Urticaria (Hives) – Causes, Symptoms, Diagnosis, And Treatment
What is urticaria?
Urticaria, also called hives, is the sudden appearance of raised, itchy, red bumps (welts) on the surface of the skin. This condition is caused by an allergic reaction to food, medicine, or other substances. They can also appear without cause. These itchy bumps can appear on any part of the body and can be in different sizes and shapes. Urticaria is a common reaction. It is not contagious.
What causes urticaria?
Urticaria is most commonly caused by an allergic reaction to an allergic substance. Your immune system releases histamine into the bloodstream to fight the allergen. This causes itching, swelling, and other symptoms. People with other allergies, such as hay fever, often get urticaria.
The following substances can trigger urticaria:
- Animal dander (particularly cats)
- Insect Bites
- Shellfish, fish, nuts, eggs, milk, and other foods
Urticaria may also be triggered by:
- Emotional stress
- Extreme cold or sun exposure
- Excessive perspiration
- Illness, including lupus, other autoimmune diseases, and leukemia
- Infections such as mononucleosis
- Exposure to water
What are the symptoms of urticaria?
Symptoms of urticaria may include any of the following:
- Swelling of the surface of the skin into red or skin-colored welts with clearly defined edges.
- Welts may get bigger, spread, and join together to form larger areas of flat, raised skin.
- Welts often change shape, disappear, and reappear within minutes or hours. It is unusual for a welt to last more than 48 hours.
- Dermatographism is a type of urticaria. It is caused by pressure on the skin and results in immediate urticaria.
How is urticaria diagnosed?
A doctor can tell if you have urticaria by looking at your skin. If you have a history of an allergy-causing urticaria, for example, to strawberries, the diagnosis is even clearer.
Sometimes, a skin biopsy or blood tests are done to confirm that you had an allergic reaction, and to test for the substance that caused the allergic response. However, specific allergy testing is not useful in most cases of urticaria.
How is urticaria treated?
Generally, treatment is not needed if the urticaria is mild. It usually disappears on its own. The doctor may recommend the following to reduce itching and swelling:
- Do not take hot baths or showers.
- Do not wear tight-fitting clothing, which can irritate the area.
Your doctor may recommend the following antihistamines:
- Diphenhydramine (Benadryl)
- Cetirizine (Zyrtec).
- Other oral prescription medicines if the urticaria is chronic.
This feature is for informational purposes only and is not intended to substitute the expert guidance of a doctor. We advise seeing a doctor if you have any health concerns.