Anaphylaxis

Anaphylaxis

Overview

Anaphylaxis is a severe, life-threatening allergic reaction. It can happen seconds or minutes after you’ve been exposed to something you’re allergic to. Peanuts or bee stings are examples. In anaphylaxis, the immune system releases a flood of chemicals that can cause the body to go into shock. Blood pressure drops suddenly, and the airways narrow, blocking your breathing. The pulse may be fast and weak, and you may have a skin rash. You may also get nauseous and vomit. Anaphylaxis needs to be treated right away with an injection of epinephrine. If it isn’t treated right away, it can be deadly.

Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as peanuts or bee stings.

Anaphylaxis causes the immune system to release a flood of chemicals that can cause you to go into shock — blood pressure drops suddenly and the airways narrow, blocking breathing. Signs and symptoms include a rapid, weak pulse; a skin rash; and nausea and vomiting. Common triggers include certain foods, some medications, insect venom and latex.

Anaphylaxis requires an injection of epinephrine and a follow-up trip to an emergency room. If you don't have epinephrine, you need to go to an emergency room immediately. If anaphylaxis isn't treated right away, it can be fatal.

Symptoms

Symptoms of anaphylaxis include hives and itchy, pale, or flushed skin. Blood pressure may be low, it may be hard to breathe, and the pulse may be weak and fast. You may get nauseous, vomit, have diarrhea, feel dizzy, and faint. Symptoms usually happen minutes after you’ve been exposed to something you’re allergic to, but they might not appear for a half hour or longer.

Anaphylaxis symptoms usually occur within minutes of exposure to an allergen. Sometimes, however, anaphylaxis can occur a half-hour or longer after exposure. In rare cases, anaphylaxis may be delayed for hours. Signs and symptoms include:

Skin reactions, including hives and itching and flushed or pale skin

Low blood pressure (hypotension)

Constriction of the airways and a swollen tongue or throat, which can cause wheezing and trouble breathing

A weak and rapid pulse

Nausea, vomiting or diarrhea

Dizziness or fainting

Causes

Anaphylaxis is caused by a severe allergic reaction. It happens when the immune system mistakes a food or substance for something that’s harmful. In response, the immune system releases a flood of chemicals to fight against it. These chemicals are what cause the symptoms of an allergic reaction. Allergy symptoms usually aren’t life-threatening, but a severe reaction can lead to anaphylaxis. The most common triggers of anaphylaxis in children are food allergies like to peanuts, milk, fish, and shellfish. In adults, stings from insects, latex, and some medications can cause anaphylaxis.

The immune system produces antibodies that defend against foreign substances. This is good when a foreign substance is harmful, such as certain bacteria or viruses. But some people's immune systems overreact to substances that don't normally cause an allergic reaction.

Allergy symptoms aren't usually life-threatening, but a severe allergic reaction can lead to anaphylaxis. Even if you or your child has had only a mild anaphylactic reaction in the past, there's a risk of more severe anaphylaxis after another exposure to the allergy-causing substance.

The most common anaphylaxis triggers in children are food allergies, such as to peanuts and tree nuts, fish, shellfish, wheat, soy, sesame and milk. Besides allergy to peanuts, nuts, fish, sesame and shellfish, anaphylaxis triggers in adults include:

Certain medications, including antibiotics, aspirin and other pain relievers available without a prescription, and the intravenous (IV) contrast used in some imaging tests

Stings from bees, yellow jackets, wasps, hornets and fire ants

Latex

Although not common, some people develop anaphylaxis from aerobic exercise, such as jogging, or even less intense physical activity, such as walking. Eating certain foods before exercise or exercising when the weather is hot, cold or humid also have been linked to anaphylaxis in some people. Talk with your health care provider about precautions to take when exercising.

If you don't know what triggers an allergy attack, certain tests can help identify the allergen. In some cases, the cause of anaphylaxis is not identified (idiopathic anaphylaxis).

