Allergic urticaria

Urticaria is a disease that manifests itself in erythematous itchy elements that rise above the skin surface and, as a rule, intensify when scratching. Urticaria, or urticaria, from the Latin word urtica - nettle, is a skin disease in the form of small erythematous rashes. The rash is accompanied by itching and is most often provoked by an allergy. The name "urticaria" rash received due to the visual similarity to the blisters that remain after contact with nettles. As a symptom, urticaria is not a specific sign, since it can be a manifestation of both an allergic reaction and another disease.

About 10-20% of people have had urticaria at least once in their lives. Urticaria and angioedema are more common in girls.

Approximately 15-20% of children suffer from urticaria at least once. In most cases, urticaria has a mild course, but it can develop 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 the reaginic mechanism of damage. During blood transfusions, type II of the damage mechanism can be activated; when a number of drugs, antitoxic serums, gamma globulins are administered - the immune complex mechanism of damage.

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Epidemiology

The epidemiology of urticaria is important to understand the prevalence and impact of this condition on the population. Urticaria can occur at any age, although it is most common in adults, especially women. Key aspects of urticaria epidemiology include:

Prevalence

• Overall prevalence: Urticaria occurs in approximately 15-20% of the population during their lifetime.
• Age and gender: Hives most often affect young adults, especially women. Women are affected by the condition about twice as often as men.

Geographical and ethnic features

• Geographic variations: The prevalence of urticaria may vary depending on geographic location and climate.
• Ethnic factors: There is evidence of differences in the prevalence and nature of the disease among different ethnic groups, but this requires further study.

Causes urticaria

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

• Medicinal preparations – penicillin group, sulfonamides, non-steroidal anti-inflammatory drugs, glucocorticosteroids, diuretics and many others.
• Food ingredients – products containing protein, tyramine, salicylates, pollen.
• Insect bites.
• Other causes that provoke urticaria by contact are latex, gasoline, rubber, metal.
• Acute viral infections.
• Hormonal dysfunctions.

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

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Risk factors

Here are some of the main risk factors for hives:

1. Allergic reactions

• Food allergens: Certain foods, such as nuts, seafood, eggs, and dairy products, can cause an allergic reaction that results in hives.
• Medications: Aspirin, ibuprofen, and some antibiotics (especially penicillins) can trigger hives in sensitive people.
• Insect bites and pollen: Bee, wasp or ant stings, as well as exposure to pollen, can cause an allergic reaction.

2. Infections

• Viral infections: Colds, flu, and other viral infections are often associated with the appearance of hives.
• Bacterial infections: Certain bacterial infections, including urinary tract infections and streptococcal infections, can also contribute to the development of urticaria.

3. Physical factors

• Physical urticaria: Some people may develop hives in response to physical stimuli such as pressure, cold, heat, sunlight, or sweating.

4. Stress and emotional factors

• Psychological stress: Severe stress and emotional tension can worsen the symptoms of hives or contribute to their occurrence.

5. Chronic diseases

• Autoimmune diseases: Hives may be associated with some autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis.
• Chronic infections: For example, chronic helicobacter pylori infection may be associated with chronic urticaria.

6. Genetic factors

• Family history: Having close relatives with hives may increase your risk of developing it.

Given the variety of risk factors, it is important to take a comprehensive approach to diagnosing and treating urticaria. In some cases, it may be necessary to consult with an allergist or dermatologist to identify specific causes and develop an effective treatment plan. It is always recommended to avoid known triggers if they have been identified.

Pathogenesis

The pathogenesis of urticaria includes several key mechanisms that lead to the development of the characteristic symptoms of this disease. Urticaria is based on a reaction associated with the release of inflammatory mediators, in particular, histamine, from mast cells of the skin. Here are the main aspects of the pathogenesis of urticaria:

Release of histamine and other mediators

1. Mast cells and basophils: These cells contain granules with histamine and other inflammatory mediators. When activated, they release these substances into the tissue.
2. Histamine: The main mediator that causes dilation of blood vessels (vasodilation) and increased permeability, which leads to swelling and redness of the skin.

Allergic and non-allergic pathogenesis

• Allergic urticaria: occurs when the immune system reacts to an allergen, resulting in the activation of mast cells via immunoglobulin E (IgE).
• Non-allergic urticaria: can be caused by physical factors, drugs, infections and other non-immune mechanisms.

