Although intestinal parasites are a possible cause of skin disorders, there are few case reports concerning the role of Blastocystis hominis in urticaria. To clarify this association, we determined the frequency of B. hominis genetic subtype in urticarial patients by stool culture and polymerase chain reaction (PCR) and evaluated the clinical and parasitological recovery of urticarial patients after treatment with metronidazole. Of 54 urticarial patients (group I), 18 (33.3%) were diagnosed as acute urticaria (group IA) and 36 (66.7%) were diagnosed as chronic (group IB). Thirty-three (61.1%) out of 54 urticarial (group I) patients were Blastocystis positive by stool culture and PCR. Out of these 33 patients, 21 were symptomatic and 12 were asymptomatic. The amoeboid form was found in 20 (95.2%) out of 21 symptomatic Blastocystis urticarial patients assuring their pathogenic potential. Of 50 normal control group (group II), four (8%) Blastocystis isolates were found with no amoeboid form. B. hominis subtype 3 was the only detected genotype in both groups. Of 20 symptomatic Blastocystis urticarial patients, 12 (60%) patients recovered symptomatically and parasitologically after one course of metronidazole. Recovery reached 100% on repeating the treatment for a second course with disappearance of the amoeboid form. It was concluded that acute urticaria of unknown etiology and chronic idiopathic urticaria patients who are resistant to the ordinary regimen of urticaria treatment might be examined for infection with B. hominis, in order to prescribe the proper specific anti-protozoan treatment.

Blastocystis hominis is a common intestinal parasite, with a prevalence in developing countries of up to 50%. The aim of this study was to investigate the association of this parasite with urticaria by determining the genotypic isotypes in the Egyptian population. In total, 54 patients with urticaria and 50 controls were enrolled in the study. Stool samples were examined and assessed by PCR. The parasite was detected in a significantly higher number (P < 0.001) of the patient group than the control group. There was no significant difference between the patients with acute and those with chronic urticaria (P = 0.2). The amoeboid form was found in 60.6% of Blastocystis-positive patients with urticaria, but in none of the healthy controls. Subtype 3 was the only isolate found in both the patient and control groups. We recommend treatment for Blastocystis-positive patients with urticaria in developing countries. The prevalence is much lower (around 10%) in developed countries, where treatment should only be considered in the absence of other possible causes of urticaria.

SummaryHuman cystic hydatidosis (cystic echinococcosis) is a chronic zoonotic disease that results from infection with the dog tapeworm Echinococcus granulosus. In Egypt, cystic echinococcosis (CE) is recognized in slaughtered livestock by veterinarians, however, there is little information about human CE infection rates. We describe an immunological assay useful for the diagnosis of human cystic hydatidosis. Sera were collected from surgically confirmed hydatid cases (34), nonendemic subjects free from parasitic infection (20) and from subjects (109) infected with other helminths (Hymenolepis nana, Schistosoma mansoni, Fasciola hepatica and Ancylostoma duodenale). Hydatid cyst fluid (HCF) of camel origin was used as antigen in an ELISA format to measure total E. granulosus specific IgG antibodies and IgG subclasses. Sensitivity measurements of total IgG, and IgG1-4 were 100, 100, 79.4, 61.8 and 55.9%, respectively, whereas respective specificity reached 65.1, 97.7, 98.4, 96.1 and 83.7%. The diagnostic value of measuring IgG1 (97.7%), as assessed by a rating index (J) for combined sensitivity and specificity, was superior to total IgG (65.1%) and IgG2-4 (77.8, 57.9 and 39.6%, respectively). These findings set the stage for field evaluation of the IgG1 assay in areas endemic with human cystic hydatidosis.