Hives

Also called urticaria

Hives are welts on the skin that often itch. These welts can appear on any part of the skin. Hives vary in size from as small as a pen tip to as large as a dinner plate. They may connect to form even larger welts.

A hive often goes away in 24 hours or less. New hives may appear as old ones fade, so hives may last for a few days or longer. A bout of hives usually lasts less than 6 weeks. These hives are called acute hives. If hives last more than 6 weeks, they are called chronic hives.

Acute hives often result from an allergy, but they can have many other causes.

The medical term for hives is urticaria (ur-tih-CAR-ee-uh). When large welts occur deeper under the skin, the medical term is angioedema (an-gee-oh-eh-dee-ma). This can occur with hives, and often causes the eyelids and lips to swell.
In severe cases, the throat and airwaycanswell, making breathing or swallowing difficult.

If this occurs, the person needs emergency care right away.

Source: https://www.aad.org

Signs, symptoms

The most common signs (what you see) of hives are:

• Slightly raised, pink or red swellings on the skin.
• Welts that occur alone or in a group, or connect over a large area.
• Skin swelling that subsides or goes away within 24 hours at 1 spot but may appear at another spot

As for symptoms (what you feel), hives usually itch. They sometimes sting or hurt.

Some people always get hives in the same spot or spots on their body. These people often have a trigger (what causes the hives). Every time they are exposed to that trigger, they get hives.

Your dermatologist may call this type of hives fixed, which means not moving. Fixed hives may happenwhen a person takes a certainmedicine (fixed drug eruption) or gets too much sunlight (fixed solar urticaria).

Source: https://www.aad.org

Who gets, causes

Who gets hives?

Hives are common. Anyone can get them.

What causes hives?

An allergic reaction cantrigger hives. Things that commonly trigger an allergic reaction include:

• Foods: Fruits (especially citrus fruits), milk, eggs, peanuts, tree nuts, and shellfish.
• Medicines.
• Insect bites and stings.
• Animals.
• Pollen.
• Touching something to which you are allergic, such as latex.
• Allergy shots.

Other causes of hives are:

• Infections, including colds and infections caused by some bacteria or fungi.
• Some illnesses, including a type of vasculitis, lupus, and thyroid disease.
• Exposure to sun (solar urticaria), heat, cold, or water.
• Exercise.
• Stress.
• Pressure on the skin, such as from sitting too long.
• Contact with chemicals.
• Scratching the skin.

Hives can happen within minutes of exposure to the trigger. Or you can have a delayed reaction of more than two hours.

Source: https://www.aad.org