Autoimmune factors

• Autoimmune urticaria: In some cases, antibodies can attack the body's own mast cells, causing them to degranulate without the presence of an external allergen.

Physical causes

• Physical urticaria: Some forms of urticaria may be triggered by physical stimuli such as cold, heat, pressure, vibration, or sun radiation.

Neurogenic mechanisms

• Stress and emotional factors: Psychological stress may worsen urticaria, although the exact mechanisms by which stress affects mast cells are not fully understood.

Effect of drugs

• Nonsteroidal anti-inflammatory drugs (NSAIDs): Some medications, especially NSAIDs, can cause or worsen urticaria by affecting arachidonic acid metabolism.

The pathogenesis of urticaria is complex and multifactorial, which explains the diversity of clinical manifestations and responses to treatment. Understanding these mechanisms is important for the development of effective therapeutic strategies and management of urticaria symptoms.

Symptoms urticaria

The main symptoms of urticaria are the following signs:

• Small, blister-like lesions. The rash may appear as small areas of reddened skin (erythema) or as localized, coalesced blisters.
• Characteristic itching that may start without an obvious rash.
• No pain (blisters are painless).
• The characteristic short-term nature of the rash, which usually disappears within a day, leaving no trace. Blisters that begin to peel or ulcerate after a day indicate another disease.
• The rash can develop intensively, up to Quincke's edema.

Description of the rash in urticaria is fundamental information for diagnosing the disease. The rash can be located symmetrically in cholinergic urticaria, but most often the rash is located asymmetrically, can be in the form of single chaotic blisters, but sometimes merge into a continuous angioedema, which is defined as Quincke's edema. Blisters have a pale pink, slightly reddish hue and appear on any part of the body. Quincke's edema is characterized by localization on the face, when the rash spreads over the eyelids, lips, swelling affects the tongue and larynx and only then spreads to 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 show that in half of patients, urticaria is diagnosed as an isolated symptom that does not develop into angioedema, but in the other half, Quincke's edema often develops very quickly.

Urticaria of allergic origin is not contagious in itself and is not transmitted by contact or airborne droplets. However, urticaria can be a symptom of an infectious, rather than allergic, disease, in which case the patient is a source of possible infection for others.

Forms

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

1. Chronic urticaria: If urticaria lasts more than six weeks, it is considered chronic.
2. Acute urticaria lasts for several hours or days. The total duration does not exceed six weeks.

Chronic urticaria in clinical practice is most often found in women, the acute form - in children and adolescents in puberty. Allergists say that the acute form of urticaria does not require serious treatment, since it goes away on its own, provided that it is clearly diagnosed. However, 10% of all allergy sufferers experience a transition from the acute form to the chronic form, when therapy can be quite long, however, after 6-8 months, a 100% complete recovery occurs.

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

• A domestic cause of a mechanical nature is compression and friction from uncomfortable clothing or an object (pressure urticaria, dermographic urticaria);
• Exposure to solar radiation - solar urticaria;
• Water exposure - aquagenic urticaria;
• Psycho-emotional impact, stress, aggravated by stuffiness; dry air in the room – cholinergic urticaria;
• Heat exposure - heat urticaria;
• Exposure to cold - cold urticaria.
• Insect bites, skin contact with external medications – papular or contact urticaria.

The rarest subtypes are vibrational (due to exposure to constant vibration, for example, from an industrial device).

