Allergic Urticaria
Disease Details
Family Health Simplified
- Description
- Allergic urticaria, commonly known as hives, is a skin reaction characterized by red, itchy welts that result from an allergic response.
- Type
- Allergic urticaria is considered a Type I hypersensitivity reaction. It does not follow a specific pattern of genetic transmission because it is primarily caused by an inappropriate immune response to allergens rather than a hereditary condition. However, a familial predisposition to allergies, including allergic urticaria, can increase the likelihood of developing the condition.
- Signs And Symptoms
- Hives, or urticaria, is a form of skin rash with red, raised, itchy bumps. They may also burn or sting. Hives can appear anywhere on the surface of the skin. Whether the trigger is allergic or not, a complex release of inflammatory mediators, including histamine from cutaneous mast cells, results in fluid leakage from superficial blood vessels. Hives may be pinpoint in size or several inches in diameter, they can be individual or confluent, coalescing into larger forms.About 20% of people are affected. Cases of short duration occur equally in males and females, lasting a few days and without leaving any long-lasting skin changes. Cases of long duration are more common in females. Cases of short duration are more common among children while cases of long duration are more common among those who are middle aged. Fewer than 5% of cases last for more than six weeks. The condition frequently recurs. In half of cases of hives, the cause remains unknown.Angioedema is a related condition (also from allergic and nonallergic causes), though fluid leakage is from much deeper blood vessels in the subcutaneous or submucosal layers. Individual hives that are painful, last more than 24 hours, or leave a bruise as they heal are more likely to be a more serious condition called urticarial vasculitis. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermatographic urticaria.
- Prognosis
- In those with chronic urticaria, defined as either continuous or intermittent symptoms lasting longer than 6 weeks, 35% of people are symptom free 1 year after treatment, while 29% have a reduction in their symptoms. Those with a longer disease duration typically have a worse prognosis, with greater symptom severity. Chronic urticaria is often accompanied by an intense pruritus, and other symptoms associated with a reduced quality of life and a high burden of co-morbid psychiatric conditions such as anxiety and depression.
- Onset
- Onset of allergic urticaria typically occurs within minutes to a few hours after exposure to an allergen.
- Prevalence
- The prevalence of allergic urticaria, commonly known as hives caused by allergic reactions, varies widely but is estimated to affect around 15-20% of people at some point in their lives.
- Epidemiology
- Chronic urticaria is usually seen in those older than 40 years, it is more common in women. The prevalence of chronic urticaria is 0.23% in the United States.
- Intractability
- Allergic urticaria, commonly known as hives, is generally not considered intractable. Most cases can be effectively managed with antihistamines or other medications. However, some individuals may experience chronic or recurrent symptoms, which can be more challenging to treat but are typically manageable with specialized care and lifestyle adjustments.
- Disease Severity
- Allergic urticaria, commonly known as hives, can vary in severity. It ranges from mild, presenting as small, localized welts, to severe, with extensive swelling and larger welts. Severe cases may require medical attention, especially if accompanied by symptoms of anaphylaxis, such as difficulty breathing or swelling of the tongue or throat.
- Healthcare Professionals
- Disease Ontology ID - DOID:10612
- Pathophysiology
- The skin lesions of urticarial disease are caused by an inflammatory reaction in the skin, causing leakage of capillaries in the dermis, and resulting in an edema which persists until the interstitial fluid is absorbed into the surrounding cells.Hives are caused by the release of histamine and other mediators of inflammation (cytokines) from cells in the skin. This process can be the result of an allergic or nonallergic reaction, differing in the eliciting mechanism of histamine release.
- Carrier Status
- Allergic urticaria, commonly known as hives, is not a genetic condition, so there is no carrier status associated with it. It occurs due to an allergic reaction to various triggers, such as foods, medications, or other allergens.
- Mechanism
-
Allergic urticaria, commonly known as hives, is primarily an immunological reaction involving the release of histamine and other inflammatory mediators from mast cells and basophils. The mechanism can be divided into several key steps:
1. **Mechanism**:
- **Allergen Exposure**: The body is exposed to an allergen, which can be a substance like certain foods, medications, insect stings, or environmental factors.
- **IgE Sensitization**: In susceptible individuals, the immune system mistakenly identifies the allergen as harmful and produces Immunoglobulin E (IgE) antibodies specific to that allergen.
- **Mast Cell and Basophil Activation**: Upon re-exposure to the same allergen, the allergen cross-links with the IgE antibodies bound to the surface of mast cells and basophils.
- **Histamine Release**: This cross-linking triggers these cells to release histamine and other pro-inflammatory molecules.
2. **Molecular Mechanisms**:
- **Histamine**: When released from mast cells, histamine binds to H1 receptors on endothelial cells, leading to increased vascular permeability and causing fluid to leak into tissues, which manifests as the localized swelling and redness characteristic of hives.
- **Cytokines and Chemokines**: In addition to histamine, other cytokines such as TNF-α and IL-4 are released, which further contribute to the inflammatory response.
- **Leukotrienes and Prostaglandins**: These lipid mediators are released and amplify the inflammatory response by increasing vascular permeability and attracting additional immune cells to the site.
- **Signal Transduction**: The binding of allergens to IgE leads to the activation of intracellular signaling pathways involving kinases such as Lyn and Syk, and downstream transcription factors like NF-κB, which regulate the production of inflammatory mediators.
