Hives (Urticaria) And Angioedema Causes, Types, Symptoms, Diagnosis, Treatment, Prevention, Home Remedies

Hives (Urticaria) And Angioedema Causes, Types, Symptoms, Diagnosis, Treatment, Prevention, Home Remedies

Hives (Urticaria) And Angioedema Overview

Hives and angioedema are related because they are similar reactions to the same basic cause, a chemical called histamine. In most cases, histamine is a byproduct of the body’s specialized mast cells as they go about their job of destroying allergens, which are any substances that cause allergic reactions. Fighting allergens is not the only way that histamine is produced, however. Irritation caused by sunlight, some medications, and unknown sources can make mast cells release histamine, too.

Whatever the reason for its release, histamine produces hives and angioedema by dilating the small blood vessels in the skin and causing fluid to leak from them. This in turn generates swelling. It also can stimulate gastric acid secretion and cause certain smooth muscles to contract.

Hives—or more technically, urticaria—are pale red welts that can appear anywhere on the body in splotches as small as a pencil eraser and as large as a dinner plate. These splotches sometimes join together to form larger areas known as plaques. Whether large or small, hives and plaques often fade within a few hours, but can last three days or longer.

In general, angioedema lasts longer than urticaria, but the swelling usually goes away within 24 hours. Symptoms include deep swelling around the eyes and lips, and sometimes swelling of the genitals, hands, and feet. Occasionally, severe and prolonged swelling of the tissue can be disfiguring. In rare instances, angioedema of the throat, tongue, or lungs can block the airways, making breathing difficult and endangering the life of the victim. Hives, also known as urticaria, are an outbreak of swollen, pale red bumps, patches, or welts on the skin that appear suddenly -- either as a result of allergies, or for other reasons.

Hives usually cause itching, but may also burn or sting. They can appear anywhere on the body, including the face, lips, tongue, throat, or ears. Hives vary in size (from a pencil eraser to a dinner plate), and may join together to form larger areas known as plaques. They can last for hours, or up to several days before fading.

Angioedema is similar to hives, but the swelling occurs beneath the skin instead of on the surface. Angioedema is characterized by deep swelling around the eyes and lips and sometimes of the genitals, hands, and feet. It generally lasts longer than hives, but the swelling usually goes away in less than 24 hours.

Occasionally, severe, prolonged tissue swelling can be disfiguring. Rarely, angioedema of the throat, tongue, or lungs can block the airways, causing difficulty breathing. This may become life threatening.

Read more: Hodgkin's Disease Causes, Symptoms and Treatment

Hives (Urticaria) And Angioedema Causes

Hives and angioedema are caused by triggers that produce a skin or tissue reaction by stimulating certain cells (mast cells) to release histamine and other chemicals into your bloodstream.

Sometimes it's not possible to pinpoint the cause of hives and angioedema, especially when these conditions become chronic or recur.

Allergic reactions are one common trigger of acute hives and angioedema. Common allergens include:

  • Foods. Many foods can trigger reactions in people with sensitivities. Shellfish, fish, peanuts, tree nuts, eggs and milk are frequent offenders.
  • Medications. Almost any medication may cause hives or angioedema. Common culprits include penicillin, aspirin, ibuprofen (Advil, Motrin, others), naproxen (Aleve, others) and blood pressure medications.
  • Other allergens. Other substances that can cause hives and angioedema include pollen, animal dander, latex and insect stings.

Additional triggers Hives (Urticaria) And Angioedema include:

  • Environmental factors. In some people, environmental factors can stimulate release of histamine. Examples include heat, cold, sunlight, water, pressure on the skin, emotional stress and exercise.
  • Dermatographia (also known as dermographia). The name of this condition literally means "skin writing." Stroking or scratching the skin results in raised red lines in the same pattern as the pressure.
Hives and angioedema also occasionally occur in response to blood transfusions, immune system disorders such as lupus, some types of cancer such as lymphoma, certain thyroid conditions, and infections with bacteria or viruses such as hepatitis, HIV, cytomegalovirus or Epstein-Barr virus.

