Extended Parasitic Screening in 1154 Adults with Chronic Spontaneous Urticaria: Diagnostic and Therapeutic Insights

Extended Parasitic Screening in 1154 Adults with Chronic Spontaneous Urticaria: Diagnostic and Therapeutic Insights | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 10 October 2025 V1 Latest version Share on Extended Parasitic Screening in 1154 Adults with Chronic Spontaneous Urticaria: Diagnostic and Therapeutic Insights Authors : Can Tuzer 0000-0002-8028-2647 [email protected] , Mark Ponsford 0000-0002-0236-1059 , Fethiye Akgul , Yusuf Arslan , Elif Okumus , Stephen Jolles , and Aslı Gelincik 0000-0002-3524-9952 Authors Info & Affiliations https://doi.org/10.22541/au.176012652.26191963/v1 434 views 191 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Background: Limited evidence suggests a link between occult parasites and chronic-spontaneous-urticaria (CSU). This study aimed to evaluate the diagnostic yield of indirect-hem-agglutination (IHA) tests and its clinical impact. Methods: CSU patients were screened for all parasites, including IHA tests for Echinococcus granulosus ( EG ) and Fasciola hepatica ( FH ). Subjects with positive IHA results (group A) were allocated according to the presence of EG (group A1) or FH (group A2). Eighteen controls (group B) from the remaining CSU subjects were randomly selected. Group A received anti-parasitic treatment additionally whereas group B, only CSU treatment. Basal urticaria-control-test (UCT), 7-day-Urticaria-Activity-Score (UAS7), Medication-Score (MS), Chronic-Urticaria-Quality-of-Life-Questionnaire (CU-Q2oL) and laboratory parameters were compared between groups and to follow-up values. Results: Seventeen (group A) out of 1154 patients were infected with EG (n:9, group A1) or FH (n:8 group A2) by IHA. Rural residency, CSU-remission, follow-up UCT and abdominal symptoms (p:0.049, p<0.001, p<0.001, p<0.001, respectively) and eosinophils and total-IgEs levels (p:0.02, p<0.001, respectively) were higher and follow-up UAS7, CU-Q2oL, MSs were lower in group A than in B (all p<0.001). At first-year follow-up, MS, UAS7, CU-Q2oL values decreased and UCT scores increased in group A (all p<0.001). Leukocytes, eosinophils and total IgEs in group A (p:0.011, p:0.047, p:0.001) and A2 (p:0.025, p:0.017, p:0.018), total-IgE in group A1 (p:0.036), and C-reactive-protein (CRP) in group A2 (p:0.025) declined. Conclusion: IHA testing for occult parasites may be considered particularly in CSU patients with abdominal symptoms, rural residency, eosinophilia, or elevated total IgE levels and anti-parasitic treatment can improve clinical outcomes. Extended Parasitic Screening in 1154 Adults with Chronic Spontaneous Urticaria: Diagnostic and Therapeutic Insights Can Tuzer 1,2 , Mark Ponsford 2 , Fethiye Akgul 3 , Yusuf Arslan 3 , Elif Okumus 4 , Stephen Jolles 2 , Aslı Gelincik 5 1 Immunology and Allergy Clinic, Batman Training and Research Hospital, Batman, Turkey 2 Immunology and Allergy Clinic, University hospital of Wales, Cardiff, UK 3 Infectious Diseases and Clinical Microbiology, Batman Training and Research Hospital, Batman, Turkey 4 Medical Microbiology Clinic, Batman Training and Research Hospital, Batman, Turkey 5 Immunology and Allergy Clinic, Istanbul Faculty of Medicine, Istanbul University Background: Limited evidence suggests a link between occult parasites and chronic-spontaneous-urticaria (CSU). This study aimed to evaluate the diagnostic yield of indirect-hem-agglutination (IHA) tests and its clinical impact. Methods: CSU patients were screened for all parasites, including IHA tests for Echinococcus granulosus ( EG ) and Fasciola hepatica ( FH ). Subjects with positive IHA results (group A) were allocated according to the presence of EG (group A1) or FH (group A2). Eighteen controls (group B) from the remaining CSU subjects were randomly selected. Group A received anti-parasitic treatment additionally whereas group B, only CSU treatment. Basal urticaria-control-test (UCT), 7-day-Urticaria-Activity-Score (UAS7), Medication-Score (MS), Chronic-Urticaria-Quality-of-Life-Questionnaire (CU-Q2oL) and laboratory parameters were compared between groups and to follow-up values. Results: Seventeen (group A) out of 1154 patients were infected with EG (n:9, group A1) or FH (n:8 group A2) by IHA. Rural residency, CSU-remission, follow-up UCT and abdominal symptoms (p:0.049, p<0.001, p<0.001, p<0.001, respectively) and eosinophils and total-IgEs levels (p:0.02, p<0.001, respectively) were higher and follow-up UAS7, CU-Q2oL, MSs were lower in group A than in B (all p<0.001). At first-year follow-up, MS, UAS7, CU-Q2oL values decreased and UCT scores increased in group A (all p<0.001). Leukocytes, eosinophils and total IgEs in group A (p:0.011, p:0.047, p:0.001) and A2 (p:0.025, p:0.017, p:0.018), total-IgE in group A1 (p:0.036), and C-reactive-protein (CRP) in group A2 (p:0.025) declined. Conclusion: IHA testing for occult parasites may be considered particularly in CSU patients with abdominal symptoms, rural residency, eosinophilia, or elevated total IgE levels and anti-parasitic treatment can improve clinical outcomes. Keyword: Chronic spontaneous urticaria, indirect hemagglutination test, parasitic infection, Echinococcus granulosus, Fasciola hepatica Running Title: Parasitic screening in Chronic Spontaneous Urticaria Abbreviations (ALP) alkaline-phosphatase, (BMI) Body-mass-index, (CRP) C-reactive-protein, (CSU) Chronic-spontaneous-urticaria, (CU) Chronic-Urticaria, (UAS7) 7-day-Urticaria-Activity-Score, (UCT) Urticaria-control-test, (CU-Q2oL) Chronic-Urticaria-Quality-of-Life-Questionnaire, (EG) Echinococcus granulosus, (FH) Fasciola