Idiopathic urticaria

Idiopathic urticaria is a condition characterized by the appearance of urticaria (or urticaria-like rash) on the skin without a clear known cause. The term idiopathic means that the cause of the condition remains unclear or unknown. Urticaria is a skin condition that is manifested by the sudden appearance of a rash that may be itchy, red and swollen. The rash usually consists of areas that resemble insect bites and can vary in size and shape. [1]

Risk factors

The causes of idiopathic urticaria remain unclear, which is why it is called "idiopathic" (that is, without a clearly known cause). However, there are several factors that may play a role in the development of this condition:

1. Allergic reactions: Some cases of idiopathic urticaria may be associated with allergic reactions to food, medications, insects, or other allergens. In such cases, it is sometimes referred to as "allergic urticaria". However, it is not always possible to determine the exact cause of the allergy.
2. Immunologic factors: Immunologic changes in the body can also contribute to the development of urticaria. For example, immune system disorders can lead to an overreaction to irritants, causing hives.
3. Stressand psychoemotional factors: Stress and psychoemotional conditions can worsen or exacerbate urticaria symptoms. Some studies have linked urticaria to stress.
4. Genetic predisposition: Hereditary factors may play a role in the development of urticaria. If family members have a history of the disease, the risk of developing urticaria may be increased.
5. Other medical conditions: Some medical conditions, such as autoimmune diseases or immune system disorders, may be associated with urticaria. [2]

Pathogenesis

The pathogenesis of idiopathic urticaria (as well as the pathogenesis of urticaria in general) remains incompletely understood, and research in this area is ongoing. However, it is believed that inflammatory mediators, particularly histamine, play a key role in the development of urticaria. [3], [4]

In general terms, the pathogenesis is as follows:

1. Mastocyte activation: M astocytes are cells that contain chemicals, including histamine. When exposed to various stimuli (possibly including allergens, stress, physical activity, and other factors), mastocytes can become activated.
2. Histamine release: Activated mastocytes release histamine, which is a potent mediator of inflammation. Histamine causes vasodilation, increased capillary permeability and inflammation in the skin.
3. Skin reaction: Exposure to histamine causes a skin reaction characterized by rash, itching, redness and swelling. These symptoms characterize urticaria.

Symptoms of the idiopathic urticaria

Idiopathic urticaria is characterized by sudden and unpredictable rash attacks and can present with a variety of symptoms including:

1. Rash: One of the main symptoms of idiopathic urticaria is the appearance of a rash on the skin. The rash can vary in shape and size, it is usually itchy and can be red, pink or purple.
2. Itching: Severe itching is a characteristic symptom of urticaria. The itching can be intense and cause discomfort.
3. Redness and swelling: The skin at the site of the rash may become red and swollen.
4. Displacement of the rash: A characteristic of urticaria is that it moves quickly. The rash may appear in one place and disappear, then reappear in another.
5. Atypical symptoms: Sometimes idiopathic urticaria may be accompanied by other symptoms such as headache, fever, dizziness or nausea. In rare cases, it can cause angioedema, a rapidly developing swelling of the skin, mucous membranes and subcutaneous tissues, which is a more serious condition and requires immediate medical attention.

The symptoms of idiopathic urticaria may vary depending on the individual characteristics of the patient and the severity of the condition. Periods of exacerbation may be followed by periods of remission, when symptoms disappear. [5], [6]

Forms

Idiopathic urticaria can manifest in a variety of ways, including:

1. Acute urticaria: This form is characterized by the sudden onset of a rash and symptoms that may bother the patient greatly, but usually rarely last long. The rash may appear and disappear within a few hours or days.
2. Chronic urticaria: This form is characterized by longer periods of rash that may last for weeks or months. Symptoms may vary and include itching, swelling, redness of the skin, and other discomfort.
3. Angioedema: This is a form in which urticaria is accompanied by angioedema, a rapidly developing swelling of the skin, mucous membranes, and subcutaneous tissues. This type of urticaria can be more serious and may require immediate medical attention, as the swelling can affect the airways and cause gasping.
4. Other forms: In rare cases, idiopathic urticaria may present in more unusual forms or with associated symptoms such as fever, headache, or joint pain.

