anngioedema.doc

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http://www.mayoclinic.com/health/hives-and-angioedema/DS00313/DSECTION=2

Introduction

Hives also known as urticaria are raised, red, itchy welts (wheals) of various sizes that appear anddisappear on your skin. Angioedema, a similar swelling, causes large welts deeper in your skin, especially

near your eyes and lips. A more serious condition hereditary angioedema (HAE) is an uncommon,inherited disorder, which can cause sudden, severe and rapid swelling of your face, arms, legs, hands, feet,genitalia, digestive tract and airway.

As many as one in five people experiences acute hives or angioedema at one time or another. HAE, on theother hand is rare.

In most cases, hives and angioedema are harmless and don't leave any lasting marks, even withouttreatment. The most common treatment for hives and angioedema is antihistamine medications. Seriousangioedema can be life-threatening if swelling causes your throat or tongue to block your airway and leadsto loss of consciousness.

Signs and symptoms

Hives can be either acute or chronic. By definition, acute hives can last from less than a day to up to sixweeks, whereas chronic hives last more than six weeks sometimes occurring for months to years at atime. Angioedema and hives can occur at the same time.

Hives are raised, red bumps of various sizes that appear and disappear on your skin. They're often itchy andmay look similar to mosquito bites. Hives tend to occur in batches.

Angioedema is similar to hives but occurs deeper in the skin. Signs and symptoms of angioedema includelarge welts or swelling of the skin that may occur in the following locations:

Especially near your eyes and lips

On your hands

On your feet On your genitalia

Inside your throat

Signs and symptoms of hereditary angioedema include:

Sudden and severe swelling of your face, arms, legs, hands, feet, genitalia, digestive tract andairway

Abdominal cramping as a result of digestive tract swelling

Difficulty or obstructed breathing due to swelling of your airway

Causes

The lesions of hives and angioedema are caused by inflammation in the skin. In some cases, hives andangioedema are triggered when certain cells (mast cells) release histamine and other chemicals into yourbloodstream and skin.

Allergic reactions to medications or foods can cause acute hives or angioedema. Many allergens have beenidentified. Examples include:

Foods. Many foods can cause problems in sensitive people, but shellfish, fish, nuts, eggs andmilk are frequent offenders.
http://www.mayoclinic.com/health/hives-and-angioedema/DS00313/DSECTION=2http://www.mayoclinic.com/health/hives-and-angioedema/DS00313/DSECTION=2


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Medications. Almost any medication may cause hives or angioedema; common culprits includeantibiotics, aspirin, ibuprofen (Advil, Motrin, others) and blood pressure medications.

Other allergens. Other substances that can cause hives and angioedema include direct contactwith pollen, animal dander, latex and insect stings.

Additional triggers that may produce hives or angioedema include:

Physical factors. Environmental factors also can result in the release of histamine withsubsequent hives or angioedema in some people. Examples of these factors include heat, cold,sunlight, water, pressure on the skin, emotional stress and exercise.

Dermatographism. The name of this condition literally means "write on the skin." When pressureis applied to the skin or the skin is scratched, raised lines appear on those areas due to histamine-based angioedema that leads to swelling beneath the skin.

In addition to these triggers, hives and angioedema sometimes may occur in response to your body'sproduction of antibodies. Some examples of situations in which this might occur include blood transfusions;immune system disorders, such as lupus or cancer; certain thyroid disorders; and infections, such ashepatitis, or even a cold.

Hereditary angioedema is an inherited form of angioedema and is related to low levels or abnormalfunctioning of certain blood proteins (C1 inhibitors). These inhibitors play a role in regulating how yourimmune system functions.

Risk factors

You may be at greater risk of hives and angioedema if you:

Have had hives or angioedema before

Have had other allergic reactions

Have a disorder associated with hives and angioedema, such as lupus, lymphoma or thyroiddisease

Have a family history of hives, angioedema or hereditary angioedema

When to seek medical advice

Mild hives and angioedema usually aren't life-threatening, and often you can treat hives and angioedema athome. However, seek emergency care if you feel lightheaded, have difficulty breathing, or if you feel yourthroat is swelling. See your doctor if your hives don't respond to treatment or if they continue to appear formore than a couple of days.

Screening and diagnosis

It's sometimes impossible to determine the cause of hives or angioedema. Your doctor will begin by askingyou about your medical history. This may include asking you to create a detailed diary of exposure to

possible irritants. It's important to tell your doctor about all medications you take, including over-the-counter(OTC) drugs and herbal remedies, even if you don't take them every day. Your doctor may also want toconduct allergy tests, such as skin tests.

If your doctor suspects HAE, he or she may ask for blood tests to check for levels and function of specificblood proteins. If your doctor suspects allergy to food, latex, animal dander, pollen or medication, he or shemay recommend allergy skin or blood tests.

Complications


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Hives and angioedema can cause itching and discomfort. In more serious cases when swelling occursinside your mouth or throat complications can include difficulty breathing or loss of consciousness.

Anaphylactic shock (anaphylaxis) is a serious allergic reaction involving your heart or lungs. Your bronchialtubes narrow, it's difficult to breathe, and your blood pressure drops, causing dizziness and perhaps loss ofconsciousness or even death. Anaphylactic shock occurs rapidly, and requires immediate medical care.

Treatment

If your symptoms are mild, you may not need treatment. The standard treatment for hives and angioedemais antihistamines, which block the symptom-producing release of histamine. These include:

Nonprescription medications

Diphenhydramine (Benadryl, others)

Chlorpheniramine (Chlor-Trimeton, others)

Clemastine (Tavist, others)

Loratadine (Alavert, Claritin)

Antihistamines such as diphenhydramine, chlorpheniramine and clemastine may cause drowsiness.Loratadine usually doesn't cause drowsiness.

Prescription medications

Desloratadine (Clarinex)

Fexofenadine (Allegra)

Cetirizine (Zyrtec)

Hydroxyzine (Atarax, Vistaril)

Occasionally for severe hives or angioedema, doctors may prescribe an oral corticosteroid drug such asprednisone which can help lessen swelling, redness and itching.

Treatment for HAEAlthough useful in treating hives and angioedema, these medications are often ineffective in treatinghereditary angioedema. Medications used specifically to treat HAE on a long-term basis include certainandrogens, such as danazol (Danocrine), that help regulate levels of blood proteins. Additionally, clinicaltrials testing new medications to treat HAE are ongoing.

Emergency situationsFor a severe attack of hives or angioedema, you may need an emergency injection of adrenaline(epinephrine) and a trip to the emergency room. If you have repeated attacks, despite treatment, your doctormay prescribe and instruct you how to use adrenaline to carry with you for use in emergencysituations.

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 astemperature extremes, that have triggered past allergic attacks.

Keep a diary. If you suspect foods of causing the problem, keep a food diary. Be aware thatsome foods may contain ingredients that are listed by less common names on the label.


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Self-care

If you're experiencing mild hives or angioedema, these tips may help relieve your symptoms:

Avoid irritating affected areas.

Take cool showers.

Apply cool compresses.

Wear loose, light clothing.

Minimize vigorous activity, which can release more irritants into your skin.

Use over-the-counter antihistamines to help relieve the itching.

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