hepatica, (ELISA) Enzyme-Linked-Immunosorbent-Assay, (ERCP) endoscopic-retrograde-cholangio-pancreatography, (FECT) formalin-ethylacetate-concentration-technique, (GGT) gamma-glutamyl-transferase, (IHA) Indirect-hem-agglutination, (IQR) interquartile-range, (MCA) Mast cell activation, (MS) Medication-scores, (NPV) negative-predictive-value, (PPV) positive predictive value, (NSRS) non-skin-related-symptoms, (PAIR) puncture-aspiration-injection-re-aspiration, (ROC) receiver-operator-characteristic-curve, (SD) standard-deviation, (Th2) T-helper-2, Introduction Chronic-urticaria (CU) is characterized by the development of transient wheals, angioedema or both lasting > 6 weeks, with lifetime and point prevalence rates of 1.4% and 0.7% [1-2]. In CU, urticarial attacks can occur spontaneously without a distinct physical trigger, which is defined as chronic-spontaneous-urticaria (CSU). Autoimmunity, systemic diseases, pseudo-allergic reactions to food and infections have been described as underlying causes in CSU [2-4]. Some viral, bacterial and parasitic infections have been related to the development of CSU so far [4-7] and several mechanisms were suggested to explain the pathogenicity of parasitic infections. Mast cell activation (MCA) by IgEs, IgGs or anaphylatoxins (e.g. C5a), coagulation activation, T-helper-2 (Th2) immune pathway stimulation by alarmins (e.g. IL-33, IL-25) and eosinophil recruitment can be outlined in the pathogenicity [5]. In CSU, non-skin-related-symptoms (NSRS) may suggest an underlying cause [8]. Hence, fever, malaise, joint pain and gastrointestinal symptoms should be considered as the signs of a differential diagnosis as well as an underlying systemic or infectious disease [8-9]. Additionally, gastric symptoms can be overshadowed by allergic manifestations in parasitic infections [9]. Anti-parasitic treatment may alleviate CSU symptoms in addition to NSRS like gastrointestinal symptoms in parasite infected patients [10]. Serological screening can help to detect hidden parasitic causes in the etiology of CSU [11]. Therefore, the etiology remains unclear in the absence of a detailed history and targeted downstream testing. Regarding NSRS, we aimed to search occult parasitic infections by indirect-hem-agglutination (IHA) test, and demonstrate the demographic, clinical and laboratory hints in CSU patients with occult parasites. Methods Participant selection The adult (≥ 18 years) patients registered as the diagnosis of ‘urticaria’ at the allergy outpatient clinics between April 2021 and November 2022, according to EAACI/GA²LEN/EuroGuiDerm/APAAACI guidelines [2, 12] were retrospectively screened. The subjects having systemic diseases (e.g. mastocytosis, myeloproliferative diseases), chronic inducible urticaria, acute urticaria, urticarial vasculitis, auto-inflammatory/auto-immune disorders (e.g. Schnitzler’s syndrome, Still’s disease, Crohn’s disease, rheumatoid arthritis), periodic fever syndromes (e.g. Familial Mediterranean Fever) and infectious diseases other than parasitic infections were excluded from the study. Those having incomplete data were excluded too. In the remaining CSU patients, parasites were searched by both stool screening and IHA tests, for Echinococcus granulosus ( EG ) and Fasciola hepatica ( FH ) in blood. The subjects found infected with EG or FH by IHA tests despite a negative stool screening formed group A. Group A was later allocated into groups A1 and A2 according to the presence of EG or FH , respectively. The control group (group B) was selected from those having negative results in both stool screening and IHA tests using a stratified randomization technique matched by gender, age, body-mass-index (BMI) and CSU disease activity [13]. The best-matched each control was selected randomly on the day of each patient’ visit. Two control subjects were enrolled along with one patient at the same day since both were quite similar and bias could have been if one had been enrolled. The diagram of recruiting study participants is illustrated in graphical abstract. The ethical approval (number:321, date:18.09.2022) was taken from the Ethics Committee of Batman Training and Research hospital. All study participants gave written informed consent. Parasitic and laboratory screening Stool analysis: One or more consecutive fresh stool samples were collected from the patients and transferred to the laboratory on the same day for analysis. After an initial direct microscopic examination (saline and Lugol wet mount preparations), formalin-ethylacetate-concentration-technique (FECT) was applied to improve the detection of parasites. Fecal material (~500 mg) was added to 10 ml normal saline and shaken well. It was later taken into a centrifuge tube and centrifuged for 5 min. The supernatant was discarded and 10 ml 10% formalin solution was added to the sediment. Ethyl-acetate (~4 ml) was also added and the mixed solution was centrifuged for 5 min again. Lastly, the precipitate in the centrifuged solution was re-suspended with 0.85% saline solution and a drop from the solution was put onto a glass slide and observed under a microscope [14]. Additionally, the adhesive tape perianal method was performed to search for Enterobius vermicularis eggs [15]. IHA tests (®Fumouze, France): Blood samples were centrifuged at 1,500×g for 10 minutes at 4°C to separate the sera. All serum samples were processed within 24 hours and stored at +4°C until testing. The principle of this assay is based on the agglutination of erythrocytes coated with specific parasite antigens by the corresponding antibodies present in patient serums. Serum samples were serially diluted