Authors’ conclusions
The very limited evidence provided by this review was based on a few old studies of a relatively small size, which we categorised as
having high to unclear risk of bias. Thus, at present, the review does not allow confident decision-making about the use of H2-receptor
antagonists for urticaria. Although some of these studies have reported a measure of relief of symptoms of urticaria and rather minimal
clinical improvement in some of the participants, the evidence was weak and unreliable. We have emphasised the lack of precision and
limitations in the reported data where appropriate in this review.