Abstract
Urticaria is a common disease characterised by transient erythematous, oedematous, pruritic
wheals in the dermis due to the release of various inflammatory mediators from mast cells.
There was previously limited evidence on the effectiveness of hydroxychloroquine (HCQ) in
the literature but there is now emerging evidence that warrants further investigation. This
review aims to appraise the current literature and propose contemporary evidence
recommendations for hydroxychloroquine treatment of patients with urticaria by performing
a systematic review. The MEDLINE, Embase and Cochrane databases were searched from
inception to 12 June 2020 in accordance with the PRISMA guidelines. We also examined the
reference lists of the retrieved studies. Texts were reviewed independently by two authors.
The risk of bias and quality of the studies was assessed using the Critical Appraisal Skills
Programme for systematic reviews. A total of 7 studies were included, involving 211 pooled
trial participants. There was moderate-quality evidence from two RCTs that revealed the
effectiveness of HCQ in the subjective improvement of urticarial symptoms. Two case reports
and one case series also demonstrated the therapeutic benefit of HCQ for urticaria. There was
considerable heterogeneity of outcome variables and trial designs which did not permit a meta
analysis of the results. The limited available evidence reveals that HCQ is effective for the
resolution of urticaria. Further multi-centred, placebo-controlled, RCTs are required in order
to reveal the relative effectiveness of HCQ in comparison to current second-line treatment
modalities
Keywords
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