Drug Allergies in Immunodeficiencies: a Single-Center Experience in Southern California

About 10% of individuals in the US report penicillin allergy. However, after a complete evaluation, more than 90% of these patients can tolerate penicillin. The label of penicillin allergy has negative health implications including the use of broad spectrum antibiotics, increased healthcare costs, high risk of treatment failure, infectious complications and antimicrobial resistance. Patients with immunodeficiencies develop recurrent and severe infections necessitating frequent use of antibiotics. Data on reported and physician-confirmed drug allergy in patients with immunodeficiency is limited. A retrospective review of electronic medical records was performed of patients seen in immunology clinic between January 1, 2018 and January 1, 2022. Data collected included demographics, listed drug allergies (along with the documented reaction), comorbidities, immunologic evaluation, current treatments, and past allergy evaluation of drug allergies and confirmed drug allergy diagnosis. The mean age was 58 years. There were 327 women and 144 men. The most common immunodeficiency diagnoses were specific antibody deficiency (36.1%), hypogammaglobulinemia (29.9%), common variable immunodeficiency (29.7%), and IgG subclass deficiency (25.9%). Seventy three percent had at least one reported drug allergy and 24.3% had reported penicillin allergy. The most common reported antibiotic allergy was sulfa antibiotics at 30.3%. Mucocutaneous (27%) followed by gastrointestinal (4.6%) symptoms were the most reported penicillin allergy reactions. There was no association between reported penicillin allergy and type of immunodeficiency, serum IgE, IgG, IgA, or IgM levels. Female gender, presence of autoimmunity, and IVIG treatment were associated with reported penicillin allergy. The diagnosis of penicillin allergy was confirmed in only 1 of 19 patients referred for an allergy evaluation. In this study, we observed a higher incidence of penicillin allergy in adult patients with immunodeficiencies than in the general population. The most prevalent antibiotic allergy in this group was sulfa antibiotic allergy. Formal allergy evaluation was conducted on a small subset of patients and showed that the incidence of true penicillin allergy is much lower than reported. This study highlights the importance of an active approach to penicillin allergy de-labeling.