Giardiasis is a protozoal infection that typically presents with diarrhea, abdominal pain, and malabsorption. Peripheral eosinophilia is unusual and may confound diagnosis by suggesting eosinophilic gastrointestinal disease (EGID). We present a 41-year-old woman with abdominal pain, diarrhea, malabsorption, and peripheral eosinophilia. Endoscopic biopsy performed shortly after anti-parasitic therapy demonstrated eosinophilic duodenitis, raising concern for eosinophilic gastroenteritis. However, repeat biopsy after recovery revealed resolution of eosinophilia, excluding EGID. This case highlights the importance of timing diagnostic endoscopy after giardiasis treatment to avoid misdiagnosis.

Amyopathic dermatomyositis (ADM) is a rare variant of dermatomyositis characterised by the pathognomonic cutaneous features of the disease in the absence of clinically significant muscle weakness for at least 6 months. Peripheral eosinophilia is an uncommon laboratory finding associated with ADM and is more commonly linked to allergic, parasitic or haematological disorders.We present the case of a woman in her 70s with classic cutaneous signs of dermatomyositis associated with pruritus for 3 years, preserved muscle strength and persistent peripheral eosinophilia. Secondary causes of eosinophilia were excluded, and a diagnosis of ADM was made based on clinical features and antibody positivity. The patient showed an adequate response to systemic corticosteroids, with resolution of skin lesions and normalisation of eosinophil counts.This case highlights the importance of considering ADM in patients presenting with unexplained eosinophilia and characteristic cutaneous manifestations and adds to the limited literature describing eosinophilic manifestations in inflammatory myopathies.

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare Anti-neutrophil cytoplasm antibodies (ANCA)-associated vasculitis with multi-organ involvement and eosinophilia. We present a 61-year-old male with a history of eosinophilic asthma who developed progressive weakness and muscle aches six weeks after his second COVID-19 booster. Four to six weeks post vaccination, he developed myal gias and weakness, especially in proximal muscles, leading to a severe decline in function. Lab results showed leukocytosis (29.54 cells/mm³); 54% eosinophils; and elevated erythrocyte sedimentation rate (ESR), C-reactive protein, and creatine kinase levels at 13 736 u/L. Anti-myeloperoxidase antibodies were positive, while PR-3, C-ANCA, and P-ANCA were negative. Magnetic resonance imaging of the lower extremities showed intramuscular edema. Muscle biopsies confirmed EGPA. Diagnosed per American College of Rheumatology (ACR)/ European Alliance of Associations for Rheumatology (EULAR) criteria, he received pulse dose IV methylprednisolone with significant improvement. He was discharged on 60 mg prednisone and started on mepolizumab (300 mg subcutaneous once every 4 weeks). Eosinophilic granulomatosis with polyangiitis progresses through stages: asthma, eosinophilia with organ involvement, and vasculitis. This case highlights a unique presentation of rapid myositis without significant involvement of any other organs and vasculitis post-mRNA vaccination. While environmental factors may trigger EGPA, the role of COVID-19 vaccines remains hypothesis-generating. This case underscores the importance of post-market surveillance for rare events, contributing to the understanding of vaccine-related rheumatic disease triggers Cite this article as: Memdani A, Busa V, Avula S, Ford A, Nesheiwat J. Unmasking Eosinophilic granulomatosis with polyangiitis: a case of rapid-onset myositis following COVID-19 booster in an eosinophilic asthma patient. Eur J Rheumatol. 2025, 13(1), 0016, doi:10.5152/eurjrheum.2026.25016.

Purpose: To report a rare case of Vogt-Koyanagi-Harada disease (VKH)-like uveitis following drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome associated with human herpesvirus 6 viremia. Methods: A single case was reviewed. Results: A 34-year-old man presented with bilateral blurred vision and photophobia 3 months after an episode of DRESS secondary to antipsychotic medications. Ocular examination revealed bilateral anterior chamber and vitreous inflammation, serous macular retinal detachments, optic disc edema, and bacillary detachment in the left eye. Diagnostic testing was negative for infectious and inflammatory causes but demonstrated eosinophilia. A diagnosis of VKH-like disease secondary to DRESS was made. Systemic corticosteroid and steroid-sparing therapies were initiated, resulting in complete resolution of symptoms and clinical findings over 8 months. Conclusions: VKH-like disease may rarely be triggered by DRESS syndrome, although this association has not been previously reported in the ophthalmic literature. Further research is necessary to understand the relationship between these entities and the role of human herpesvirus 6 in their pathogenesis.

