What is the most common cause of urticaria?

The most common cause of urticaria, also known as hives, is the activation of IgE and mast cells. In this process, specific allergens, which could be food, medications, insect stings, or environmental factors, lead to the cross-linking of IgE antibodies bound to mast cells. This results in the release of histamine and other mediators, causing the characteristic wheals, redness, and itching associated with urticaria.

When mast cells degranulate, they release histamine, which increases vascular permeability, leading to fluid leakage from the blood vessels into the surrounding tissues, causing the swelling and redness. This immediate hypersensitivity reaction typically manifests within minutes after exposure to an allergen, highlighting IgE's central role in the pathogenesis of urticaria.

While autoimmune mechanisms and drug hypersensitivity reactions can also cause urticaria, they are not the most common causes. Autoimmune urticaria can occur when the immune system mistakenly targets the body’s own tissues, but this is less prevalent compared to allergic responses involving IgE. Drug hypersensitivity can also lead to urticaria, especially with certain medications, but it is also not as frequent as the IgE-mast cell activation route. Therefore, the role