Anaphylaxis Due to Food
Anaphylaxis is dangerous. Up to 1000 people die each year in the US due to anaphylaxis. Foods are the most common cause. 30% of the time the trigger is a food allergy, and 90% of the time it is due to peanut or tree nut exposure. These reactions are difficult to predict since the severity of an allergic reaction to food cannot be predicted by history or by skin prick or allergen-specific IGE level testing. 25% of the time the first episode of anaphylaxis has not been preceded by any prior food reaction.
The most common symptoms are skin, respiratory, gastrointestinal, and cardiovascular symptoms. Skin symptoms include hives, itching, flushing of the skin and swelling of the lips, tongue or uvula. Respiratory symptoms include shortness of breath, wheezing, stridor or a low oxygen level in the blood. Gastrointestinal symptoms include crampy abdominal pain and vomiting. Cardiovascular symptoms include fainting, collapse, low blood pressure and urinary incontinence.
Injection of epinephrine into the thigh is the best treatment. The dose is .15 mg for persons less than 55 pounds and .3 mg for those weighing more. Having two doses available is important since 20% of the time a second dose is required. Many people do not know that in 20% of the cases there is a biphasic pattern to symptoms with symptoms returning after initial treatment success. Other treatments include placing the child supine on the ground with legs elevated or in a position of comfort. Oxygen and intravenous fluid therapy may be needed. Antihistamine treatment with a medication like Benadryl only treats skin symptoms and has no cardiovascular benefits.
Management of food-induced anaphylaxis at school is very important. School staff must be aware of food-allergic children and an emergency action plan for treatment must be in place. Medication must be available and staff must be trained to administer the medication and notify emergency personnel. Safe food practices must be maintained with only designated foods being available and surface and hand washing before and after meals. No food sharing is allowed. Prevention strategies are age and maturity dependent. In the US children with a diagnosis of anaphylaxis are protected by the American with Disabilities Act that prevents discrimination based on disability. Children with food allergies are often bullied due to issues with social isolation brought on by food limitations.
The majority of people who have a severe episode of anaphylaxis also have asthma. Exercise and alcohol also increase the severity of anaphylaxis.
