Chronic spontaneous urticaria (CSU) may be associated with intestinal parasites and Helicobacter pylori (H. pylori) infection, the objective of this study was to detect intestinal parasites and Helicobacter pylori coproantigen in 40 patients complaining of urticaria for unknown reasons for more than 6 weeks as cases in comparison with 40 healthy controls. Intestinal parasites were detected in 17/40 (42.5%) and 6/40 (15%) cases and controls, respectively. Blastocystis hominis was found 14/40 (35%), and 6/40 (15%) in cases and controls, respectively which was statistical significance (p=0.039). Cryptosporidium spp. was found in 4/40 (10%) and Entamoeba spp. 2/40 (5%) in cases which were statistically non-significance.
             Helicobacter pylori coproantigen was found in 24/40 (60%) cases and 14/40 (35%) in controls showing a significant association (P=0.025). The Restriction Fragment Length Polymorphism (REFLP) identified Blastocystis spp. in the cases after nested PCR of SSU rDNA sequences with the predominance of ST3. The 2 cases of Entamoeba were differentiated using multiplex PCR and found that one case was Entamoeba dispar and the other one was Entamoeba histolytica. Out of 40 cases, 52% reported gastrointestinal symptoms as; upper abdominal pain 25%, diarrhea 27.5% and other manifestations were reported as; fever 25% and headache 32.5%.  Among the H. pylori-positive samples; 12/24 (50%) were co-infected with intestinal parasites; Blastocystis spp. 9/24 (37.5/%), Cryptosporidium spp. 3/24 (12.5%) and Entamoeba dispar 1/24 (4.2%). Non-significant differences were noticed among cases in terms of H. Pylori positivity regarding age, sex and clinical manifestation.