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 describe what they are comparing against? Yes Are data sources clear and is the primary outcome operationally defined? Yes Is the timeline clear? Yes Do they measure whether the intervention was actually delivered/used as intended? Yes  Do they include patient health outcomes? No  Do they describe organizational barriers/facilitators that affect readiness? Yes Do they report who/what was eligible vs who/what actually participated? Yes Do they describe the maintenance and sustainability of their interventions over time? Yes Do they address whether the intervention could be replicated elsewhere? Yes Do they discuss limitations? Yes Funding of the Study. No funding for this study. No declared conflicts of interest. Results: The study included 1235 pediatric ED patients and 737 inpatients. They undertook a total of 5 PDSA cycles, including the ED and inpatient units. Key Results: FGA use decreased and cetirizine use increased after implementation of QI initiatives. The use of FGA decreased from 74% to 28% in the pediatric ED and 54% to 36% in the inpatient units. The use of cetirizine went from 31% to 75% in the pediatric ED and 54% to 74% un the inpatient units. The changes were sustained for 8.5 months in the pediatric ED and 9 months in the inpatient units. Secondary Outcomes Knowledge assessment improved (among 31 surveyed participants): Median 50% to 100%. Clinical pathway usage increased: Median 36 to 44 clinicians/month. Balancing measures: ED revisit within 48 hours and median inpatient LOS remained stable. Cost: Monthly median antihistamine costs increased (PED $53 to $177; inpatient $57 to $104), with discussion of unit cost drivers for cetirizine formulation. A crucial part of any QI process is the identification of key stakeholders. This study included representation from the pediatric ED, a pediatric resident (a great inclusion given that residents rotate through so many units in the hospital), allergy and immunology, and pharmacy. These stakeholders helped the group identify the key drivers that included education and awareness, availability of cetirizine, and standardization of preferred medication. Individuals from each group of stakeholders also acted as champions to help push the QI initiative. Uncontrolled Before-After Design QI studies do not necessarily need to include control groups. However, without a concurrent control group/unit, improvements can reflect background practice drift, staffing changes, guideline diffusion, seasonal case-mix shifts, or other QI initiatives rather than the intervention itself. are a classic threat in time-based comparisons. In addition, when clinicians are aware a practice is being measured (or receive peer-to-peer feedback), behavior can shift independent of the intrinsic effectiveness of the intervention. This is well described as the Hawthorne effect and the related sentinel effect [3]. Intervention Bundle Because they implemented multiple components (education, stocking, reminders, pathway updates, audit/feedback), the observed effect can’t be confidently attributed to any single change. This is a common challenge with complex interventions, where fidelity and mechanism can vary across units and time.  Education and Awareness Reliance on purely educational interventions for QI will likely only have a limited effect. For this study, the authors did a 30-minute lecture during a staff meeting and emailed the lecture materials to absent staff. They also put up flyers in work areas. This intervention in the first PDSA cycle did not result in a consistent reduction in first-generation antihistamine use. Based on feedback from a PDSA flyer, they also shortened the educational sessions for the inpatient implementation phase, recognizing that attention wanes after 15-20 minutes. Cetirizine Availability The group worked with the pharmacy in the hospital to ensure the cetirizine solution and tablets were available in the medication dispensing machines. They emailed the pediatric ED staff to let them know. It is important to recognize that some children may either be too young or unable to swallow tablets or pills. This seems like a basic step, but if we want people to start using something new or different, we should try to make it accessible to them. Standardizing Preferred Antihistamines Now that the alternative second-generation antihistamine is available, there’s another step this group took to help with adopting the change. They looked at the existing clinical pathways for anaphylaxis and penicillin allergy delabeling and changed the primary antihistamine recommendation from diphenhydramine to cetirizine. This is a nice way of making it easy for people to adopt the change. For those already accustomed to using the clinical pathway and order set, this does not really change workflow at all. Indications for Antihistamines