PA02 Dupilumab-induced eosinophilia in paediatric patients with eczema: pointers for dermatologists

Abstract Dupilumab has become a cornerstone therapy for moderate-to-severe atopic dermatitis (AD) in paediatric patients unresponsive to conventional systemic therapies. Additional approved indications include prurigo nodularis and severe asthma. However, an area that can be overlooked is dupilumab-induced hypereosinophilia. This is attributed to its inhibition of interleukin-4 and interleukin-13 signalling, which prevents eosinophil migration into tissues and raises circulating eosinophil levels. While this is typically transient, asymptomatic and independent of baseline eosinophil levels or treatment continuation, concerns remain regarding its potential to cause end-organ damage, including skin-related complications. Despite increasing reports, there are no standardized guidelines for dermatologists to monitor patients with AD receiving dupilumab, resulting in inconsistent clinical practices and a lack of evidence-based management strategies. To explore this issue, we conducted a retrospective analysis of 10 paediatric dermatology patients receiving dupilumab therapy for moderate-to-severe AD at a tertiary dermatology centre. The cohort comprised six female and four male patients (median age 12 years, range 6–18) with a median baseline Eczema Area and Severity Index (EASI) score of 25.5 (range 16.0–42.0) and a median Children’s Dermatology Life Quality Index (CDLQI) score of 18.5 (range 11.0–27.0). Median baseline eosinophil levels were 1.4 × 109 cells L−1 (range 0.6–2.7 × 109). Most patients had coexisting atopic conditions including food allergies (n = 9), hay fever (n = 3), dust mite allergies (n = 2) and severe asthma (n = 2). At the 16-week review, seven patients demonstrated significant clinical improvement, with median EASI scores reduced to 8.0 (range 3.9–11.0) and CDLQI scores to 3.0 (range 0–13.0), and no significant adverse effects reported. Two patients are pending their 16-week review but have shown interim improvements. One patient with baseline eosinophil levels of 3.0 × 109 cells L−1 and underlying asthma was referred to paediatric immunology for potential hyper-IgE syndrome but commenced dupilumab in the interim and is responding well to the therapy. Conversely, one patient with severe asthma experienced worsening skin flares, accompanied by proteinuria and a significant increase in eosinophil levels to 8.2 × 109 cells L−1 (from 2.7 × 109). Dupilumab was discontinued prior to their 16-week review, raising concerns regarding hypereosinophilic syndrome and potential end-organ damage. While severe eosinophilic complications in patients with AD treated with dupilumab are rare, cases of hypereosinophilic syndromes have been reported in individuals with underlying severe airway disease. This underscores the importance of proactive and vigilant monitoring of eosinophil levels, particularly in these high-risk patients. The majority of patients can be managed through their skin flares with topical treatments and oral corticosteroids if required. To address this need, we propose a standardized guideline for dermatologists to ensure safe and effective use of dupilumab in paediatric dermatology.