Community Private Practice Clinical Experience with Peanut Oral Immunotherapy.

Background: Peanut oral immunotherapy is an effective treatment for desensitizing peanut-allergic patients, but the frequency of adverse reactions has limited its widespread use.

Objective: To review the frequency of adverse reactions that patients on peanut oral immunotherapy experience during build-up and maintenance phases and explore factors that may contribute to adverse events.

Methods: A retrospective chart review of children and adults with peanut allergy undergoing peanut oral immunotherapy at the New England Food Allergy Treatment Center in West Hartford, Conn was performed. Data on patient demographics, allergic profile, peanut allergy testing, and details of reactions in build-up and maintenance phases were collected. A systemic reaction was defined as one of the following: (1) severe reaction involving 1 system, such as generalized hives and/or angioedema; (2) 2 or more of the following symptoms: cutaneous or oral, respiratory, or gastrointestinal symptoms; (3) drop in blood pressure; or (4) need for epinephrine.

Results: Data were available on 783 patients aged 3.5 to 48.3 years. During buildup, 78 patients (10%) experienced at least 1 systemic reaction, 660 (84%) at least 1 gastrointestinal adverse event, 369 (47%) at least 1 cutaneous adverse event, and 157 (20%) at least 1 respiratory adverse event. Thirty-four patients (4%) required epinephrine during buildup. Six hundred ninety-seven patients (89%) completed buildup and progressed to maintenance. During maintenance, 131 patients (19%) experienced at least 1 systemic reaction, 190 (27%) at least 1 gastrointestinal adverse event, 104 (15%) at least 1 cutaneous adverse event, and 50 (7%) at least 1 respiratory adverse event. Seventy-four patients (11%) required epinephrine during maintenance. None of the adverse events required hospitalizations, and there were no mortalities. Nine patients (1%) were diagnosed with eosinophilic esophagitis during buildup or maintenance. Increasing pretreatment peanut specific IgE levels were associated with increased odds of a systemic reaction during buildup. Increasing age, pretreatment peanut specific IgE level, and a systemic reaction in buildup were associated with increased odds of a systemic reaction during maintenance.

Conclusions: Peanut oral immunotherapy may be an effective and safe treatment for carefully selected peanut-allergic patients under the guidance of experienced providers. Specific patient characteristics and immunologic factors may help predict adverse events.