Antibiotic Allergies in Pediatric Patients Diagnosed with Hypogammaglobulinemia

Rationale Hypogammaglobulinemia increases the risk of life-threatening bacterial infections that require antibiotic treatment in pediatric patients. Only a handful of studies have looked at the prevalence of allergies in patients with hypogammaglobulinemia. Even fewer have characterized antibiotic drug allergies in these patients. This study reports observed outcomes for patients at Lurie Children’s Hospital diagnosed with primary hypogammaglobulinemia and antibiotic allergy. Methods Using SlicerDicer built into Epic, pediatric patients were selected if they had a diagnosis of primary hypogammaglobulinemia, a low IgG level adjusted for age, and were seen between January 2015 and 2025 at Lurie Children’s Hospital. The charts of the patients with listed antibiotic allergies were analyzed. Results Our search yielded 243 patients with primary hypogammaglobulinemia, 46 (19%) of whom had an allergy to at least one antibiotic (31 male, 15 female). This was significantly higher than the prevalence of antibiotic allergies across all Lurie Children’s Hospital patients at 5% (p<<0.01). The most common antibiotic allergies were to amoxicillin (23), cephalosporins (15), and other penicillins (13). The most frequent reaction types were rashes (46%) and hives (35%) (see Figure 1). For patients with antibiotic allergies, the average age of hypogammaglobulinemia diagnosis was 7 years old. 12 (26%) of these patients had a diagnosis of recurrent infections. One patient had a documented drug challenge. Figure 1. Number of patients with an allergy to each antibiotic type, with a breakdown of the reaction types. There were 46 total patients with an antibiotic allergy, but some patients had an allergy to more than one drug type. Allergic reaction types did not differ significantly by drug. Within reaction types, GI sx refers to vomiting and/or diarrhea. Discussion Our findings suggest that pediatric hypogammaglobulinemia is associated with an increased frequency of antibiotic allergies, despite low levels of immunoglobulins. A potential explanation is that due to increased infections, patients with hypogammaglobulinemia have frequent exposure to antibiotics and develop adverse reactions. Further research is needed to elucidate the mechanisms behind these allergies in the setting of low immunoglobulins, considering drug allergies are thought to be IgE mediated. Many hypogammaglobulinemia patients will go through several courses of antibiotics throughout their lifetime. Having to revert to second- and third-line antibiotics can increase cost and medical burden for these patients and their families. Thus, antibiotic stewardship is especially important. Despite 46% of the drug allergic reactions being rashes, only one patient underwent a drug challenge, highlighting the need for more robust drug allergy evaluation.