Anaphylaxis and Food Allergy: Diagnosis and Treatment

Diagnosis

• A medical history and physical examination are the most important steps.
• Skin or blood testing can be used to identify allergenic foods. In addition, a placebo–controlled food challenge can be used. In this test, which is done under medical supervision, the patient eats a small amount of the food allergen, as well as a placebo, to establish whether a food allergy really exists.

Treatment

• Immediate medical attention may be required. Hospitalization and possibly intubation may be necessary for severe cases.
  
• The inciting agent should be removed, if possible. A tourniquet above the site of a venom sting or site of an allergy shot injection may be helpful.
• An epinephrine shot can be used for mild to moderate symptoms. Epinephrine should be administered as soon as the diagnosis of anaphylaxis is considered. It may be self–administered with an EpiPen or similar device and can be repeated at 15–minute intervals en route to an emergency department.
• Antihistamine medications (e.g., diphenhydramine (Benadryl), loratadine (Claritin), and ranitidine (Zantac)) should be used until anaphylaxis resolves. In addition, intravenous steroids are usually used in moderate and severe cases.
  
• Asthma inhalers may be used if wheezing occurs.
• If the patient has low blood pressure, immediate administration of intravenous fluids and various medications (e.g., dopamine, norepinephrine, phenylephrine, and vasopressin) may be life–saving.
• Patients with more than mild symptoms should be observed in the emergency department or admitted to the hospital for continued observation.