Our study aimed to evaluate the therapeutic potential of a 20% ethanolic extract of the Phlomis umbrosa Turcz. (EPT) herb and its associated bioactive compounds in an ovalbumin (OVA)-induced allergic asthma mouse model. We used phytochemical analysis and identified sesamoside, shanzhiside methyl ester, 8-O-acetyl shanzhiside methyl ester, and isoacteoside as the bioactive components. We validated and quantitatively analyzed shanzhiside methyl ester as a major compound. The treatment with EPT significantly attenuated the T helper type 2 (Th2)-based immune response, eosinophilia, histopathological changes, and biochemical parameters. Furthermore, EPT inhibited interleukin (IL)-33-mediated activation of the nuclear factor kappa B (NF-κB) and transforming growth factor beta (TGF-β) signaling pathways, as well as reduced fibrosis and apoptosis associated with inflammation. The findings of our study suggest that EPT is a promising natural substance for alleviating symptoms of allergic asthma.

The incidence of inflammatory bowel disease (IBD) and metabolic syndrome (MetS) has risen in recent years, but the relationship between the 2 remains understudied. This retrospective cohort study aimed to explore the impact of MetS on disease activity in IBD. Retrospective analysis of 676 consecutive IBD patients treated from January 2023 to April 2024. Study participants were stratified into a control cohort of 531 patients with uncomplicated IBD, and an exposure cohort of 145 patients with IBD and concurrent MetS. Data were collected and analyzed for all 676 patients at baseline and after 1-year follow-up. From an initial pool of 1730 potentially eligible patients, 156 (9%) were identified with MetS (IBD-MetS cohort: 86% ulcerative colitis and 14% Crohn's disease). Baseline clinical disease activity was significantly higher than in the IBD-only controls, with concomitant elevations in biomarkers including monocytosis, eosinophilia, elevated C-reactive protein and elevated erythrocyte sedimentation rate. At 12-months' follow-up, the IBD-MetS group showed significantly lower rates of clinical remission (54.48% vs 82.49%) and mucosal healing (24.83% vs 41.05%) compared to the controls. Inflammatory biomarkers remained elevated, consistent with baseline findings. After propensity score-matched analysis, a comparative analysis of 145 matched controls and 145 exposed groups showed that, compared to IBD-only patients, IBD-MetS patients still had significantly lower rates of clinical remission (54.48% vs 77.93%, odds ratio: 0.339, 95% confidence interval: 0.203-0.565, P < .001) and mucosal healing (24.83% vs 41.38%, odds ratio: 0.468, 95% confidence interval: 0.283-0.772, P = .003). Our findings indicate that MetS is correlated with increased disease activity in IBD. These findings emphasize the need for clinicians to identify and intervene in metabolic syndrome components in IBD patients, ultimately improving quality of life and providing new insights for future IBD-MetS research.

Eosinophilic myocarditis can result from drug hypersensitivity or various systemic disorders. Although corticosteroids are effective, treatment strategies are not standardized.

Interleukin-5 (IL-5) is central to eosinophil differentiation, survival, and activation. Subsequent studies confirmed IL-5 receptor expression and mapped downstream signaling, showing that IL-5 promotes not only survival but also trafficking and effector functions, including adhesion, degranulation, reactive oxygen species generation, mediator release (cytokines and cysteinyl leukotrienes), and extracellular trap formation. However, the roles of eosinophils vary across diseases and tissue compartments. Multi-omics analyses of blood and tissue eosinophils across transcriptomic, proteomic, and lipid-metabolic layers reveal disease- and site-specific molecular states. These data support two opposing classes of modulators that shape IL-5-driven programs: pro-inflammatory signals (IL-4/IL-13, IL-33, NOD2-mediated innate signaling, and IFN-γ) that drive inflammatory eosinophil changes and can cooperate in some settings, and counter-regulatory signals (IFN-α and all-trans retinoic acid [ATRA]) that restrain these changes. Such modulation may influence tissue retention, effector functions, and broader eosinophil activities, including antiviral and homeostatic roles. Clinical studies of anti-IL-5 and/or anti-IL-5Rα biologics in severe eosinophilic asthma, chronic rhinosinusitis with nasal polyps, eosinophilic granulomatosis with polyangiitis, hypereosinophilic syndromes, and other eosinophilic diseases have improved outcomes, underscoring that disease activity often depends on IL-5-driven eosinophil activation despite disease-specific IL-5-independent signals. In this review, we summarize IL-5 biology from mechanisms to therapy and discuss how integrated multi-omics signatures and clinical biomarkers may guide patient stratification, therapy selection, and treatment sequencing toward precision medicine for eosinophilic respiratory and systemic diseases. .

