IgE‐mediated allergy: a rare cause of chronic spontaneous urticarial with allergen‐specific immunotherapy as treatment option – a systematic review with meta‐analysis from China

Background  Allergen-specific immunotherapy (SIT) has long been a controversial treatment for chronic urticaria (CU), although SIT has been used in patients with allergic diseases for more than 90 years. Objectives  To evaluate the efficacy and safety of SIT vs. conventional treatment (CT) in the treatment of CU. Methods  Systematic searches were conducted without language restrictions in MEDLINE, EMBASE, the Cochrane Library, ISI Web of Knowledge, China National Knowledge Infrastructure, and Chinese Scientific Journals Full Text Database. The primary outcomes were efficacy and quality of life (QOL) and the secondary outcomes were relapse rate and adverse events (AEs). Results  Fourteen studies (1838 patients) were included. None of them was double-blind placebo controlled. Our study demonstrated that SIT seemed to show more clinical efficacy rate (OR 2.39; 95% CI, 1.73–3.30; I2 = 55%, P = 0.008), more complete recovery rate (OR 2.13; 95% CI, 1.55–2.91; I2 = 61%, P=0.008) and less relapse rate 2 weeks after treatment (OR 0.38; 95% CI, 0.24–0.61; I2 = 36%, P=0.20) than CT. Only one study reported improved QOL and no study reported serious AEs after SIT. Conclusions  Current evidence indicates that IgE-mediated allergy may be causative in a small number of CU patients and specific immunotherapy with these allergens may be beneficial in those patients. However, the number of included studies was small and those qualities were low. So, available evidence is not adequate to draw an affirmative conclusion and larger studies of high quality are needed to provide increasingly convincing data and cases.