and incubated with antigen-sensitized sheep red blood cells in micro titer plates. After incubation, wells were inspected macroscopically to check agglutination patterns. The highest serum dilution producing visible agglutination was recorded as the antibody titer. Positive and negative control sera were included in each assay to ensure reliability and validity [16]. Based on established cut-off values, IHA titers ≥1:320 for EG [17-18] and FH [19-20] were accepted as positive. The sensitivity/specificity of IHA testing for EG and FH were as 88% /98.4% [17] and 96.1%/96.6% [21], respectively. Laboratory analysis: Baseline leukocyte, neutrophil, basophil and eosinophil counts, tryptase, total IgE, C-reactive-protein (CRP), aspartate aminotransferase, alanine aminotransferase, creatinine, alkaline-phosphatase (ALP), gamma-glutamyl-transferase (GGT), thyroid-stimulating hormone levels were evaluated. Positive results for anti-thyroid peroxidase, anti-thyroglobulin and antinuclear antibody were also assessed. Outcome measures Seven-day-urticaria-activity-scores (UAS7), urticaria-control-tests (UCT) were measured to assess the disease activity in CSU, and UCT values less than 12 were defined as uncontrolled and 12 or above, controlled [2]. For the quality-of-life assessment, the Turkish version of the Chronic-Urticaria-Quality-of-Life-Questionnaire (CU-Q2oL) was used. It is a 23‑item questionnaire and the minimum score is ranked as 0 and maximum, 100 for the total scores of assessments [22]. Additionally, a schedule from a study [23] was modified to measure medication-scores (MS). It is in Table-S1. Baseline characteristics including age, gender, BMI, residency area, smoking status, CSU duration, UAS7, UCT, MS, CU-Q2oL, family history of CSU, allergic and non-allergic comorbidities, fever, musculoskeletal pain, malaise, gastrointestinal symptoms such as abdominal pain, nausea, vomiting, diarrhea, bloating and gas, presence of angioedema, history of anaphylactic episodes were all noted in study groups. Rural residency was defined as living in the countryside (outside the city center). Therapeutic modalities and follow-up Group A1 received albendazole treatment 10–15 mg/kg/day over 3-6 months and in necessity, a surgical intervention or a puncture-aspiration-injection-re-aspiration (PAIR) technique was applied in line with the guidelines. Albendazole was also commenced as a concomitant therapy 4 days prior to invasive procedures and continued for 3 months [24-25]. Group A2 was given triclabendazole treatment 10-12 mg/kg/day on two consecutive days and endoscopic-retrograde-cholangio-pancreatography (ERCP) was performed in cases with biliary tract obstruction [26-27]. IHA tests and imaging techniques (ultrasonography or magnetic resonance or computed tomography) were administered at first and every 3 months during the one-year follow-up. The complete response to therapy for EG was the disappearance or complete calcification of cysts at the end of one-year follow-up [28] and for FH , it was the absence of abscess, patchy hypo-dense area, portal or splenic vein dilatation, focal perihepatic hyperdensity, gallbladder wall thickening, extra/intrahepatic biliary tract dilatation, periportal/peridiaphragmatic lymphadenopathy, hepatic subcapsular hematoma and perihepatic or intraabdominal free fluid [29]. All groups were assessed at admission and 1 year later. At first visit, the demographic, clinical and laboratory features were compared between groups. The values of UCT, UAS7, MS, CU-Q2oL, CRP, total IgE, leukocytes, neutrophils, basophils and eosinophils were re-evaluated 1 year later in groups A, A1 and A2. However, in group B, only parameters assessing CSU disease activity (UCT, UAS7, CU-Q2oL, MS) were re-measured. The remission for CSU was considered as having no urticarial symptoms without any medication for at least 6 months [10]. The initial and follow-up values were compared in each group. The study protocol is given in graphical abstract. Statistical analyses Descriptive data was analyzed using percentages and mean ± standard-deviation (SD) or median/interquartile-range (IQR) depending on the distribution of the data. The Pearson χ2 or Fisher’s exact test for categorical variables and Mann-Whitney U or Student’s t-test for numeric variables were used to compare where appropriate. Wilcoxon signed ranks test and paired sample t-test were used to compare numeric dependent variables where appropriate. Mc Nemar test was used for categorical dependent variables. Kruskal-Wallis or one-way analysis of variance test with Bonferroni correction were used between multiple groups depending on the distribution of the data. Binary logistic regression analysis using covariates with a value of p < 0.05 in univariate analysis was performed to define the risk factors for the infection with either EG or FH . Cutoff values for eosinophils and total IgE levels were determined by receiver-operator-characteristic-curve (ROC) analysis. In all analyses, p < 0.05 was considered as a significant result. Social Sciences version 24.0 (SPSS Inc., Chicago, IL, USA) and GraphPad Prism version 8.4.3 soft-ware were used to analyze the data and generate the graphs. Results Prevalence of parasitic infections detected by FECT, perianal tape, and IHA methodologies Across the urticaria data registry (n:2008), 854 patients comprising those with acute urticaria (n:447), chronic inducible urticaria (n: 284), mastocytosis (n:2), essential thrombocythemia (n:1), urticarial vasculitis (n:2), Schnitzler’s syndrome (n:1), rheumatoid arthritis (n:2), adult-onset Still’s disease (n:1), Sjögren’s syndrome (n:1), Crohn’s disease (n:1), celiac disease (n:2), familial mediterranean fever (n:1), ankylosing spondylitis (n:1), hepatitis C (n:1), hepatitis B (n: 18) and subjects with missing laboratory or clinical data (n:89) were excluded from the study. In the remaining 1154 patients, screening methods identified parasitic infections in 15 (1.3%) out of 1154 patients by FECT, in 3 (0.3%) by perianal tape method and in 17 (1.5%) by IHA tests. Parasite detection rates were similar by between FECT and IHA tests (p>0.05). The parasites, with an overall prevalence of 3%, were as follows: Entamoeba spp (n:9), EG (n:9), FH (n:8), Giardia intestinalis (n:3), Dientamoeba fragilis (n:3), Enterobius vermicularis (n:3) (Table-1). Patient and laboratory characteristics associated with parasite detection by IHA To assess the impact of anti-parasitic treatment in CSU patients having parasitic infections, we created an age-, gender- and CSU severity-matched control group randomly selected from the 1119 CSU patients without parasitic infection. Demographic, clinical and laboratory baseline values, follow-up data and comparisons are summarized in Table-2. More than half were female in groups A (n:11, 64.7%) and B (n:12, 66.7%), and mean ages were 45.11±13.18 and 36.27±14.46, respectively. Overall rural residency rate was more common in group A relative to controls (41.2% vs 11.1%; p:0.049), and was strongly associated with FH detection (75%). Presence of EG was related to history of anaphylactic episodes (8 episodes in 3 patients), previously labelled as idiopathic anaphylaxis. No history of anaphylaxis was documented for CSU patients with FH or in the parasite negative control group. Abdominal symptoms were strongly associated with the parasitic detection by IHA relative to the control group (94.1% vs 11.1%; p < 0.001) including abdominal pain, nausea, vomiting, diarrhea, bloating and gas (Table-2). There was no significant difference in the prevalence of these symptoms between the cases with EG and FH . Malaise showed a strong link to the presence of FH when compared between three groups (n:7/8, 87.5%, p:0.037). Presence of an abdominal symptom was a significant risk factor for detection of EG or FH in the multivariate logistic regression analysis using significant baseline clinical and laboratory variables in the univariate analysis (p: 0.015, OR [CI] = 107.831 [2.498–4655.661]) (Table-3). Detection of parasite by IHA was strongly associated with peripheral blood eosinophilia (p:0.02) and high total IgE levels (p<0.001). The comparisons of eosinophil count and total IgE levels between three groups are illustrated in Fig.1. All the 8 cases with FH had eosinophil counts exceeding the laboratory-specified upper limit of normal (500 n/µl), with the highest value of 22.590 n/µl. Indeed, 6 cases with severe eosinophilia (>5.000 n/µl) had been referred for hematological investigation to exclude malignancy following negative stool screening prior to the results of IHA testing. Optimal cutoff value for eosinophils to predict a parasite by IHA was found as 205 n/µl with 52.9% sensitivity, 61.1% specificity, 56.25% positive predictive value (PPV) and 57.89% negative-predictive-value (NPV) (AUC: 0.730, 95% CI: 0.558-0.903, p:0.02). It was 133.6 IU/mL with 76.5 sensitivity, 76.5 specificity, 76.5% PPV and 77.9% NPV for total IgE (AUC: 0.855, 95% CI: 0.722-0.998, p<0.001) (Fig.2). Also, increased ALP, GGT and CRP levels were observed in group A2, suggestive of biliary inflammation, when compared between three groups (p:0.05, p:0.016, p:0.001, respectively). Anti-parasitic therapy and clinical follow-up Group A1 except one patient took the albendazole treatment for 3 months. Two patients had a surgery and one, a PAIR treatment modality in addition to albendazole treatment due to active enlarged more than 10 cm hydatid cysts in the liver. One of the subjects who had a surgery showed no decrease in IHA titer so the albendazole treatment duration was extended to 6 months and eventually, serological titer responded by an eight-fold decline. Group A2 all received the triclabendazole treatment for 2 days and one patient underwent ERCP due to a biliary tract obstruction and jaundice. Serological titers and imaging techniques in both groups were assessed every 3 months. A complete response regarding EG was successfully obtained in group A1 at the end of one-year follow-up. However, 2 (25%) patients in group A2 had residual hypo-dense lesions in the liver despite having a good clinical and laboratory response. Impact of anti-parasitic therapy on CSU activity After one-year follow-up, the CSU remission rate in group A was higher than matched controls (p<0.001) and it was similar between groups A1 and A2. At study entry, CSU severity was uncontrolled in all patients but at follow-up, it was under control in all parasite-associated cases (n:17, 100%) and in 12 (66.7%) out of 18 controls (p:0.019). Ongoing anti-IgE treatment was ceased in one patient (5.9%) in group A whereas it was started in 4 (22.2%) patients amongst control subjects. CU-Q2oL, UAS7 declined while UCT increased in all groups (Table-4). MS also improved in groups A, A1 and A2 (p<0.001, p:0.007, p:0.008, respectively) whereas it increased in group B (p:0.04) (Table-4). While alleviations in CSU symptoms and MSs were observed after anti-parasitic treatment in group A, an increase in MSs was noticed in the control group despite a decline in CSU disease severity (Fig.3A-D). Among laboratory markers, levels of leukocytes, eosinophils and total IgEs decreased in groups A (p:0.011, p:0.047, p:0.001) and A2 (p:0.025, p:0.017, p:0.018) (Table-4). Total IgE levels declined in group A1 (p:0.036) too. However, CRP levels declined in only group A2 (p:0.025). The alterations in laboratory values during the follow-up in groups A1 and A2 are illustrated in Fig.3(E-F). Discussion In this study, the significant role of IHA testing for EG and FH in a large CSU cohort of 1,154 adults was firstly demonstrated. A low parasitic infection prevalence (~1.5%) was detected by stool examination-based methods and use of parasitic IHA screening resulted in nearly 100% increase in diagnostic yield. The patients with parasites typically had greater total IgE and eosinophil levels. Moreover, rural residency and NSRS like malaise or abdominal symptoms including abdominal pain, vomiting, nausea, diarrhea, bloating and gas were suggestive of an occult parasite. Besides, anti-parasitic treatment helped to achieve better clinical outcomes in these patients. Identifying the etiology in CSU needs a very thorough and time-consuming investigation. Parasitic infections, autoimmunity, systemic diseases, food or drug triggers can be involved in the etiology [2, 30]. The prevalence of parasites varies from 0% [31] to 75.4% (32] in CSU studies [2]. We found a low prevalence (~1.5%) by conventional parasitic screening methods, and the use of IHA screening resulted in nearly 100% increase in diagnostic yield. Detection of EG and FH by IHA enabled targeted anti-parasitic therapy in an additional 17 CSU patients, associated with complete remission of urticarial symptoms in 82.4% by comparison control subjects required multiple therapies for CSU including anti-IgE in 22.2%. Diagnosis of EG is based on radiological and serological screening [25] despite a false positivity rate of 10% by IHA [33]. However, unless a surgical procedure is performed, the diagnosis cannot be confirmed [34]. To detect FH , stool-examination based methods cannot be sensitive enough, depending on the infection period [19] and serological positivity rates for FH seems controversial in CSU. Moreover, the confirmation of serological diagnosis in FH is quite difficult since it should be proven by invasive procedures (e.g. laparoscopy, ERCP) and/or presence of eggs in stool, duodenal, or bile specimens [27, 35]. While a study showed no serological positivity of FH in CSU patients [36], a rate of 14.5% was shown in another one [11]. In the preceding studies, Enzyme-Linked-Immunosorbent-Assay (ELISA) was used. Although IHA screening for either EG or FH have not been performed in CSU cohorts previously, in 817 patients with gastrointestinal complaints, IHA positivity rate for FH was found as 5.5% [19]. We showed a positivity rate of 0.6% for FH and 0.8% for EG by IHA method in 1154 adult CSU patients for the first time. Specific IgEs, Th2 cytokines, alarmins such as thymic stromal lymphopoietin (TSLP), interleukin-25 (IL-25) and IL-33, anaphylatoxins (C5a, C3a), mast cells eosinophilic inflammation, complement-fixing IgG1 and IgG3 antibodies can have key regulatory roles in the development of urticaria related to parasitic infections [5]. Moreover, some parasite antigens may cross-react with other environmental allergens and host antigens in the skin [37-38]. Another theory, Th2 immunity might combat parasites by enhanced allergic inflammation [39]. However, eosinophils do not seem activated unexpectedly despite overproduction of interleukin-5 (Il-5) in EG related allergy [40-41]. Likewise, in this study, eosinophil counts did not differ in CSU patients by the presence of EG . Specific IgEs against elongation factor-1 beta/delta on EG were higher in EG positive CSU patients compared to those without urticaria, ranking 25%-75% in all subjects with EG [41-42]. In another study about EG , total IgE levels were also higher [43]. On the other side, in FH related allergy, eosinophils and total IgEs are both common significant laboratory markers [20, 44-48]. Also, chronic inflammation causes depositions and mucosal thickening in the liver and biliary tract in FH infection. Therefore, inflammatory markers and hepatobiliary tract enzymes can be disrupted in FH infections [27, 49-50]. In this study, FH positive patients showed a predilection for an increment in CRP, ALP, GGT levels besides total IgEs and eosinophils. As well as picturing similar results comparatively to previous studies, we also offered cutoff values for eosinophils and total IgEs to predict occult parasites in CSU patients. Despite limited number of positive results, the relevant thresholds increase the likelihood of detection an occult parasite and improve the cost-effectivity to screen CSU patients by IHA method. Parasitic infection prevalence is becoming a communal problem in developed countries. In the USA, 42.9% of emigrants having eosinophilia took a positive result by parasitic screening and 52.4 % of them were asymptomatic at admission [51]. However, it seems not only common in emigrants but also in European residents [52]. In addition to provenance country, some typical features such as dietary habits, travel history and related symptoms are considerable [53]. Herein, the most distinguishing one seems the presence of abdominal symptoms including abdominal pain, gas, nausea and vomiting [25, 27, 48, 50]. However, in CSU patients with parasites, gastrointestinal symptoms can be absent [54] and hydatid cists occasionally settle in atypical localizations without an overt symptom [55]. Interestingly, urticaria can be the only presenting symptom of hydatid cist [56]. In these cases, residency area, travel history to endemic regions or laboratory markers can be suggestive. The present study participants were all local residents in Batman and had no travel history to other regions. However, the