Description of types of urticaria

1. Dermographic subtype of urticaria, which is called urticarial dermographism. Such urticaria is one of the forms of mechanical rash and is provoked by friction or irritation of the skin. The cause may be uncomfortable clothing, an item that a person is forced to use constantly due to his profession.
2. Solar urticaria, which appears as a reaction to excessive sunbathing or simply due to intolerance to ultraviolet radiation.
3. A very rare type of urticaria is aquagenic, which is provoked by contact with any water and is characterized by severe itching and erythematous rashes. 4.
4. Cholinergic type, which is a consequence of excessive sweating. Activation of sweat secretion is in turn provoked by a psychoemotional factor, which causes a typical vegetative reaction. A person's body temperature can increase by several degrees without any visible inflammatory causes. Less often, cholinergic urticaria appears after being in a very stuffy, hot room or due to physical overexertion. This type of urticaria manifests itself as diffuse multiple rashes all over the body and quite often ends with Quincke's edema.
5. Cold urticaria, which was also considered a rare allergic type until recently. Today, every tenth allergy sufferer suffers from cold urticaria, apparently due to the general allergy orientation of the body. A cold reaction can be provoked not only by external exposure to cold air, but also by drinking cold drinks, eating cold foods, and even touching a cold object.
6. Heat urticaria is similar to cold urticaria, but is triggered by contact with warm air or consumption of hot foods and drinks. This type of rash is extremely rare.
7. Mastocytosis or urticaria pigmentosa is an autoimmune disease in which an excessive number of mast cells (mastocytes) accumulate in tissues.
8. Papular urticaria is a contact form, provoked by small insects that bite human skin. The rash is very characteristic and appears as tiny nodules - papules.

Urticaria also has unclear, poorly studied types, which include neuropsychic, more similar to the cholinergic type, there is recurrent urticaria, idiopathic urticaria - these are types of disease with an unclear etiology.

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Complications and consequences

The most dangerous consequence of urticaria is angioedema, that is, Quincke's edema, which can develop in the acute form of the allergic disease. However, in allergological practice, such cases are very rare. All other types of urticaria are completely harmless and do not pose a threat to the patient's life. The only unpleasant symptom is severe, incessant itching. Most often, urticaria occurs in an acute form and goes away within a day, a week at most. Rarely, acute urticaria lasts more than a month, this happens when the rash is provoked by an infectious disease. As soon as the underlying cause is eliminated, both the itching and blisters go away. The chronic form of urticaria is more uncomfortable, but also does not threaten serious complications.

Diagnostics urticaria

Diagnosis of urticaria usually involves an assessment of clinical symptoms, medical history, and, if necessary, additional laboratory tests. Here are the main diagnostic steps:

Evaluation of clinical symptoms

1. Physical examination: The doctor evaluates the characteristic skin rash, which may be red, itchy, and swollen (hives).
2. Assessing the duration and frequency of symptoms: It is important to determine whether the urticaria is acute (less than 6 weeks) or chronic (more than 6 weeks).

Medical history

1. Allergic reactions and allergens: collecting information about possible allergens that could cause a reaction.
2. Medications and foods: Determine if any medications or foods have been taken that may be associated with hives.
3. Family and personal history: clarification of the presence of allergies or autoimmune diseases in the patient or his close relatives.

Laboratory and other studies

1. Complete blood count: May reveal signs of an allergic reaction or inflammation.
2. Allergy testing: Skin tests or blood tests for specific iGE antibodies can help identify specific allergens.
3. Autoimmune tests: If autoimmune urticaria is suspected, appropriate tests may be performed.
4. Physical tests: If physical urticaria is suspected, physical stimulus tests (eg, cold urticaria test) may be performed.

Differential diagnosis

It should be noted that urticaria can be similar in symptoms to other diseases. The most common of these are:

1. Systemic or cutaneous mastocytosis (urticaria pigmentosa) is a diffuse infiltration of the skin that begins with the appearance of small blisters.
2. Urticarial vasculitis, which, unlike classic urticaria, lasts from 3 to 7 days.
3. Drug rash is an allergy to contact with external medications.
4. Atopic dermatitis (allergic dermatitis).
5. Scabies is a carodermatitis caused by a mite.
6. Anaphylactoid purpura is a capillary toxicosis, a hemorrhagic disease.
7. Contact dermatitis is a delayed-type allergic skin reaction.
8. Erythema multiforme is an exudative rash.

Treatment urticaria

Therapeutic measures that help to stop urticaria are aimed primarily at neutralizing the cause of the disease. This is why differential diagnostics of urticaria as a symptom is so important. If the main allergen is identified, the first stage of therapy is the elimination (limitation of contact, exclusion from the diet) of the provoking trigger. If urticaria is caused by an infection, antibacterial therapy is carried out. Further treatment of urticaria, as a rule, differs little from the standard treatment regimen for allergies and consists of prescribing the following drugs:

1. Antihistamines that act on histamine receptors (H1 receptors or H2 receptors). These drugs effectively relieve itching and other uncomfortable symptoms of urticaria.
2. Immunomodulatory drugs are most often indicated for chronic urticaria.
3. If urticaria is accompanied by bronchospasm, antileukotriene drugs may be prescribed to relieve asthma attacks.