Risk factors

You may be more at risk of anaphylaxis if you’ve had this reaction before or if you have allergies or asthma. Conditions like heart disease or a buildup of white blood cells can also increase your risk.

There aren't many known risk factors for anaphylaxis, but some things that might increase the risk include:

Previous anaphylaxis. If you've had anaphylaxis once, your risk of having this serious reaction increases. Future reactions might be more severe than the first reaction.

Allergies or asthma. People who have either condition are at increased risk of having anaphylaxis.

Certain other conditions. These include heart disease and an irregular accumulation of a certain type of white blood cell (mastocytosis).

Complications

An anaphylactic reaction can be life-threatening — it can stop your breathing or your heartbeat.

Prevention

The best way to prevent anaphylaxis is to stay away from substances that cause this severe reaction. Also:

Wear a medical alert necklace or bracelet to indicate you have an allergy to specific drugs or other substances.

Keep an emergency kit with prescribed medications available at all times. Your provider can advise you on the contents. If you have an epinephrine autoinjector, check the expiration date and be sure to refill the prescription before it expires.

Be sure to alert all your providers to medication reactions you've had.

If you're allergic to stinging insects, use caution around them. Wear long-sleeved shirts and pants; don't walk barefoot on grass; don't wear bright colors; don't wear perfumes, colognes or scented lotions; and don't drink from open soda cans outdoors. Stay calm when near a stinging insect. Move away slowly and don't slap at the insect.

If you have food allergies, carefully read the labels of all the foods you buy and eat. Manufacturing processes can change, so it's important to periodically recheck the labels of foods you commonly eat.

When eating out, ask how each dish is prepared, and find out what ingredients it contains. Even small amounts of food you're allergic to can cause a serious reaction.

Diagnosis

Your provider might ask you questions about previous allergic reactions, including whether you've reacted to:

Particular foods

Medications

Latex

Insect stings

To help confirm the diagnosis:

You might be given a blood test to measure the amount of a certain enzyme (tryptase) that can be elevated up to three hours after anaphylaxis

You might be tested for allergies with skin tests or blood tests to help determine your trigger

Many conditions have signs and symptoms similar to those of anaphylaxis. Your provider might want to rule out other conditions.

Treatment

During an anaphylactic attack, you might receive cardiopulmonary resuscitation (CPR) if you stop breathing or your heart stops beating. You might also be given medications, including:

Epinephrine (adrenaline) to reduce the body's allergic response

Oxygen, to help you breathe

Intravenous (IV) antihistamines and cortisone to reduce inflammation of the air passages and improve breathing

A beta-agonist (such as albuterol) to relieve breathing symptoms

What to do in an emergency

If you're with someone who's having an allergic reaction and shows signs of shock, act fast. Look for pale, cool and clammy skin; a weak, rapid pulse; trouble breathing; confusion; and loss of consciousness. Do the following immediately:

Check the person's pulse and breathing and, if necessary, administer cardiopulmonary resuscitation (CPR) or other first-aid measures.

Using an autoinjector

Many people at risk of anaphylaxis carry an autoinjector. This device is a combined syringe and concealed needle that injects a single dose of medication when pressed against the thigh. Replace epinephrine before its expiration date, or it might not work properly.

Using an autoinjector immediately can keep anaphylaxis from worsening and could save your life. Be sure you know how to use the autoinjector. Also, make sure the people closest to you know how to use it.

Long-term treatment

If insect stings trigger an anaphylactic reaction, a series of allergy shots (immunotherapy) might reduce the body's allergic response and prevent a severe reaction in the future.

Unfortunately, in most other cases there's no way to treat the underlying immune system condition that can lead to anaphylaxis. But you can take steps to prevent a future attack — and be prepared if one occurs.

Try to stay away from your allergy triggers.

Carry self-administered epinephrine. During an anaphylactic attack, you can give yourself the drug using an autoinjector.

Type of Doctor Department :An allergist