rural residency and presence of abdominal symptoms were significantly noteworthy. Besides, anaphylaxis history was related to the presence of EG , supporting the literature [41, 57]. This study has a few limitations. First, the absence of IHA tests for other tissue parasites may have missed additional unusual parasites. However, IHA testing for parasitic pathogens in CSU is firstly performed and this study may prompt the way of molecularly screening a panel of pathogens. Second, tracking changes in clinical and laboratory variables took a long term since the guidelines and expert advice for parasitic infections emphasize to assess the anti-parasitic treatment response at 3-6 months’ intervals [24, 58]. For this reason, high-step CSU treatments may have not commenced earlier. Third, bias might be possible in assessing NSRS by patients’ perspective but there is no objective method to evaluate NSRS. Forth, a higher number of positive IHA test results can increase the sensitivity and specificity of the cut-off values for eosinophils and total IgEs. However, we believe that the limited number of these patients reflects the real-life experience and multicenter studies containing larger cohorts are needed to establish the diagnostic yield of IHA tests in clinical practice of CSU. In summary, this study highlights the role of hidden parasites in CSU that stool examination-based methods might underestimate the real prevalence. IHA testing serves the opportunity to identify occult parasitic infections particularly in patients with urticarial and gastrointestinal symptoms concurrent with eosinophilia and high total IgE levels. Acknowledgements Dr Tuzer, Dr Ponsford, Dr Akgul, Dr Arslan, Dr Okumus, Dr Jolles and Dr Gelincik have nothing to disclose. Conflicts of Interest The authors have no conflicts of interest to declare. References : 1. J. Fricke, G. Ávila, T. Keller, et al., “Prevalence of chronic urticaria in children and adults across the globe: Systematic review with meta-analysis,” Allergy 75 (2020): 423-432. 2. T. Zuberbier, A.H. Abdul Latiff, M. Abuzakouk, et al., “The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria,” Allergy 77 (2022): 734-766. 3. L. He, W. Yi, X. Huang, H. Long and Q. Lu, “Chronic Urticaria: Advances in Understanding of the Disease and Clinical Management,” Clinical Reviews in Allergy & Immunology 61 (2021): 424-448. 4. B. Wedi, U. Raap, D. Wieczorek and A. Kapp, “Urticaria and infections,” Allergy, asthma, and clinical immunology : official journal of the Canadian Society of Allergy and Clinical Immunology 5 (2009): 10. 5. P. Kolkhir, G. Balakirski, H. F. Merk, O. Olisova and M. Maurer, “Chronic spontaneous urticaria and internal parasites–a systematic review,” Allergy 71 (2016): 308-322. 6. U. Ronellenfitsch, A. Bircher, C. Hatz and J. Blum, “Parasiten als Ursache von Urtikaria. Helminthen und Protozooen als Auslöser der Nesselsucht?” [Parasites as a cause of urticaria. Helminths and protozoa as triggers of hives?], Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und Verwandte Gebiete 58 (2007): 133-141. 7. C. Y. Chu and T. Zuberbier, “Urticaria and the gut,” Current Opinion in Allergy and Clinical Immunology 20 (2020): 381-385. 8. P. Pyatilova, Y. Hackler, F. Aulenbacher, et al., “Non-Skin Related Symptoms Are Common in Chronic Spontaneous Urticaria and Linked to Active and Uncontrolled Disease: Results From the Chronic Urticaria Registry,” The Journal of Allergy and Clinical Immunology. In Practice 12 (2024): 1890-1899.e3. 9. A. Daschner and C. Cuéllar, “The hidden sense of symptoms: Urticaria can be beneficial,” Medical Hypotheses 75, no. 6 (2010): 623-636. 10. E. Arik Yilmaz, B Karaatmaca, C. Sackesen, et al.,” Parasitic Infections in Children with Chronic Spontaneous Urticaria,” International Archives of Allergy and Immunology 171 (2016): 130-135. 11. M. Demirci, M. Yildirim, B. C. Aridogan, V. Baysal, M. Korkmaz, “Tissue parasites in patients with chronic urticaria,” The Journal of Dermatology 30 (2003): 777–781. 12. T. Zuberbier, W. Aberer, R. Asero, et al., “The EAACI/GA²LEN/EDF/WAO guideline for the definition, classification, diagnosis and management of urticaria,” Allergy 73 (2018): 1393-1414. 13. M. Kang, B. G. Ragan and J. H. Park, “Issues in outcomes research: an overview of randomization techniques for clinical trials,” Journal of Athletic Training 43 (2008): 215-221. 14. T. Brummaier, L. Archasuksan, D. Watthanakulpanich, et al., “Improved Detection of Intestinal Helminth Infections with a Formalin Ethyl-Acetate-Based Concentration Technique Compared to a Crude Formalin Concentration Technique,” Tropical Medicine and Infectious Disease 6 (2021): 51. 15. Y. Guo, M.-K. Lu, H.-Y. Dong, et al., “Rural Left-Behind Children are Seriously Afflicted with Intestinal Helminth Infections in Southern Sichuah, China,” The Journal of Parasitology 108 (2022): 53-56. 16. S. Erganis, F. Sarzhanov, A. l. Funda Doğruman and K. Cağlar, “Comparison of Methods in the Serologic Diagnosis of Cystic Echinococcosis,” Acta Parasitologica 69 (2024): 1122-1131. 17. H. R. van Doorn, H. Hofwegen, R. Koelewijn, et al., “Reliable serodiagnosis of imported cystic echinococcosis with a commercial indirect hemagglutination assay,” Diagnostic Microbiology and Infectious Disease 57 (2007): 409-412. 18. F. N. Eris, C. Akisu, U. Aksoy,. Evaluation of two ELISA and two indirect hemagglutination tests for serodiagnosis of pulmonary hydatid disease. The Korean Journal of Parasitology 47 (2009): 427–429. 19. Y. E. Beyhan, H. Yılmaz, “Seroprevalence of fascioliasis in the eastern region of Turkey: an eight-year investigation.” The Turkish Journal of Gastroenterology : the Official Journal of Turkish Society of Gastroenterology 31 (2020): 746–751. 