Löffler's syndrome is classically described as a transient pulmonary disorder associated with eosinophilic infiltration of the lungs, most commonly triggered by helminthic larval migration. While eosinophilia is considered a defining feature, rare cases lacking peripheral or pulmonary eosinophilia have been reported, complicating recognition and diagnosis. Disseminated helminthic infection with multiorgan involvement is an additional uncommon manifestation that may further obscure clinical identification. We describe a case of a 40-year-old woman with extensive environmental and animal exposure who developed pulmonary, neurologic, gastrointestinal, and cutaneous symptoms following suspected household zoonotic helminthic transmission. Despite elevated immunoglobulin E (IgE) levels and characteristic clinical features suggestive of larval migration, peripheral eosinophilia was absent. Multiple household members developed similar symptoms, supporting a shared exposure. The patient improved following empiric antihelminthic therapy and coordinated treatment of household contacts and domestic animals. This case highlights a rare non-eosinophilic variant of a Löffler-like pulmonary syndrome associated with disseminated helminthic infection and underscores the importance of considering parasitic disease in patients with multisystem symptoms and environmental exposure, even in the absence of eosinophilia.

Severe cutaneous adverse reactions are a spectrum of life-threatening immune mediated adverse drug reactions characterized by extensive skin involvement with the potential for organ injury. It is composed of four main entities: drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, toxic epidermal necrolysis, and acute generalized exanthematous pustulosis. With prominent hypereosinophilia (>1500 eosinophils/µL), hypereosinophilic syndrome also warrants consideration, albeit rarely triggered by medications. In addition, there may also be concern for infectious etiologies, particularly in patients with notable travel history or immunosuppression. Herein, we present the case of a 65-year-old man with multiple myeloma who was started on several medications simultaneously for the induction of chemotherapy and who developed a full-body pruritic and maculopapular rash and peripheral eosinophilia 2-to-4 weeks after initiation of these medications. He had a recalcitrant course, which required multiple rounds of systemic steroids and other treatments. After a detailed history, physical examination, and additional investigation coupled with high clinical suspicion, a diagnosis, and treatment plan was made.

Background: Eosinophilic esophagitis (EoE) is a chronic inflammatory and an immune-mediated condition diagnosed based on both clinical and pathologic findings. EoE has been identified as one of the leading causes of esophageal dysfunction worldwide. If untreated, EoE often follows a progressive course that leads to fibrosis and esophageal stricture and perforation. The use of biologic therapies that target specific pathways will help us understand the essential pathophysiologic steps in EoE, in addition to providing symptomatic treatment. In this narrative review, we review the potential targeted therapies of these cells and related pathways, the evidence of therapeutic benefit, and suggestions for future therapeutic approaches. An updated review of treatment options is necessary given deeper understanding of the pathogenesis and more recent advances in treatment since the consensus recommendations published in 2016. Objective: We sought to review the contemporary data with regard to treatment approaches in EoE, particularly through immune-modulating therapeutic approaches. Methods: The MEDLINE (PubMed) data base was queried by using specified search terms. Articles were selected based on their contribution to the understanding of how therapeutics for EoE, particularly those that modulate immunity play a role in the management of this disease. Results: Among immune-modulating therapies for EoE, anti-interleukin (IL) 5/IL-5 Receptor (R) α and anti-IL-13/IL-4 Receptor (R) α therapies have the most accumulated clinical trial and safety data at this time. Other emerging immunologic targets that warrant discussion include thymic stromal lymphopoietin and Sialic acid-binding IG-like lectin 8 (Siglec-8). Furthermore, the contribution of fibroblasts and myofibroblasts to the pathogenesis of EoE also provides many potential therapeutic targets. Allergen-specific immunotherapies have shown variable benefit in the treatment of EoE. Conclusion: Immune-modulating therapies seem to be a promising avenue of the treatment of EoE; both established and emerging targets of therapy exist to manage this condition.