Signs and Symptoms

• Itching (often the first symptom), redness, hives, swelling, sweating
• Swelling in the nose or throat, wheezing, difficulty speaking, trouble breathing, chest tightness
• Abnormal heart rate or rhythm, shock, heart attack
• Stomach cramps, nausea, vomiting, diarrhea
• Dizziness, fainting

What Causes It?

Anaphylaxis occurs when your immune system overreacts to an allergen. Your body releases substances to protect you from the allergen. Instead those same substances cause:

• Your blood pressure to drop suddenly
• Your airways to constrict so that you have trouble breathing

Many substances can cause anaphylaxis. Sometimes the cause isn't known. Common triggers include:

• Antibiotics (especially penicillin)
• Aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen), and prescription opiate pain medications (such as codeine)
• Other substances used in medical procedures, including radiocontrast media, transfusion products, drugs used for anesthesia
• Foods, such as nuts, shellfish, milk, eggs, and berries
• Insect bites or stings
• Egg-based vaccines
• Latex (as in condoms, rubber gloves)
• Exercise and a cold may trigger non-allergic anaphylaxis

Who Is Most At Risk?

Anaphylaxis is rare. The incidence of anaphylaxis may be higher in the first two decades of life. The following factors may increase your risk for anaphylaxis:

• Known allergies
• Cardiovascular disease
• Substance abuse
• Asthma and other respiratory diseases
• Initial exposure to the allergen by injection (intravenous medication)
• Frequent exposure to the allergen, particularly if exposure is followed by a long delay and then a re-exposure

What to Expect at Your Provider's Office

Your health care provider will perform an exam. You will be asked about any contact you may have had with possible allergens (such as food, drugs, and insect stings). Blood or urine tests, allergy tests, or other tests may also be conducted.

Treatment Options

Prevention

• Avoid substances that have triggered a previous allergic response.
• If you have allergies, or suspect you do, see a specialist to be tested.
• Take medicines by mouth instead of by injection whenever possible.
• If you have a history of anaphylaxis, your doctor should teach you and your caregivers about using self-injectable epinephrine. You should keep a syringe loaded with adrenaline (epinephrine). Inject yourself right away if any symptoms or signs of anaphylaxis occur. In addition, wear a Medic Alert bracelet. This will alert others that you have a history of this condition.

Treatment Plan

Get emergency medical care immediately to maintain breathing, blood pressure, and heart function, and to reverse the reaction. Your doctor may recommend oral desensitization to foods or medications to prevent future episodes.

Drug Therapies

You should receive epinephrine right away. Once at the hospital, your health care provider may give you additional drugs, including antihistamines and corticosteroids, to control symptoms and prevent delayed relapse.

Surgical and Other Procedures

For breathing trouble, health care providers may need to open the airway with an endotracheal tube and possibly connect a ventilator. Other procedures may be needed to stabilize blood pressure.

Complementary and Alternative Therapies

Anaphylaxis always requires emergency medical care. It should not be treated with alternative therapies. Some CAM therapies may help lessen the severity of certain allergies, but they should not be used to treat anaphylaxis. However, some herbs and supplements -- just like prescription drugs -- can cause allergic reactions, including anaphylaxis. If you have allergies, talk to your health care provider before taking any herbs or supplements.

The following nutrients may help support your immune system and reduce allergic reactions. However, there is no scientific evidence that they help prevent anaphylaxis and should never be used as treatment for anaphylaxis. Complimentary therapies should never be used as a substitute for conventional medicine when either treating or trying to prevent anaphylaxis. People with known triggers for anaphylaxis should avoid those triggers, even if they're using CAM therapies.

