Allergies can cause hives (urticaria) due to an immune system response triggered by the release of histamines and other chemicals. Hives are raised, itchy welts on the skin that can vary in size and shape and often appear as a result of an allergic reaction.
Hives
Here's how hives are triggered on the skin:
1. Allergen Exposure:
When an individual with allergies comes into contact with an allergen, such as certain foods, medications, insect stings, or environmental triggers, their immune system may recognise the substance as harmful.
2. Immune System Response:
The immune system responds to the perceived threat by releasing histamines and other chemicals. Histamines cause blood vessels to become more permeable, leading to fluid leakage into the surrounding tissues.
3. Skin Reaction:
The increased permeability of blood vessels in the skin results in the characteristic welts or hives. These raised, red or pink welts can appear suddenly and often cause intense itching.
4. Inflammatory Process:
The release of histamines and other inflammatory substances causes an inflammatory response in the skin, leading to the development of hives.
It's important to note that hives are not always directly related to allergies. Other factors, such as infections, stress, certain medications, and underlying medical conditions, can also trigger hives. When hives are caused by allergies, the condition is known as allergic urticaria.
Hives due to allergies can occur as part of a more generalised allergic reaction, which may also involve symptoms such as swelling (angioedema), difficulty breathing, and, in severe cases, anaphylaxis. Common allergens that can cause hives include certain foods (such as nuts, shellfish, and eggs), medications (such as antibiotics and non-steroidal anti-inflammatory drugs), insect stings, and latex.