Yacoub MR, et al. - In patients with chronic spontaneous urticaria (CSU) incompletely controlled by first-line antihistamine therapy, researchers tested the validity of a hypothesis that a 30-day oral supplementation with diamine oxidase (DAO) (1 capsule b.i.d., 15 min before a meal) could reduce the severity of CSU as estimated by the 7-Day Urticaria Activity Score (UAS-7). Relative to placebo, a 3.8 ± 1.2 point mean ± SEM UAS-7 score reduction was noted in patients with low serum DAO levels at time 0, as a consequence of receiving supplemental therapy with DAO. Overall, a possible implication of DAO in the pathogenic cascade of CSU was suggested, along with possible efficacy of DAO supplementation for symptom relief in patients with low DAO levels in serum.