Successful oral desensitization for systemic peanut allergy.

To the Editor: The present strategy of avoidance and epinephrine autoinjection for severe IgE-mediated food reactions is not always successful.1,2 This may be even truer for young children, who cannot read and have to depend on adults to administer the epinephrine. The following case report illustrates such a failure in a young child and describes a treatment that can be performed by an allergy specialist as an alternative to the avoidance-and-epinephrine strategy. The patient is a 6-year-old girl who had 2 systemic reactions to peanuts as a preschooler. The mother and child practiced avoidance measures. The mother provided an epinephrine autoinjector and instructions to the school nurse. While at school, another student was eating a peanut butter sandwich at the patient’s table. The child was touched by the other child. She denied eating any part of the sandwich. She complained to the teacher of shortness of breath, rash, and itching. The teacher tried to contact the school nurse; however, the nurse was not readily available. By the time the nurse came to administer the epinephrine, the child had collapsed. The emergency medical technician arrived and gave the child additional epinephrine. They started an intravenous infusion and transferred the child to the hospital. After an extended observation and treatment period, she was discharged. The parents were extremely distraught by the events, since they had done all they had been advised to do. There was a real risk of continuing emotional duress for the parents and the child. The child’s mother, who was so worried that she was considering quitting her job and keeping the child at home, asked if there were any alternatives. A review of the literature suggested that oral desensitization might offer a way to protect the child against unintentional exposures or ingestion.3–9 The process and procedure were explained to the parents. They were told that the goal was to ensure that the child would not have a reaction to unintentional modest exposures, not to make her eat peanuts as a normal food. They agreed and signed an informed consent form. The oral challenge and desensitization were performed with crushed peanuts in grape juice concentrate. The staff and equipment to treat an anaphylactic reaction were in place, including intravenous solutions and airways and pediatric manual resuscitators with oxygen. A staff member with extensive experience in intubation of children was available. Because of these unusual requirements, the procedure was performed in our office. The office is also one block from a fully equipped hospital emergency department. During the procedure, the child’s pulse rate, blood pressure, and oxygen saturation were monitored. Two placebo doses were given first. Doubling of peanut concentrations from 250 g to 8 g (4 whole kernels) every 15 minutes was planned. However, this goal was not achieved initially. After ingesting one peanut kernel, the child developed a small amount of rash and mild wheezing. Her blood pressure did not change. The wheezing was treated with a bronchodilator. The rash disappeared within 15 minutes, and she did not require epinephrine or antihistamines. The child’s mother was instructed to give a half kernel 3 times daily to the child. The first such dose was given 6 hours later in clinic. During an 8-week period, this amount of peanut was gradually increased in the clinic until the child tolerated 2 whole peanuts (4 whole kernels) 3 times daily. Subsequently, this was changed to ingesting 2 whole peanuts twice daily. She has been receiving this treatment for more than a year. There has been one contact with a schoolmate eating a peanut butter sandwich without a reaction. She has eaten a granola bar that was later shown to contain peanut flour without reaction. This clinical tolerance has been accompanied by immunologic changes. Her peanut specific IgE level was more than 100 IU at baseline, 74 IU at 6 months, and 42 IU at 12 months. Oral desensitization is a well-established procedure for severe IgE-mediated reactions to drugs, commonly performed by allergy specialists. Most often this is done correctly in an intensive care unit or similar facility. The staff skills and equipment in our office are not required for most allergy practices. We strongly suggest that the oral desensitization procedure only be done where complete ability to treat anaphylaxis exists. We intend to continue daily peanut therapy in this child and monitor levels of specific IgE and IgG for 24 to 36 months. At that time we plan to evaluate whether this therapy needs to be continued. Our experience concerns severe peanut allergy and may not be generalizable to all IgE-mediated food reactions. Oral desensitization for IgE-mediated food allergy has been previously reported.3–9 Currently, oral food desensitization may be useful in patients such as this one, for whom the situation had become dysfunctional. The procedure needs to be performed carefully in an adequate facility and with full understanding by the parents of what the goals and limitations of the treatment are. Although other approaches are being evaluated for severe food allergic reactions, such as sublingual food immunotherapy and monoclonal anti-IgE, further study of oral desensitization for food allergy in selected situations seems worthwhile given the magnitude of this vexing clinical problem and the need for better treatments.