20. G. İ. Bayhan, A. T. Özkan and Y. E. Beyhan, “The clinical characteristics of fascioliasis in pediatric patients,” Turk Pediatri Arsivi 55 (2020): 67-71. 21. P. Wattre, M. Capron, A. Capron, “Le diagnostic immunologique de la distomatose à Fasciola hepatica (à propos de 105 observations) [Immunological diagnosis of Fasciola hepatica distomatosis. (apropos of 105 cases)],” Lille medical : journal de la Faculte de medecine et de pharmacie de l’Universite de Lille 23 (1978): 292–296. 22. E. Kocatürk, K. Weller, P. Martus, et al., “Turkish version of the chronic urticaria quality of life questionnaire: cultural adaptation, assessment of reliability and validity,” Acta Dermato-Venereologica 92 (2012): 419–425. 23. G. Sussman, J. Hébert, C. Barron, et al., “Real-life experiences with omalizumab for the treatment of chronic urticaria,” Annals of Allergy, Asthma & Immunology : official publication of the American College of Allergy, Asthma, & Immunology 112 (2014): 170-174. 24. Unknown author, “Guidelines for treatment of cystic and alveolar echinococcosis in humans. WHO Informal Working Group on Echinococcosis,” Bulletin of the World Health Organization 74 (1996): 231-242. 25. P. Kern, A. Menezes da Silva and O. Akhan, et al., “The Echinococcosis: Diagnosis, Clinical Management and Burden of Disease.” Advances in Parasitology 96 (2017): 259-369. 26. R. López-Vélez, A. Domínguez-Castellano and C. Garrón, “Successful treatment of human fascioliasis with triclabendazole,” European Journal of Clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology 18 (1999): 525-526. 27. V. K. Boşnak, İ. Karaoğlan, H. H. Sahin, et al., “Evaluation of patients diagnosed with fascioliasis: A six-year experience at a university hospital in Turkey ,” Journal of Infection in Developing Countries 10 (2016): 389-394. 28. E. Cappello, B. Cacopardo, E. Caltabiano, et al., “Epidemiology and clinical features of cystic hydatidosis in Western Sicily: a ten-year review.” World Journal of Gastroenterology 19 (2013): 9351-9358. 29. C. Göya, S. Özkaçmaz, M. Özgökçe, E. Turko, İ. Dündar and F. Durmaz, “Radiological evaluation of response to treatment in hepatobiliary fascioliasis,” Gastroenterologia y Hepatologia 45 (2022): 507-514. 30. O. Jirapongsananuruk, S. Pongpreuksa, P. Sangacharoenkit, N. Visitsunthorn and P. Vichyanond, “Identification of the etiologies of chronic urticaria in children: a prospective study of 94 patients,” Pediatric Allergy and Immunology : official publication of the European Society of Pediatric Allergy and Immunology 21 (2010): 508-514. 31. G. Kilic, N. Guler, A. Suleyman and Z. Tamay, “Chronic urticaria and autoimmunity in children.” Pediatric Allergy and Immunology : official publication of the European Society of Pediatric Allergy and Immunology 21 (2010): 837-842. 32. A. Frezzolini, S. Cadoni and O. De Pità, “Usefulness of the CD63 basophil activation test in detecting Anisakis hypersensitivity in patients with chronic urticaria: diagnosis and follow-up,” Clinical and Experimental Dermatology 35 (2010): 765-770. 33. A. K. Chemtai, T. R. Bowry, Z. Ahmad, “Evaluation of five immunodiagnostic techniques in echinococcosis patients,” Bulletin of the World Health Organization 59 (1981): 767–772. 34. H. Zait, B. Hamrioui, “Human cystic echinococcosis: Serological diagnosis by indirect hemagglutination test, enzyme-linked immunosorbent assay, immunoelectrophoresis, and immunoblotting in surgically confirmed patients versus cases diagnosed by imaging techniques,” Medecine et Maladies Infectieuses 50 (2020): 676–683. 35. A. Cosme, E. Ojeda, G. Cilla, et al., “Fasciolasis hepatobiliar. Estudio de una serie de 37 pacientes [Fasciola hepatica. study of a series of 37 patients],” Gastroenterologia y Hepatologia 24, no. 8 (2001): 375–380. 36. T. Dal, M. Ciçek, D. Uçmak, et al., Seroprevalence of IgG anti- Toxocara canis antibodies and anti- Fasciola sp . antibodies in patients with urticaria. La Clinica Terapeutica 164 (2013): 315–317. 37. C. M. Fitzsimmons, F. H. Falcone and D. W. Dunne, “Helminth Allergens, Parasite-Specific IgE, and Its Protective Role in Human Immunity,” Frontiers in Immunology 5 (2014): 61. 38. R. Chandrashekar, K. C. Curtis and G. J. Weil, “Molecular characterization of a parasite antigen in sera from onchocerciasis patients that is immunologically cross-reactive with human keratin,” The Journal of Infectious Diseases 171 (1995): 1586-1592. 39. P. J. Cooper, “Interactions between helminth parasites and allergy,” Current Opinion in Allergy and Clinical Immunology 9 (2009): 29-37. 40. R. Riganò, E. Profumo, A. Teggi and A. Siracusano, “Production of IL-5 and IL-6 by peripheral blood mononuclear cells (PBMC) from patients with Echinococcus granulosus infection,” Clinical and Experimental Immunology 105 (1996): 456-459. 41. D. A. Vuitton, “Echinococcosis and allergy,” Clinical Reviews in Allergy & Immunology 26 (2004): 93-104. 42. E. Ortona, P. Margutti, S. Vaccari, et al., “Elongation factor 1 beta/delta ( β/δ ) of Echinococcus granulosus and allergic manifestations in human cystic echinococcosis,” Clinical and Experimental Immunology 125 (2001): 110-116. 43. J. Torcal, M. Navarro-Zorraquino, R. Lozano, et al., “Immune response and in vivo production of cytokines in patients with liver hydatidosis,” Clinical and Experimental Immunology 106 (1996): 317-322. 44. B. V. Ulger, M. Kapan, A. Boyuk, et al., “ Fasciola hepatica infection at a University Clinic in Turkey,” Journal of Infection in Developing Countries 8 (2014): 1451-1455. 