Laboratory tests
Complete blood count was available for 202 patients (80.8%) at the initial diagnosis of CSU. Eosinophilia (defined as eosinophil count > 500 cells/µL) was found in 29 patients (14.4%, range 500-1800 cells/µL) and was more common in children < 13 years (27.6% vs. 6.2% p< 0.01). Eosinophilia did not correlate with CSU duration or the presence of atopic diseases.
Total IgE was available for 60 patients (24%). High total IgE (defined as IgE > 100 IU), was found in 32 (53.3%). No correlation was found between high total IgE and atopic diseases or duration of urticaria.
C-reactive protein was measured in 109 patients at CSU presentation and was within the normal range in all cases. Antinuclear antibody was measured in 51 patients and found abnormal in 6 (11.8%). Of them, in the following years, one patient was diagnosed with hyperthyroidism, 1 with hypothyroidism and IBS, and 1 with Alport’s syndrome.