Hereditary angioedema is a rare inherited (genetic) form of the condition. It's related to low levels or abnormal functioning of certain blood proteins (C1 inhibitors) that play a role in regulating how your immune system functions.

Types of urticaria and angioedema

Doctors usually classify hives and angioedema according to the following categories:

Acute urticaria and/or angioedema

Acute urticaria is a case of hives that lasts less than six weeks. The most common causes are foods, medications, latex, or infections, but insect bites and internal disease can be responsible too. The most common foods that trigger hives are nuts, fish, tomatoes, and fresh berries. Medications that can cause hives and angioedema include aspirin, other nonsteroidal anti-inflammatory medications such as ibuprofen, high-blood-pressure medications (ACE inhibitors), and painkillers such as codeine.

Chronic urticaria and/or angioedema

Chronic urticaria and angioedema lasts more than six weeks. The cause of this type of reaction tends to be much more difficult to identify than the cause of the acute kind. For this reason, it is often not found. In fact, the cause of chronic urticaria remains unknown for more than 80 percent of cases.

Physical urticaria

Physical urticaria is a case of hives caused by direct physical stimulation of the skin from exposure to cold, heat, sun, vibration, pressure, sweating, exercise, and other sources. These hives usually occur at the site of the stimulation and rarely appear elsewhere. Most of outbreaks in this class appear within one hour after exposure.


Hives that form after firmly stroking or scratching the skin. These hives can also occur along with other forms of urticaria.

Hereditary angioedema

This is painful swelling of tissue. It is passed on through families.

Hives (Urticaria) And Angioedema Symptoms and Signs

Hives (Urticaria) symptoms

Hives is a rash of smooth, raised, pink or reddish bumps of different sizes, called wheals. Hives appear suddenly. The wheals look somewhat like mosquito bites. They may cover all or part of the body and are usually very itchy.

Hives usually appear first on the covered areas of the skin such as the trunk and upper parts of the arms and legs.

Wheals appear in batches. Each wheal may last from a few minutes to six hours. As wheals disappear, new ones form. A case of hives usually lasts at most a few days.

Hives are usually patchy at first, but the patches may run together until the hives cover most of the body.

The patches can be small or large. They are usually irregular in shape. Often, the patches have clearing of the redness in the center with a red halo or flare at the edges.

The itching is often very intense.

Hives are characterized by blanching, which means that the redness goes away and the area turns pale when pressure is applied.

Dermographism may be present. Dermographism refers to the appearance of reddened areas like hives that appear after light scratching of the skin.

Angioedema symptoms

Angioedema is related to hives but has a different appearance. Angioedema describes marked swelling, usually around the eyes and mouth. It may also involve the throat, tongue, hands, feet, and/or genitals.

The skin may appear normal, without hives or other rash.

The eyes may appear swollen shut.

The swellings usually do not itch but may be painful or burning.

The swellings may not be symmetrical (the same on both sides of the body).

Like hives, the swelling of angioedema can go away on its own.

Other, more severe allergic reactions may occur with hives or angioedema 

A reaction may start with hives or angioedema and then progress rapidly to more serious symptoms. The most serious reactions, which can be life-threatening emergencies, are called anaphylactic reactions. The symptoms of an anaphylactic reaction include the following:

  • Swelling of the face, tongue, or throat
  • Wheezing, a raspy sound when you breathe
  • Difficulty breathing
  • Difficulty swallowing
  • Tightness in the throat or chest
  • Rapid or irregular heart beat
  • Dizziness or faintness
  • Loss of consciousness
  • Respiratory stridor, to and fro breathing that is strained in the throat

The dizziness, faintness, and loss of consciousness are caused by dangerously low blood pressure, also called shock.

When to see a doctor 

Mild hives and angioedema usually aren't life-threatening. You can usually treat mild cases at home.

