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

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.