Consultation with the Specialist: Who Needs Allergy Testing and How to Get It Done

Abstract

1. Robert C. Cartwright, MD* 2. William K. Dolen, MD* 1. *Allergy-Immunology Section, Departments of Pediatrics and Medicine, Medical College of Georgia, Augusta, Ga After completing this article, readers should be able to: 1. Understand the indications for immunoglobulin E allergy testing in patients who have allergic disorders. 2. Discuss advantages and disadvantages of different allergy tests. 3. Recognize factors that can influence allergy test results. ### Patient 1 A 15-year-old girl whom you have been following since birth is rushed to the local emergency department (ED) following dinner at the family’s favorite restaurant. During the meal, she developed facial flushing, acute urticaria, vomiting, and diarrhea. In the ED, she is given epinephrine and diphenhydramine, and the symptoms resolve. At a follow-up visit the next day in your office, the girl’s mother informs you that her daughter had eaten cashew-crusted tuna with a serving of fresh fruit, including mango, papaya, and kiwi. ### Patient 2 A 4-year-old boy is playing outside and is stung by an unidentified insect. He runs inside crying, and his mother cleans the sting site on his hand. Over the next 2 hours, the hand and distal forearm become red, swollen, and pruritic. His mother takes him to a local ED. He is given diphenhydramine and parenteral corticosteroids and is observed for several hours. Several days later, the ED calls the mother to report that a honeybee venom allergy test performed in the ED is positive at a level of 2.3 kU/L. Immunologic reactions traditionally are classified by using the Gell and Coombs system (Table1). This simple scheme is useful for learning and thinking about different mechanisms of immunopathology, although a medical condition in an individual patient might involve more than one of the mechanisms. Reactions involving immunoglobulin (Ig)E-mediated immediate hypersensitivity are called type I. Cytotoxic reactions that are Ig-mediated are called type II. Mechanisms involving immune complexes are type III, and type IV reactions are delayed hypersensitivity reactions mediated by T cells. Antigen-specific tests are available clinically …