Anaphylaxis symptoms usually occur within minutes of exposure to an allergen. Sometimes, however, anaphylaxis can occur a half-hour or longer after exposure. Anaphylaxis symptoms include:
- Skin reactions, including hives along with itching, and flushed or pale skin (almost always present with anaphylaxis)
- A feeling of warmth
- The sensation of a lump in your throat
- 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
When to see a doctor
Seek emergency medical help if you, your child or someone else you're with has a severe allergic reaction.
If the person having the attack carries an epinephrine autoinjector (such as an EpiPen or EpiPen Jr), give him or her a shot right away. Even if symptoms improve after an emergency epinephrine injection, a visit to the emergency department is still necessary to make sure symptoms don't return.
Make an appointment to see your doctor if you or your child has had a severe allergy attack or any signs and symptoms of anaphylaxis in the past.
The diagnosis and long-term management of anaphylaxis are complicated, so you'll probably need to see a doctor who specializes in allergies and immunology.
Your 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 shouldn't cause an allergic reaction. When this occurs, the immune system sets off a chemical chain reaction, leading to allergy symptoms. Normally, allergy symptoms aren't life-threatening. But some people have a severe allergic reaction that can lead to anaphylaxis. Even if you or your child has had only a mild anaphylactic reaction in the past, there's still a risk of more severe anaphylaxis.
A number of allergens can trigger anaphylaxis, depending on what you're allergic to.
Common anaphylaxis triggers include:
- Certain medications, especially penicillin
- Foods, such as peanuts, tree nuts (walnuts, pecans, almonds, cashews), wheat (in children), fish, shellfish, milk and eggs
- Insect stings from bees, yellow jackets, wasps, hornets and fire ants
Less common causes of anaphylaxis include:
- Medications used in anesthesia
Anaphylaxis symptoms are sometimes caused by aspirin and other drugs — such as ibuprofen (Advil, Motrin, others) and naproxen (Aleve, Midol Extended Relief) — and the intravenous (IV) contrast used in some X-ray imaging tests. Although similar to allergy-induced anaphylaxis, this type of reaction isn't triggered by allergy antibodies.
Anaphylaxis triggered by exercise is not common and varies from person to person. In some people, aerobic activity, such as jogging, triggers anaphylaxis. In others, less intense physical activity, such as walking, can trigger a reaction. Eating certain foods before exercise or exercising when the weather is hot, cold or humid also has been linked to anaphylaxis in some people. Talk with your doctor about any precautions you should take when exercising.
If you don't know what triggers your allergy attack, your doctor may do tests to try to identify the offending allergen. In some cases, the cause of anaphylaxis is never identified. This is known as idiopathic anaphylaxis.
There aren't many known risk factors for anaphylaxis, but some things that may increase your risk include:
- A personal history of anaphylaxis. If you've experienced anaphylaxis once, your risk of having this serious reaction increases. Future reactions may be more severe than the first reaction.
- Allergies or asthma. People who have either condition are at increased risk of having anaphylaxis.
- A family history. If you have family members who've experienced exercise-induced anaphylaxis, your risk of developing this type of anaphylaxis is higher than it is for someone without a family history.
An anaphylactic reaction can be life-threatening when a severe attack occurs; it can stop breathing or stop your heartbeat. In this case, you'll need cardiopulmonary resuscitation (CPR) and other emergency treatment right away.
The best way to prevent anaphylaxis is to avoid substances that you know cause this severe reaction. Follow these steps:
- Wear a medical alert necklace or bracelet to indicate if you have an allergy to specific drugs or other substances.
- Alert your doctor to your drug allergies before having any medical treatment. If you receive allergy shots, always wait at least 30 minutes before leaving the clinic so that you can receive immediate treatment if you have a severe reaction after the allergy shot.
- Keep a properly stocked emergency kit with prescribed medications available at all times. Your doctor can advise you on the appropriate contents. This may include an epinephrine autoinjector. Make sure your autoinjector has not expired; these medications generally last 18 months.
- If you're allergic to stinging insects, exercise caution when they're nearby. Wear long-sleeved shirts and pants and don't wear sandals or walk barefoot in the grass. Avoid bright colors and don't wear perfumes or colognes. Stay calm if you are near a stinging insect. Move away slowly and avoid slapping at the insect.
- If you have specific 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 about ingredients in the food, and ask about food preparation because even small amounts of the food that you're allergic to can cause a serious reaction.