Complications and consequences

Idiopathic urticaria is usually a self-limiting condition and rarely leads to serious complications. However, some of the complications may include:

1. Angioedema: This is a serious complication in which swelling of the skin, mucous membranes and subcutaneous tissues occurs, which can lead to breathing difficulties and can be life-threatening. Patients with angioedema require immediate medical attention.
2. Decreased quality of life: Idiopathic urticaria, especially its chronic form, can significantly reduce the quality of life of patients due to unpleasant symptoms such as itching, swelling and skin pain.
3. Psychological problems: Constant rashes and discomfort can cause stress and anxiety in patients, which can lead to psychological problems such as depression and social isolation.
4. Transition to the chronic form: In some patients, the acute form of idiopathic urticaria can progress to the chronic form, which can last for months or even years.
5. Medication complications: Treatment of idiopathic urticaria may require taking antihistamines and other medications that can cause side effects.

Diagnostics of the idiopathic urticaria

Diagnosis of idiopathic urticaria is usually based on characteristic symptoms and clinical examination of the patient. The physician takes a history, talks to the patient about symptoms and circumstances that might have caused the rash, and performs a physical examination. The following diagnostic techniques may be necessary to rule out other possible causes of the rash or allergic reactions that may mimic urticaria:

1. Clinical examination: The doctor evaluates the external signs of the rash, including its shape, size, color, and location. He or she also looks for other symptoms such as itching, swelling, and pain in the skin.
2. Allergytests: If an allergic reaction is suspected as the cause of the rash, your doctor may recommend allergy tests to determine the allergens causing the reaction.
3. Blood tests: Blood tests may be done to assess the level of inflammation or the presence of other possible medical conditions.
4. Foodsand diet: Sometimes the rash may be food-related. The doctor may recommend that the patient keep a food diary and eliminate certain foods to determine if certain foods are causing the rash.
5. Exclusion of infectious causes: In some cases, hives may be associated with infectious diseases. The doctor may suggest ruling out such infections through laboratory tests.
6. Additional tests: In some cases, additional tests, such as a skin biopsy, may be needed to rule out other possible diagnoses.

Differential diagnosis

The differential diagnosis of idiopathic urticaria involves ruling out other possible causes of the rash and allergic reactions. Below are some of the conditions and diseases that can mimic the symptoms of urticaria and should be ruled out at diagnosis:

1. Allergic reaction: Various allergens such as food, medications, insects, and pets can cause an allergic rash that can mimic the symptoms of hives.
2. Contact dermatitis: This skin condition is caused by contact with irritating substances such as chemicals, plants or metals. Contact dermatitis can cause skin rashes and itching.
3. Infectious diseases: Some infections, including viruses, bacteria, and fungi, can cause skin rashes and itching. For example, chickenpox, rubella, or fungal infections.
4. Autoimmune diseases: Some autoimmune diseases, such as lupus erythematosus or dermatomyositis, can manifest with skin rashes and skin inflammation.
5. Physical factors: Reactions to physical factors such as cold, heat, physical stress, or pressure on the skin can cause urticaria (a type of hives).
6. Systemic diseases: Some systemic diseases, such as systemic lupus erythematosus or sarcoidosis, may present with skin symptoms.

For differential diagnosis and to establish the correct diagnosis, the doctor may perform a detailed clinical examination, as well as use laboratory tests, allergy tests and other diagnostic methods.

Treatment of the idiopathic urticaria

Treatment for idiopathic urticaria is aimed at relieving symptoms, reducing itching, and preventing recurrences. Your doctor may recommend the following treatments:

1. Antihistamines: This is the main treatment for hives. Antihistamines, available with or without a prescription, help reduce itching and swelling of the skin. Your doctor may prescribe one of the following categories of antihistamines:

The first generation of antihistamines:

• Diphenhydramine (Benadryl): This is one of the best-known first-generation antihistamines. It can cause drowsiness and impair concentration, so it is often not recommended for use before driving or performing tasks that require alertness.
• Hydroxyzine (Atarax, Vistaril): This medication can also cause drowsiness and is often used to relieve anxiety and restlessness.

Second generation antihistamines:

• Cetirizine (Zyrtec): Cetirizine usually does not cause drowsiness and has a long-lasting effect, allowing it to be taken once a day.
• Loratadine (Claritin): Loratadine is also well tolerated and does not usually cause drowsiness.
• Fexofenadine (Allegra): This drug usually does not cause drowsiness and has a long-lasting effect.

2. Corticosteroid medications: If symptoms are severe or there is no response to antihistamines, your doctor may prescribe corticosteroid ointments or creams to reduce inflammation and itching of the skin. [7]

Corticosteroid ointments and creams are available by prescription only in most countries. The following are some examples of corticosteroid ointments and creams that can be used to treat idiopathic urticaria, but the exact drug choice and dosage should be determined by your doctor depending on the severity of symptoms and the area of skin affected:

• Hydrocortisone ointments: For example, hydrocortisone ointment 1%. It is applied in a thin layer to the affected skin area 1-2 times a day.
• Mometasone (Elocon): This is a stronger corticosteroid. It is applied in a thin layer to the affected area once a day.
• Fluticasone (Cutivate): Apply a thin layer to the affected area once a day.
• Triamcinolone (Kenalog): This is a corticosteroid medication, sometimes available in ointment form. The dosage and frequency of use are determined by your doctor.
• Desonate: Apply a thin layer to the affected area 2 times a day.