45. I. N. Hakyemez, G. Aktaş, H. Savli, A. Küçükbayrak, S. Gürel and T. Taş, “A Fascioliasis Case: a not Rare Cause of Hypereosinophilia in Developing Countries, Present in Developed too,” Mediterranean Journal of Hematology and Infectious Diseases 4 (2012): e2012029. 46. M. K. Karahocagil, H. Akdeniz, M. Sunnetcioglu, et al., “A familial outbreak of fascioliasis in Eastern Anatolia: a report with review of literature,” Acta Tropica 118 (2011): 177-183. 47. L. Rinaldi, V. Folliero, L. Restivo, et al., “Atypical Presentation of a Rare Parasitic Infection with Fasciola hepatica : A Multidisciplinary Case Report,” The American Journal of Case Reports 21 (2020): e924704. 48. O. Preza, I. Klapa, A. Tsiakalos, D. D. Cokkinos and A. Chatziioannou, “Fascioliasis: A challenging differential diagnosis for radiologists,” Journal of Radiology Case Reports 13 (2019): 11-16. 49. M. B. Tanabe, M. A. Caravedo, A. Clinton White, Jr and M. M. Cabada, “An Update on the Pathogenesis of Fascioliasis: What Do We Know?,” Research and Reports in Tropical Medicine 15 (2024): 13-24. 50. M. Kaya, R. Beştaş and S. Cetin, “Clinical presentation and management of Fasciola hepatica infection: single-center experience,” World Journal of Gastroenterology 17 (2011): 4899-4904. 51. A. Ding, M. Osorio, M. Teferi, et al., “A Retrospective Longitudinal Study of Refugees with Eosinophilia at an Academic Center in the United States From 2015 to 2020,” Open Forum Infectious Diseases 11 (2024) ofae430. 52. A. Comelli, E. Oliva, F. Bernieri, et al., “Screening and Diagnosis Access for Neglected and Tropical Parasitic Diseases in Italy: A National Survey,” Tropical Medicine and Infectious Disease 10 (2025) 153. 53. P. L. Minciullo, A. Cascio and S. Gangemi, “Association between urticaria and nematode infections,” Allergy and Asthma Proceedings 39 (2018): 86-95. 54. A. Giacometti, O. Cirioni, L. Antonicelli, et al., “Prevalence of intestinal parasites among individuals with allergic skin diseases,” The Journal of Parasitology 89 (2003): 490-492. 55. A. S. Celik, H. Yosunkaya, A. Yayilkan Ozyilmaz, K. B. Memis and S. Aydin, “ Echinococcus granulosus in atypical localizations: Five case reports,” World Journal of Nephrology 14 (2025): 103027. 56. E. Kritikou-Pliota, E. Galanakis, A. Siamopoulou, P. D. Lapatsanis. An unusual cause of mild urticaria. The Lancet. Infectious Diseases 1 (2001): 20. 57. A. Gelincik, F. Ozşeker, S. Büyüköztürk, B. Colakoğlu, M. Dal and A. Alper, “Recurrent anaphylaxis due to non-ruptured hepatic hydatid cysts,” International Archives of Allergy and Immunology 143 (2007): 296-298. 58. Unknown author, “WHO guidelines for the treatment of patients with cystic echinococcosis,” Geneva: World Health Organization; 2025, ISBN: 978-92-4-011047-2. Figure legends. Fig.1: The comparisons of eosinophil counts and total IgE levels between patient groups Fig.2: The results of ROC curve analysis for eosinophil counts and total IgE levels in detection of occult parasitic infections by indirect-hem-agglutination tests Fig.3: The comparisons between baseline and follow-up parameters in patient groups Supplementary Material File (table.1.docx) Download 22.83 KB File (table.2.docx) Download 38.19 KB File (table.3.docx) Download 20.15 KB File (table.4.docx) Download 29.59 KB Information & Authors Information Version history V1 Version 1 10 October 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords ige parasites urticaria Authors Affiliations Can Tuzer 0000-0002-8028-2647 [email protected] Batman Egitim ve Arastirma Hastanesi View all articles by this author Mark Ponsford 0000-0002-0236-1059 University of South Wales - Cardiff Campus View all articles by this author Fethiye Akgul Batman Egitim ve Arastirma Hastanesi View all articles by this author Yusuf Arslan Batman Egitim ve Arastirma Hastanesi View all articles by this author Elif Okumus Batman Egitim ve Arastirma Hastanesi View all articles by this author Stephen Jolles University of South Wales - Cardiff Campus View all articles by this author Aslı Gelincik 0000-0002-3524-9952 Istanbul Universitesi Istanbul Tip Fakultesi View all articles by this author Metrics & Citations Metrics Article Usage 434 views 191 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Can Tuzer, Mark Ponsford, Fethiye Akgul, et al. Extended Parasitic Screening in 1154 Adults with Chronic Spontaneous Urticaria: Diagnostic and Therapeutic Insights. Authorea . 10 October 2025. DOI: https://doi.org/10.22541/au.176012652.26191963/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. Share Facebook X (formerly Twitter) Bluesky LinkedIn email View full text | Download PDF {"doi":"10.22541/au.176012652.26191963/v1","type":"Article"} Now Reading: Share Figures Tables Close figure viewer Back to article Figure title goes here Change zoom level Go to figure location within the article Download figure Toggle share panel Toggle share panel Share Toggle information panel Toggle information panel Go to previous graphic Go to next graphic Go to previous table Go to next table All figures All tables View all material View all material xrefBack.goTo xrefBack.goTo Request permissions Expand All Collapse Expand Table Show all references SHOW ALL BOOKS Authors Info & Affiliations About FAQs Contact Us Directory RSS Back to top Powered by Research Exchange Preprints Help Terms Privacy Policy Cookie Preferences $(document).ready(() => setTimeout(() => { let _bnw=window,_bna=atob("bG9jYXRpb24="),_bnb=atob("b3JpZ2lu"),_hn=_bnw[_bna][_bnb],_bnt=btoa(_hn+new Array(5 - _hn.length % 4).join(" ")); $.get("/resource/lodash?t="+_bnt); },4000)); (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'9feb9b42e8d70db4',t:'MTc3OTI4Mjg4OA=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();