Allergy & Asthma Care Information - hives / swelling information


At some time in their lives approximately 20% of people in the U.S. will develop hives (“urticaria”) and/or swelling (“angioedema”) involving various parts of their body. Hives and swelling are related problems and the approach to both of these problems is the same. Both are caused by excess histamine release from skin white blood cells (MAST cells) generally due to a temporary state of fragile MAST (histamine releasing) cells. Histamine causes marked itching as well as fluid swelling in skin.

Hives form because something (usually the spontaneous release of histamine) causes the blood vessels in an area of skin to expand (causing local redness) and become leaky, so fluid escapes into the surrounding skin leading to swelling and hives.

Doctors call hives of unknown cause “idiopathic urticaria.” In Greek idiopathic means “unknown cause” and urticaria means “hives” (i.e., idiopathic urticaria=hives of unknown cause). The medical term for swelling is angioedema, “also taken from the Greek “angio” meaning blood vessel and “edemos” meaning swelling. This name is derived from the way hives form as described in the previous note.

If you would like additional detailed information on hives and swelling, contact us and make an appointment at our clinic.

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Located in Medford, Oregon with satellite offices in Grants Pass, Ashland, and Klamath Falls, the Allergy and Asthma Center of Southern Oregon, PC offers exceptional care for patients with allergies and asthma.

Allergy & Asthma Information

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