There are many causes of hives including foods, drugs, infections, and diseases. Oddly enough, even though there are many potential causes, in the majority of cases of hives, the cause is unknown. Hives causes can be broken down into 3 broad groups:
- Idiopathic: This means we don't know the cause; it just happens.
- Immunological: Some hives are caused by changes in the immune system. A typical scenario would be coming in contact with something that causes cells in the immune system to trigger the release of histamine from certain white blood cells called mast cells.
- Nonimmunological: Exposure to certain substances can cause the direct release of histamine from mast cells without the involvement of other parts of the immune system.
If you have hives, you want to know what causes them so you can eliminate that trigger and free yourself from the itching. The following lists are not exhaustive, but do give the main known hives causes. While most cases of hives are idiopathic, see if you can eliminate any obvious causes of your hives. Just remember that it's best to talk to your healthcare provide before eliminating all possible hive triggers. If you suspect medication is causing your hives, contact your healthcare provider immediately.