Urticaria is a skin reaction marked by itchy, red wheals. Individual hives typically last less than 24 hours, and new ones may appear as older ones fade. When hives last less than 6 weeks, this is known as acute urticaria. Hives lasting longer than 6 weeks are known as chronic urticaria. Urticaria can occur with or without swelling of the deeper subcutaneous tissue and mucosa such as the lips and tongue, known as angioedema. Angioedema may be life-threatening if swelling of the throat or tongue obstructs the airway.
Hives are commonly caused by allergies to foods, medicines, insect bites and stings and environmental elements such as animal fur and pollen. Other potential triggers include infection, illness, exercise, exposure to ultraviolet light, heat, cold or water, pressure and rubbing of the skin, certain chemicals and stress. Many cases of chronic urticaria may develop without an easily identifiable trigger.
A workup for urticaria may include blood testing, allergy testing, and/or skin biopsy.
Treatment for urticaria may include:
- Lifestyle and dietary modifications
- Topical prescriptions
- Oral medication
- Epinephrine injection in severe cases