What are hives?
Hives, also called urticaria, are red, itchy bumps on your skin. You can develop welts of different sizes, and your symptoms may range from mild to severe.
Although most cases of hives run their course and disappear, you can develop chronic hives. Patients with chronic hives have welts that appear daily for more than six weeks. Each welt disappears within 24 hours.
How can I recognize hives?
Hives often resemble a bug bite or a generic skin rash. However, hives also have specific characteristics that make them different from other skin problems:
- Bumps or welts appear suddenly and can disappear just as quickly
- Hives change shape, move around, disappear and reappear over short periods of time
- Red hives turn white if you press on the center of the hive
Hives can develop anywhere on your body, and they’re often associated with angioedema.
What causes hives?
Hives most often develop when you have an allergic reaction, but they also appear during some illnesses, especially if you have a fever. A few of the most common triggers include:
- Foods (peanuts, tree nuts, eggs, and shellfish)
- Medications (antibiotics and aspirin)
- Insect bites or stings
- Latex
- Pollen
- Poison oak and poison ivy
- Bacterial infections (strep throat and urinary tract infections)
- Viral infections (common cold, infectious mononucleosis)
You may also develop hives due to a physical trigger. For example, hives often appear when you scratch or rub your skin. Other physical triggers include cold, heat, pressure, sun exposure, or high body temperature.
What other allergy-related rashes might I develop?
The most common allergic skin conditions include:
Atopic dermatitis or eczema
Eczema occurs in about one in 50 adults and affects one in five infants, with about 60% of cases appearing before the age of one year. It causes red, itchy skin that may be swollen and have a bumpy rash, blisters that ooze, or dry patches of thickened skin.
Eczema may be triggered by many different allergens and irritants, from pollen and food to soap, skin care products, and cigarette smoke.
Allergic contact dermatitis
Contact dermatitis occurs when an allergen comes into contact with your skin, making it appear red, bumpy, scaly, itchy, or swollen. Common contact allergens include poison ivy and poison oak, nickel, latex, and wool.
What causes angioedema?
Angioedema refers to swelling that develops when fluid builds up in deep layers of your skin. The swelling and redness caused by angioedema appears in large, thick patches that are often warm or painful. Although angioedema often appears on your face, it may develop in your throat, hands, and feet.
The most common causes of angioedema include:
Allergies
About 90% of all cases of angioedema develop in response to an allergy. Hives and allergic angioedema typically occur together.
ACE inhibitors
Angiotensin-converting enzyme inhibitors (ACE inhibitors) are used to treat high blood pressure. They cause about 4-8% of all cases of angioedema.
How are allergic rashes, hives, and angioedema treated?
The first step is to identify the exact cause of your rash, hives, or angioedema. Dr. Ispas performs a skin prick test or a patch test to see which allergens trigger a reaction. Then she works with each patient to develop an individualized treatment plan, based on the cause and severity of your symptoms.
In some cases, avoiding the trigger may be enough to prevent future skin outbreaks. You may also need medication to relieve symptoms or allergy shots to desensitize your immune system and diminish allergic reactions.
If you develop an allergic skin rash or hives, call Allergy Asthma & Immunology Institute for an evaluation. If your symptoms are severe, emergency appointments are available.
