What type of allergies cause hives

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Hives are a red, raised, itchy skin rash that is sometimes triggered by an allergen. An allergen is something that produces an allergic reaction. When an allergic reaction occurs, the body releases a protein called histamine.

When histamine is released, the tiny blood vessels known as capillaries leak fluid. The fluid accumulates in the skin and causes a rash. Hives affect around 20 percent of people at some time in their life. Urticaria occurs when the body reacts to an allergen and releases histamine and other chemicals from under the surface of the skin. The histamine and chemicals cause inflammation and fluid to accumulate under the skin, causing wheals.

Treatment for acute urticaria includes non-sedating antihistamines taken regularly for several weeks. Antihistamines, such as cetirizine or fexofenadine, help by blocking the effects of histamines and reducing the rash and stopping the itching.

Various antihistamines can be purchased in pharmacies or online. Some antihistamines cause drowsiness, especially if the user also consumes alcohol. Some are not suitable during pregnancy unless prescribed by a doctor. Patients with angioedema may need to see an allergist, an immunologist, or a dermatologist. Angioedema can cause potentially serious breathing difficulties. If there is swelling of the tongue or lips, or if breathing becomes difficult, the doctor may prescribe an epinephrine auto-injector, for example, EpiPen, in case of emergencies.

Omalizumab, or Xolair , is an injectable drug that blocks immunoglobin E, a substance that plays a role in allergic responses. It can reduce symptoms of chronic idiopathic urticaria, a type of hives of unknown origin that can last for months or years. Chronic hives can lead to severe discomfort, distress, and possibly depression.

Stress , too, can aggravate hives, creating a vicious cycle. Patients who experience symptoms of depression should speak to a doctor. Swellings, known as wheals, appear as a rash on the skin. They are usually pink or red, with an oval or round shape. They can range from a few millimeters to several inches across. They can be extremely itchy, and they have a red flare around them.

The wheals usually occur in batches, frequently on the face or the extremities, including the arms, hands, fingers, legs, feet, and toes. When you have an allergic reaction to a substance, your body releases histamine and other chemicals into the blood. This causes itching, swelling, and other symptoms. Hives are a common reaction. People with other allergies, such as hay fever, often get hives.

Angioedema is swelling of the deeper tissue that sometimes occurs with hives. Like hives, angioedema can occur on any part of the body. When it occurs around the mouth or throat, the symptoms can be severe, including airway blockage. If you have a history of an allergy causing hives, 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 hives. Treatment may not be needed if the hives are mild. They may disappear on their own. To reduce itching and swelling:. If your reaction is severe, especially if the swelling involves your throat, you may need an emergency shot of epinephrine adrenaline or steroids. Hives in the throat can block your airway, making it difficult to breathe. When the condition lasts longer than 6 weeks, it is called chronic hives.

Usually no cause can be found. Most chronic hives resolve on their own in less than 1 year. Call your provider if the hives are severe, uncomfortable, and do not respond to self-care measures. Dinulos JGH. Urticaria, angioedema, and pruritus. In: Dinulos JGH, ed. They can be small and round, ring-shaped, or large and of random shape. Hives are itchy, and they tend to appear in batches on the affected part of the body. They can grow larger, change shape, and spread. Hives may disappear or reappear over the course of the outbreak.

Individual hives can last anywhere from half an hour to a day. Hives may turn white when pressed. Sometimes the hives may change shape or form together and create a larger, raised area. Hives can occur in a variety of places on the body. Call or seek medical attention immediately if you develop a hive outbreak around your throat or on your tongue or have trouble breathing along with hives. The most common causes of hives are allergic reactions.

These can be caused by any allergen you might be sensitive to, including:. Mild cases of hives caused by allergies are typically treated with long- or short-term allergy medications and avoidance of the trigger. Anaphylaxis is a severe, life-threatening allergic reaction. In this condition, hives are often accompanied with breathing difficulties, nausea or vomiting, severe swelling, and dizziness. Call immediately if you suspect anaphylaxis. Also called chronic urticaria, this condition is marked by recurring hives that can interfere with your lifestyle.

According to the Mayo Clinic , these can last between six weeks and several months or years. While not life-threatening, this form of hives can be uncomfortable and difficult to treat. They may also be a symptom of an underlying health problem, such as:. This form of acute hives is considered mild. Excessive scratching or continuous pressure on the skin causes it. Dermatographism usually clears up on its own in a short period of time without treatment. Sometimes changes in temperature can induce hives in people who are sensitive to such changes.

Cold-induced hives may occur from cold water or air exposure, while body heat from physical activity may cause exercise-induced hives. Exposure to sunlight or tanning beds may also bring about solar hives in some people. Both viral and bacterial infections can cause hives. Common bacterial infections causing hives include urinary tract infections and strep throat. Viruses that cause infectious mononucleosis, hepatitis, and colds often cause hives. The first step in getting treatment is to figure out if you actually have hives.