See your doctor if:

  • Your hives or angioedema doesn't respond to treatment
  • You have severe discomfort
  • Your symptoms continue for more than a few days
Seek emergency care if:

  • You feel lightheaded
  • You have severe chest tightness or trouble breathing
  • You feel your throat is swelling

How Are Hives (Urticaria) And Angioedema Diagnosed?

Your doctor will need to ask many questions in an attempt to find the possible cause of hives or angioedema. Since there are no specific tests for hives -- or the associated swelling of angioedema -- testing will depend on your medical history and a thorough examination by your primary care doctor, allergist, immunologist, or dermatologist.

Skin tests may be performed to determine the substance that you are allergic to. Routine blood tests are done to determine if a system-wide illness is present.

What Is the Treatment for Hives (Urticaria) And Angioedema?

The best treatment for hives and angioedema is for your doctor to identify the trigger and then for you to avoid it. Identifying triggers, however, is not an easy task. Your doctor will need to ask you many questions and perform some tests.

Because there are no specific tests for hives or angioedema, the kinds of tests ordered will depend upon your medical history and a thorough examination by one or more specialists. Skin tests may be performed to determine the substance to which you are allergic. Blood tests are done routinely to rule out a systemic illness as the cause of your body’s release of histamine.

If your condition is persistent, your doctor will probably prescribe an antihistamine to provide you with relief from the symptoms. These medications work best when taken on a regular schedule to prevent the swelling. Your doctor may prescribe oral corticosteroids if antihistamines do not work well. For severe outbreaks, an injection of epinephrine (adrenaline) or a cortisone-based medication may be needed.

While you’re waiting for the hives and swelling to disappear, doing the following might help to relieve the symptoms:

  • Avoid hot water; use lukewarm water instead.
  • Use gentle, mild soap.
  • Apply cool compresses or wet cloths to the afflicted areas.
  • Try to work and sleep in a cool room.
  • Wear loose-fitting, lightweight clothes.

Hives (Urticaria) And Angioedema Prevention

To lower your likelihood of experiencing hives or angioedema, take the following precautions:

  • Avoid known triggers. These may include certain foods or medications, or situations such as temperature extremes, that have triggered past allergic attacks.
  • Reducing emotional and physical stress may help. In rare cases, you may need to take antihistamines or other medicines for an extended time to prevent further hives or swelling.
  • Keep a diary. If you suspect foods are causing the problem, keep a food diary. Be aware that some foods may contain ingredients that are listed by less common names on the label.

Home Remedies for Hives (Urticaria) And Angioedema

Try to identify and avoid substances that irritate your skin or that cause an allergic reaction. These can include foods, medications, pollen, pet dander, latex and insect stings.

Use an over-the-counter antihistamine. A nonprescription oral antihistamine, such as loratadine (Claritin), cetirizine (Zyrtec) or diphenhydramine (Benadryl, others) may help relieve itching.

Apply cool, wet compresses. Covering the affected area with bandages and dressings can help soothe the skin and prevent scratching.

Take a comfortably cool bath. To relieve itching, sprinkle the bath water with baking soda, uncooked oatmeal or colloidal oatmeal — a finely ground oatmeal that is made for the bathtub (Aveeno, others). Avoid hot baths or showers.

Wear loose, smooth-textured cotton clothing. Avoid clothing that's rough, tight, scratchy or made from wool. This will help you avoid irritation.

Avoid direct sunlight.

Avoid strenuous activity or anything that might cause sweating.

Try to relax and reduce stress.

If at all possible, you or your companion should be prepared to tell medical personnel what medications you take and your allergy history.

Hives and Angioedema Prognosis

Hives and angioedema may be very uncomfortable but will not cause serious harm.

The hives will not leave scars.

Most people do well with treatment.

Hives and angioedema usually will last only a few hours to a few days. Chronic hives lasts longer than six weeks but is rare.