Causes of hives
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Common Causes of Hives (Urticaria): Allergic Reactions and Triggers
Hives, also known as urticaria, are often caused by allergic reactions. These reactions can be triggered by foods, medications, insect stings, or other allergens. The skin develops raised, red, and itchy welts that can vary in size and location. Sometimes, hives can be part of a more serious allergic reaction that includes symptoms like swelling, trouble breathing, or dizziness, which requires immediate medical attention Surekha2021Miri2019.
Acute vs. Chronic Hives: Duration and Underlying Factors
Acute urticaria is common, especially in children, and usually has an identifiable cause such as an infection, food, or medication. Chronic urticaria, defined as hives lasting more than six weeks, is less common and often does not have a clear cause. In many cases, chronic hives are considered idiopathic, meaning no specific trigger is found even after thorough evaluation. Routine allergy testing is not usually helpful for chronic hives, as it rarely identifies a cause and can lead to unnecessary dietary or lifestyle changes .
Autoimmune Causes of Chronic Hives
A significant proportion of chronic spontaneous urticaria (CSU) cases are believed to have an autoimmune basis. In these cases, the immune system mistakenly targets the body’s own cells, leading to the activation of mast cells and basophils, which release chemicals that cause hives. Both IgG and IgE autoantibodies may be involved, and the autoimmune process can target a variety of antigens, not just those on mast cells and basophils .
Gut Microbiome and Hives: The Gut-Skin Axis
Emerging research suggests that the gut microbiome may play a role in the development of chronic hives. People with chronic urticaria often have an imbalance in their gut bacteria, with lower levels of beneficial bacteria and higher levels of certain other types. This imbalance may increase gut permeability and inflammation, which can contribute to skin conditions like hives .
Infections and Parasitic Causes of Hives
Infections, including viral and parasitic infections, can sometimes cause hives. In children, chronic hives are rarely due to parasitic infections in developed countries, but this may become more relevant with increased global travel and immigration. Acute hives can also be triggered by common viral infections Poowuttikul2021Biswas2023.
Conclusion
Hives are most commonly caused by allergic reactions, but chronic cases often have no identifiable trigger and may be linked to autoimmune processes or imbalances in the gut microbiome. Infections, including rare parasitic causes, can also play a role, especially in certain populations. Understanding the underlying cause is important for effective management, but in many cases, especially chronic hives, the exact cause remains unknown Surekha2021Bracken2019Poowuttikul2021+3 MORE.
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