Quincke's edema requires immediate medical attention. It is usually treated with immediate administration of epinephrine (adrenaline).

Urticaria in any form and any kind requires adherence to a hypoallergenic diet, even if it is not caused by a food trigger. All products containing tyramine are excluded from the diet - hard cheeses, red wine, liver, dry sausage, legumes, beer. It is also necessary to refuse all types of citrus fruits, cocoa, chocolate, nuts and honey, limit the consumption of chicken eggs. The diet should be followed for at least three weeks, the further menu depends on the dynamics of the disease and the improvement of the condition.

Prevention

Prevention of urticaria involves a number of measures aimed at minimizing exposure to known triggers and reducing the risk of developing or worsening symptoms. Key prevention recommendations include:

Avoiding known triggers

1. Allergens: Avoid foods, insects, animals, or other allergens that may have triggered hives in the past.
2. Medications: Avoid medications (such as certain antibiotics or NSAIDs) if they have previously triggered urticaria.
3. Physical factors: If hives are associated with physical factors such as pressure, cold or heat, avoid those conditions.

Healthy lifestyle

1. Nutrition: A balanced diet with adequate vitamins and minerals can strengthen the immune system.
2. Regular exercise: Physical activity improves overall health and can help manage stress.
3. Get enough sleep: Quality sleep is important for supporting your immune system and reducing stress.

Stress management

1. Relaxation techniques: Yoga, meditation, and breathing exercises can help reduce stress, which can contribute to hives flare-ups.
2. Psychological support: Consulting with a therapist or participating in support groups can be helpful.

Skin care

1. Avoid irritants: Use gentle, fragrance-free skin care products and avoid products that irritate or dry out your skin.
2. Protection from cold and sun: Wear protective clothing in cold weather and use sunscreen.

Regular monitoring

1. Keep a journal: Record foods, medications, skin care products, and other factors to identify possible triggers.
2. Regular medical check-ups: Regular visits to your doctor will help monitor your condition and adjust your treatment if necessary.

Preventing hives requires an individualized approach that takes into account personal triggers, lifestyle, and overall health. It is important to remember that in some cases, it may not be possible to completely avoid hives, but taking preventive measures can significantly reduce the frequency and severity of episodes.

Forecast

The prognosis for urticaria depends largely on the type, cause, and response to treatment. Here is a general overview of the prognosis for different forms of urticaria:

Acute urticaria

• General prognosis: Acute urticaria usually has a good prognosis. In most cases, it disappears within a few days or weeks.
• Treatment: Often successfully controlled with antihistamines and avoidance of known triggers.

Chronic urticaria

• General prognosis: Chronic urticaria can be more persistent and difficult to treat. It can last for months or even years, but most cases improve over time.
• Treatment: May require a more comprehensive approach, including long-term use of antihistamines and, in some cases, immunosuppressive therapy.

Autoimmune urticaria

• Prognosis: May be more difficult to treat, but modern treatments usually control symptoms.

Physical urticaria

• Prognosis: Varies depending on the type and severity of triggers. Some patients may improve over time.

Factors Affecting Prognosis

• Identifying and avoiding triggers: Successfully identifying and avoiding triggers can significantly improve prognosis.
• Comorbidities: Having coexisting allergic or autoimmune diseases can complicate the treatment and management of urticaria.

Psychological aspects

• Impact on quality of life: Chronic urticaria can negatively impact quality of life, causing stress and anxiety. Psychological support may be necessary.

In general, urticaria usually has a favorable prognosis, especially in the acute form. Chronic urticaria may require longer and more intensive treatment, but modern methods usually allow good control of symptoms. Close cooperation with the doctor is important to optimize treatment and management of the condition.

Famous and Influential Books on Urticaria

"Urticaria and Angioedema" - Markus Moritz, 2009.

"Clinical Handbook of Urticaria" - Allen Kaplan and Malcolm Grech, 2014.

"Urticaria: Fundamentals and Clinical Practice" - Clive Grattan and Malcolm Grech, 2004.

"Urticaria: From Science to Practice" - Thorsten Zuberbier and Claudio Gelotti, 2010.