Anaphylaxis is a sudden, severe, potentially fatal, systemic allergic reaction that can involve various areas of the body (such as the skin, respiratory tract, gastrointestinal tract, and cardiovascular system). Symptoms occur minutes to two hours after contact with the allergy-causing substance, but in rare instances may occur up to four hours later. Anaphylactic reactions can be mild to life-threatening. Anyone with asthma, eczema, or hay fever is at greater relative risk of experiencing anaphylaxis.
Common causes of anaphylaxis include food, medication, insect stings and latex. Other less common causes include food-dependent exercise-induced anaphylaxis and idiopathic anaphylaxis.
Peanuts, tree nuts (walnuts, cashews, etc.), shellfish, fish, mild, and eggs commonly cause anaphylactic reactions. Only a trace amount of a problem food can cause a reaction in some individuals.
Strict avoidance of the allergen is necessary for avoiding a severe reaction. Read food labels for every food each and every time you eat it. Ask questions about ingredients and preparation methods when eating away from home.
Anaphylactic reactions to medication will typically occur within an hour after taking the drug however, reactions may occur several hours later. If you experience symptoms of an allergic reaction after taking medication, speak to your doctor. If symptoms are severe, or resemble anaphylaxis, get emergency medical help immediately.
Honeybees, bumblebees, yellow jackets, hornets, wasps, fire ants, and harvester ants are the most common causes of insect stings in the United States. The symptoms of anaphylactic reactions to insect stings usually occur within minutes of the sting.
To minimize the risk of an insect sting, avoid brightly colored clothing and/or scented cosmetics, perfumes, etc., avoid walking barefoot, use caution when cooking outdoors, and keep insecticide handy when working outdoors.
Latex allergy is most commonly diagnosed in individuals who are exposed to latex frequently, such as those employed in the healthcare or rubber industry fields, and in children with spina bifida and other congenital disease requiring multiple surgeries. Some individuals with latex allergy will also develop reactions when eating foods that cross-react with latex. These foods commonly include bananas, kiwi, avocados, and European chestnuts; and less commonly include potatoes, tomatoes, peaches, plums, cherries, and other pitted fruits.
Food-Dependent Exercise-Induced Anaphylaxis
Food-dependent exercise-induced anaphylaxis is very rare and occurs only when an individual eats a specific food and exercises within three to four hours after eating. Individuals experiencing this type of reaction typically have asthma and other allergic conditions. Although any food may contribute to this form of anaphylaxis, foods that have been reported include wheat, shellfish, fruit, milk, celery, and fish.
Idiopathic Anaphylaxis is a severe reaction in which no cause can be determined. It can affect individuals of all ages although females are affected much more frequently than males. Prophylactic daily treatment with a combination of medications can control the symptoms, and most episodes of idiopathic anaphylaxis subside spontaneously after several months or years.
Anyone with a previous history of anaphylactic reactions is at risk for another severe reaction. Individuals with food allergies (particularly shellfish, peanuts, and tree nuts) and asthma may be at increased risk for having a life-threatening anaphylactic reaction.
An anaphylactic reaction may begin with a tingling sensation, itching, or metallic taste in the mouth. Other symptoms can include hives, a sensation of warmth, asthma symptoms, swelling of the mouth and throat area, difficulty breathing, vomiting, diarrhea, cramping, a drop in blood pressure, and loss of consciousness. These symptoms may begin in as little as five to 15 minutes to up to two hours after exposure to the allergen, but life-threatening reactions may progress over hours.
Some individuals have a reaction, and the symptoms go away only to return two to three hours later. This is called a bi-phasic reaction. Often the symptoms occur in the respiratory tract and take the individual by surprise.
If you have an anaphylactic reaction, seek professional medical help quickly. Stay in the hospital for four to six hours to be sure you can get help if you have a bi-phasic reaction.
Epinephrine is the drug of choice for treating an anaphylactic reaction. It works to reverse the symptoms of an anaphylactic reaction and helps prevent the progression of it. It is available via prescription as and EpiPen® or EpiPen Jr. Epinephrine Auto-Injector. It is important to administer epinephrine as soon as one detects the symptoms of anaphylaxis.
Antihistamines and steroids are often used to further improve the recovery of a person with an anaphylactic reaction. Antihistamines and asthma medications may be administered with epinephrine, but never instead of epinephrine because they cannot reverse many of the symptoms of anaphylaxis.