Medically reviewed by Katlein Franca, MD Doctors use a process of elimination to diagnose chronic hives, rather than a single test.The diagnostic process involves determining how long the hives have ...

In a healthy body, mast cells (the “lookout” cells of the immune system) only release histamine when they detect a foreign invader, like pollen or venom. In CSU, these cells dump histamine into the ...

Hives, or urticaria, can occur for many reasons, such as exposure to an allergen or a physical trigger, like pressure from tight clothing. It may also indicate an infection or another underlying ...

Hives (urticaria) are a common skin reaction that causes bumps, raised patches, or both. They are one way the body responds ...

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Both bug bites and hives can cause red, itchy bumps on your skin. While it can be difficult to tell them apart, learning key features and characteristics of each can help. Hives and bug bites are ...

Stress affects every aspect of our lives and how you cope has a big impact on your overall health, including your skin. If you have hives, stress can cause a flare-up of hives. Such "stress rash," the ...

Norovirus doesn’t usually cause a rash, though some people develop hives. A rash that accompanies stomach symptoms may suggest a different stomach virus or inflammatory bowel disease. Norovirus is a ...

This informational guide, part of PS's Condition Center, lays out the realities of this health concern: what it is, what it can look like, and strategies that medical experts say are proven to help.

Pimples or a pimple-like rash can develop on any part of the body, including on the legs and thighs. Potential causes include folliculitis, keratosis pilaris, and hives. Pimples often appear as one or ...