SGEM#506: Aww I’m Itchy…and I need a Second Generation Antihistamine

Reference: Wong KH, et al. Improving Use of Oral Antihistamines in a Children’s Hospital. Pediatrics. Feb 2026; Date: March 15, 2026 Dr. Stephanie Kubala Guest Skeptic: Dr. Stephanie Kubala is an attending physician in the Division of Allergy and Immunology at Children’s Hospital of Philadelphia. She is double board-certified in both pediatrics and allergy and immunology. Case: A 5-year-old girl is brought in by her parents for an itchy rash. Her symptoms started last night. The parent reports an itchy, raised red rash on her trunk and extremities. She has not had any fever. She does not have any difficulty breathing, wheezing, vomiting, or diarrhea. On your exam, you note hives on her body but no lip or tongue swelling. Her lungs are clear to auscultation. She intermittently scratches at the rash. Her parents tell you, “We gave her a dose of diphenhydramine last night, and it may have helped a little, but it seems to have worn off. Can you help?” Background: In a lot of emergency departments, “hives = diphenhydramine” is practically muscle memory. It’s familiar, it’s been around forever, and families often expect it because it’s what they already have at home. As with many medical interventions, we must weigh potential harms against potential benefits. The problem is that diphenhydramine and other first-generation antihistamines like hydroxyzine come with a bunch of potential side effects, such as sedation, anticholinergic side effects, and unpredictable behavior changes in some kids. It doesn’t always last very long, which can lead to repeat dosing and frustrated families when symptoms come back a few hours later. On the other hand, second-generation antihistamines like cetirizine target the same H1 receptor for itch and urticaria but tend to be longer-acting and better tolerated, which is why many guidelines and expert groups prefer them for routine allergic symptoms. And there’s a bigger safety angle here, too: first-generation agents show up in dosing errors and misuse/overdose cases. The real issue isn’t whether second-generation antihistamines like cetirizine work. They do. We need to start asking why our systems still nudge clinicians toward the older first-generation antihistamines as a default. The issue is well-suited to a quality improvement (QI) study. Before we dive into the details of the study itself, let’s talk about some basics around QI. QI helps close the gap between best practice and day-to-day care. It starts with a clear, measurable aim (what you want to improve, by how much, by when). This is followed by a simple measurement plan: an outcome measure (the main result you’re trying to change), process measures (the steps that should drive that result), and balancing measures (what might worsen unintentionally). Teams then map the current workflow, identify barriers, and build a key driver diagram that links the aim to the handful of system levers most likely to move the needle. The work is tested and refined using Plan–Do–Study–Act (PDSA) cycles. [2] These are iterative rather than a single big rollout. Data is tracked over time with run/control charts to show whether changes are real and sustained. Clinical Question: Can a bundled QI approach meaningfully reduce first generation antihistamine use and increase cetirizine use among pediatric patients receiving oral antihistamines in the ED and inpatient settings? Reference: Wong KH, et al. Improving Use of Oral Antihistamines in a Children’s Hospital. Pediatrics. Feb 2026; Population: Patients 6 months to 21 years in the pediatric ED and inpatient units at a tertiary academic children’s hospital Excluded: Patients in NICU, PICU, or hematology-oncology units Intervention: There were 3 main drivers: education/awareness, cetirizine availability, and standardization through clinical pathways. Comparison: Pre-intervention baseline prescribing practices Outcome: Primary Outcomes: There are two primary outcomes: The proportion receiving oral FGA and the proportion receiving cetirizine Secondary Outcomes: PED revisits within 48 hours, median LOS, clinicians’ knowledge, frequency of clinical pathway use and monthly antihistamine cost. Type of Study: Quality improvement initiative Authors’ Conclusions: “Using the Model for Improvement, we reduced FGA use and increased cetirizine use in the PED and inpatient setting.” Quality Checklist for Ql Study (adapted from QI-MQCS): Do they clearly state the problem and why it mattered? Yes Do they explain why the intervention should improve the outcome? Yes Are the specific changes described in enough detail that another site could reproduce them? Unsure  Do they describe the setting the intervention took place (type of hospital/clinic, size, population)? Yes  Do they describe the approach to designing and introducing the program? Yes Is the evaluation approach explicit? Yes Do they d