Fig. 1

Attack frequency in relation to antihistamine prophylaxis. Attack frequencies were evaluated at maximum antihistamine dose prescribed (prior to add-on therapy) a box-and-whiskers-plot of attack frequency at first visit (V1) and follow-up (FU) with (+),or without intervention (−), bold line = median, Mann–Whitney and Wilcoxon test were used comparing groups respectively paired samples. b Percentage of patients reporting improvement per maximum dose antihistamines prescribed, improvement was defined as shift into a lower attack frequency group, n = total patients per group, patients with missing data on attack frequency could not be evaluated for improvement (n = 25). c Attack frequency per maximum dose prescribed