but provokes its contact with warm air or the use of hot dishes and drinks. This type of rash is extremely rare.
7. Mastocytosis or pigmentary urticaria is an autoimmune disease in which excessive amounts of mast cells (cells) accumulate in the tissues.
8. Papular urticaria is a contact form, provoked by small insects that bite the skin of a person. The rash is very characteristic and manifests itself in the form of small nodules - papules.

Also, urticaria has obscure, poorly studied species, which include neuropsychiatric, more similar to the cholinergic species, there is a recurrent urticaria, idiopathic urticaria are types of disease with an unknown etiology.

[16], [17], [18]

Complications and consequences

How dangerous is urticaria?

The most dangerous consequence of urticaria is angioedema, that is, Quincke's edema, which can develop under the condition of an acute form of the allergic disease. However, in allergological practice, such cases are very rare. All other types of urticaria are absolutely not dangerous and do not pose a threat to the life of the patient. The only unpleasant symptom is a strong, incessant itching. More often the urticaria proceeds in an acute form and passes during the day, a maximum of a week. Rarely acute urticaria lasts for more than a month, this happens when the rash is provoked by an infectious disease. As soon as the original cause is eliminated, the itching and blisters go away. The chronic form of urticaria is more uncomfortable, but also does not threaten with serious complications.

Treatment of the allergic urticaria

Treatment of urticaria

Therapeutic measures that help to cure urticaria, are primarily aimed at neutralizing the cause of the disease. That is why differential diagnosis of hives is so important as a sign. If the main allergen is found out, the first stage of therapy is elimination (restriction of contact, an exception from a diet) provoking trigger. If urticaria is caused by an infection, antibiotic therapy is performed. Further treatment of urticaria, as a rule, differs little from the standard scheme of treatment of an allergy and consists in the appointment of the following drugs: 

1. Antihistamines that affect the receptors of histamine (H1 receptors or H2 receptors). These drugs effectively relieve the itching and other uncomfortable manifestations of hives. 
2. Immunomodulating drugs are most often indicated in the chronic form of urticaria. 
3. If urticaria is accompanied by bronchospasm, antileukotriene drugs that stop asthmatic attacks may be prescribed.

Edema Quincke suggests an ambulance. As a rule, it is neutralized by the immediate administration of epinephrine (adrenaline).

Hives in any form and any kind requires compliance with a hypoallergenic diet, even if not caused by a food provoker. All foods containing tyramine - hard cheeses, red wine, liver, dry sausage, beans, beer are excluded from the diet. It is also necessary to abandon all types of citrus, cocoa, chocolate, nuts and honey, to limit the consumption of chicken eggs. The diet should be observed for at least three weeks, the further menu depends on the dynamics of the disease and the improvement of the condition.