Urticaria, also known as hives, is a skin rash that presents as itchy red bumps or lumps called weals. The welts that come with hives are caused by the release of immune system chemicals, such as histamine, into the bloodstream. Hives can be acute or chronic, spontaneous or inducible. Acute urticaria refers to hives that don’t last very long (less than six weeks), while chronic urticaria refers to hives that happen at least twice a week for more than six weeks. The main symptom of hives is a rash that can be raised, very itchy, and can range in size from a few millimeters to the size of a dinner plate. Hives can be caused by a variety of factors, including:

• Allergens: such as food, medication, insect bites or stings, pollen, dust mites, or latex.
• Physical triggers: such as exposure to heat, cold, pressure, or sunlight.
• Emotional stress.
• Medical conditions: such as thyroid disease, infection, allergy, or cancer.

Treatment for hives may include antihistamines or steroids. If you experience hives that dont improve after two days, are severe, or are accompanied by other symptoms such as swelling under the skin, you should speak to a doctor.