• Quercetin is a flavonoid found in many plants. Quercetin has anti-inflammatory and anti-oxidant effects in vitro, and may also help stabilize mast cells. Based on these effects, quercetin or quercetin chalcone may help reduce allergic reactions. Quercetin may interact with many other drugs. Pregnant women should not take quercetin. If you have liver or kidney problems, speak to your doctor before taking quercetin.
• Vitamin C -- Supports immune system function. It also enhances the effect of quercetin. No data supports vitamin C as treatment for allergic reactions.
• Vitamin D -- Some recent evidence links vitamin D deficiency with allergic diseases. However there is no evidence that vitamin D supplementation would help prevent or reduce allergic reactions.
• Probiotics -- Lactobacilli and bifidobacteria probiotic products are sometimes used for children with allergic diseases. Epidemiologic studies link intestinal probiotic bacteria with protection from allergic disease. However, no clinical study currently supports probiotics as prevention or treatment for allergic reactions.

Some herbs may help support your immune system. Other may reduce the frequency or severity of allergic reactions. However, there is no evidence that any herbs can prevent or treat anaphylaxis. Anaphylaxis is a medical emergency. Never use herbs to treat it. Do not take herbs if you are pregnant or nursing, unless you are under the supervision of a qualified practitioner. Tell your health care providers about any herbal medicines you are planning to use.

• Skullcap (Scutellaria baicalensis) -- May have antihistamine properties and was shown to decrease food allergy in animal studies. Do not use Skullcap if you are pregnant or nursing. Skullcap can potentially interact with a variety of medications. Speak with your physician.
• Licorice (Glycyrrhiza glabra) -- Has been used traditionally to support the immune system and may have antihistamine properties. Licorice should only be used under the direction of a trained physician. Used in large amounts and for a long time, licorice can cause hypertension. Pregnant women should avoid licorice supplements or large amounts of licorice as food. Do not take licorice if you have high blood pressure, heart disease, kidney disease, low potassium, sexual dysfunction (in men), history of hormone-sensitive cancers, or are anticipating having surgery within 2 weeks. Licorice can interact with several medications, including digitalis, diuretics, antihypertensives, and others. Speak with your health care provider.
• Stinging nettle (Urtica dioica) -- May have anti-inflammatory and anti-allergic properties, however scientific evidence is insufficient to support it as treatment for allergic reactions. Stinging nettle may interact with several medications. Talk to your doctor or pharmacist if you have kidney problems or  diabetes before taking stinging nettle.

Several studies suggest that medicinal plants traditionally used in Asia to prevent or treat allergic reactions may help indeed have some anti-allergic effects in vitro or in experimental animal models of allergic reactions. These herbal remedies include sweet chestnut tree (Castanea crenata), spreading sneezeweed (Centipeda minima), Asian rose (Rosa davurica), Hardy orange (Poncirus trifoliata), Japanese catnip, and others.

Researchers have also tested combinations of specific herbs in animals, which show some signs of preventing anaphylaxis. One such combination of 9 traditional Chinese herbs, termed food allergy herbal formula-2 (FAHF-2) was effective in preventing peanut allergy in mice. However, no herb or herb combination has been demonstrated as effective in any human study. Herbs may also have dangerous side effects, interact with medications, or even cause allergic reactions themselves. Before taking any herbs for allergies, you should consult your provider, especially if you have a chronic condition or are pregnant.

Some people use homeopathic remedies for allergic reactions or allergic diseases. However there is no research showing effectiveness of homeopathy in preventing or treating anaphylaxis. Anaphylaxis requires emergency medical treatment.

Acupuncture has been used to support the immune system and to relieve symptoms of seasonal allergies, as well as to lessen chronic allergies, asthma and atopic dermatitis. Acupuncture is generally considered safe and well tolerated. However, acupuncture should never be used to treat anaphylaxis, which requires immediate medical attention.

Prognosis/Possible Complications

Without proper treatment, anaphylaxis can be deadly. However, most people who receive proper treatment do well. An episode of anaphylaxis puts you in the high risk group for recurrence. Recurrences tend to occur less and go away with time, even if the allergen is unknown. The likelihood of recurrence is higher if serious symptoms are present during the first episode.

Following Up

You may need to stay in the hospital for 24 hours to make sure no new symptoms occur. For a severe reaction, your doctor may monitor heart function or admit you to the intensive care unit.

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