Here are some key points on the use of corticosteroid ointments or creams:

• Consultation with a doctor: Before you start using corticosteroid medications, it is important to consult a doctor or dermatologist. Your doctor will determine the appropriate medication, dosage, and duration of treatment depending on the severity of your symptoms.
• Skin application: The ointment or cream should be applied to clean and dry skin in the area of the rash. Patients are advised to avoid rubbing or chafing the skin.
• Avoid face and supraorbital areas: Corticosteroids are generally not recommended for use on the face or supraorbital areas, as these skin areas are more sensitive to side effects.
• Follow the dosageand recommendations: It is important to follow your doctor's instructions regarding the dosage and duration of treatment. Do not stop using the drug early or exceed the recommended dose.
• Monitoring side effects: During treatment, monitor your skin condition and report any unpleasant symptoms or side effects to your doctor.
• Gradual dose reduction: Once improvement in symptoms is achieved, your doctor may gradually reduce the dose of a corticosteroid medication to avoid a relapse or reduce the risk of side effects.

It is important to follow your doctor's instructions regarding the choice of a particular medication and its dosage. Corticosteroid ointments and creams should be applied lightly and evenly to the skin, avoiding rubbing or chafing.

3. Epinephrine (adrenaline): In cases of angioedema or anaphylactic reaction, which may be a complication of idiopathic urticaria, epinephrine may need to be administered under the supervision of medical personnel.
4. Avoidance of provoking factors: Patients may be advised to avoid known provoking factors such as certain foods, medications, or physical exposures.
5. Stress management: Emotional stress can exacerbate urticaria symptoms. Patients are advised to learn to manage stress through relaxation and other techniques.
6. Treatment for chronic: If hives have become chronic (lasting more than 6 weeks), your doctor may consider additional treatments, such as courses of corticosteroids or immunomodulators.

Prevention

Idiopathic urticaria is usually an allergic condition, and predicting its exact causes can be difficult. However, there are some general guidelines and preventive measures that can help reduce the risk of symptoms:

1. Avoid known allergens: If you have knownallergies to certain foods, medications or substances, avoid eating or coming into contact with them.
2. Manage stress: Stress can contribute to worsening allergic reactions. Try relaxation techniques such as yoga, meditation or deep breathing to reduce stress.
3. Follow a healthy lifestyle: Eating a healthy diet, exercising regularly and getting enough sleep can strengthen your immune system and help reduce the risk of allergic reactions.
4. Avoid heavy physical activity in cold temperatures: Freezing (hives caused by cold) can be prevented by wearing warm clothing in cold weather and avoiding prolonged exposure to the cold.
5. Take antihistamines as prescribed by your doctor: If you already have a diagnosis of idiopathic urticaria, your doctor may prescribe antihistamines to treat and prevent exacerbations.
6. Keep track of medications: If you are allergic to certain medications, make sure your doctor and pharmacist know about it to avoid prescribing or dispensing allergy medications.
7. Consult an allergist or immunologist: If you have frequent or severe cases of idiopathic urticaria, see an allergist or immunologist for a more detailed analysis and management of your condition.

Forecast

The prognosis of idiopathic urticaria (urticaria of unknown nature) can vary from person to person. In most patients with idiopathic urticaria, symptoms may be mild and may change over time. In some cases, the urticaria may resolve on its own or become less severe over time, while in others it may remain for many years.

It is important to note that idiopathic urticaria is often characterized by relapses, that is, repeated episodes of rash and itching. The severity and duration of symptoms may vary from case to case. Management of idiopathic urticaria usually involves treatment with antihistamines, which help to alleviate symptoms and prevent exacerbations.

The prognosis may also depend on how well the patient responds to treatment and how long the periods of exacerbation are. Some patients require more intensive and prolonged treatment, while others can easily control symptoms with antihistamines.

It is important to follow your doctor's recommendations, take the medication according to the prescribed dosage, and communicate regularly with your doctor about your skin condition and the effectiveness of treatment. If you experience new or worsening symptoms, be sure to seek medical attention.

Literature used

Khaitov, R. M. Allergology and immunology : national guide / Edited by R. M. Khaitov, N. I. Ilyina. - Moscow : GEOTAR-Media, 2009.