These molecular events collectively result in the clinical presentation of urticaria, characterized by transient, itchy, red, or skin-colored welts on the surface of the skin. - Treatment
-
The treatment for allergic urticaria typically involves:
1. **Antihistamines**: These are the first line of treatment and help to reduce itching and swelling.
2. **Avoiding Triggers**: Identifying and avoiding specific allergens that trigger reactions.
3. **Corticosteroids**: For severe cases, oral or topical corticosteroids can be prescribed.
4. **Epinephrine**: In cases of anaphylaxis, an epinephrine injection is necessary.
5. **Cool Compresses**: Applying cool compresses to affected areas to reduce discomfort.
6. **Immunotherapy**: For chronic cases, allergen-specific immunotherapy may be considered.
Consulting with a healthcare provider is important for a tailored treatment plan. - Compassionate Use Treatment
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Compassionate use treatment and off-label or experimental treatments for allergic urticaria may be considered in cases where standard therapies are ineffective. Here are some examples:
1. **Omalizumab (Xolair)**: Originally approved for asthma, it has shown effectiveness in treating chronic spontaneous urticaria that is unresponsive to antihistamines, making it an off-label option for allergic urticaria.
2. **Cyclosporine**: An immunosuppressant used off-label for severe chronic urticaria, particularly when it does not respond to antihistamines or corticosteroids.
3. **Biologic Agents**: Emerging biologic agents like dupilumab, primarily used for atopic dermatitis, are being studied for their effectiveness in treating difficult cases of allergic urticaria.
4. **Methotrexate**: An immunosuppressant that can be employed off-label in severe cases not responsive to conventional treatments.
5. **Plasmapheresis**: An experimental procedure that involves filtering the blood to remove antibodies, considered for severe urticaria linked to autoimmune conditions.
These treatments should be considered with caution and under the supervision of a healthcare professional experienced in managing refractory allergic urticaria. - Lifestyle Recommendations
-
Lifestyle recommendations for managing allergic urticaria (hives) include:
1. **Avoid Triggers**: Identify and avoid allergens or triggers that cause your urticaria. Common triggers include certain foods, medications, insect stings, and environmental factors like pollen or pet dander.
2. **Wear Loose Clothing**: Choose loose-fitting clothes made of soft fabrics like cotton to minimize skin irritation.
3. **Use Gentle Skincare Products**: Opt for mild, fragrance-free soaps and moisturizers to reduce the risk of skin irritation.
4. **Manage Stress**: Stress can exacerbate hives, so incorporate stress-reducing activities into your routine, such as yoga, meditation, or exercise.
5. **Stay Cool**: Heat can worsen urticaria symptoms, so keep cool by staying in air-conditioned environments and avoiding hot showers.
6. **Maintain Hydration**: Drink plenty of water to keep your skin hydrated and help your body flush out allergens.
7. **Dietary Adjustments**: If certain foods trigger your hives, attempt an elimination diet to identify and avoid these foods. Consult a dietitian if necessary.
8. **Regular Medical Check-ups**: Follow up with your healthcare provider regularly to manage your condition and update your treatment plan as needed. - Medication
- Drugs that have caused allergic reactions evidenced as hives include codeine, sulphate of morphia, dextroamphetamine, aspirin, ibuprofen, penicillin, clotrimazole, trichazole, sulfonamides, anticonvulsants, cefaclor, piracetam, vaccines, and antidiabetic drugs. The antidiabetic sulphonylurea glimepiride, in particular, has been documented to induce allergic reactions manifesting as hives.
- Repurposable Drugs
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Repurposable drugs for allergic urticaria, also known as hives, could include:
1. **Antihistamines**: Commonly used to reduce symptoms by blocking histamine receptors. Examples include cetirizine, loratadine, and diphenhydramine.
2. **Corticosteroids**: Typically prescribed when antihistamines are not sufficient, to reduce inflammation and immune response. Examples include prednisone.
3. **Leukotriene Receptor Antagonists**: Sometimes used as an adjunct treatment for cases not fully controlled by antihistamines. An example is montelukast.
4. **Immunosuppressants**: In severe or chronic cases, drugs such as cyclosporine may be considered.
Please consult a healthcare provider for appropriate diagnosis and treatment. - Metabolites
- For allergic urticaria, specific metabolites are not typically the central focus of diagnosis or treatment. Allergic urticaria, also known as hives, primarily involves the release of histamine and other inflammatory mediators from mast cells, leading to the characteristic skin reactions. Management often includes antihistamines and avoiding known triggers. Nanotechnology has yet to play a significant role in the standard treatment of allergic urticaria.
- Nutraceuticals
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Nutraceuticals may offer supplementary benefits for managing allergic urticaria. Some commonly discussed options include:
1. **Quercetin**: A natural flavonoid with antihistamine and anti-inflammatory properties.
2. **Probiotics**: May help in modulating the immune response and improving gut health.
3. **Omega-3 fatty acids**: Known for their anti-inflammatory effects.
4. **Vitamin D**: Can improve immune function and potentially reduce the severity of allergic responses.
Always consult with a healthcare provider before starting any nutraceuticals, as they can interact with other medications and conditions. - Peptides
- Allergic urticaria, also known as hives, is a sudden outbreak of swollen, pale red bumps or plaques on the skin that appear as a result of allergic reactions. Peptides are short chains of amino acids that can play a role in the immune response and inflammation associated with allergic urticaria. Research is ongoing into the potential therapeutic uses of peptides in treating allergic conditions, but they are not yet a standard treatment for urticaria. The abbreviation "nan" does not seem to directly relate to allergic urticaria in a clinical or biochemical context.