The following is the summary of “Most Patients With Autoimmune Chronic Spontaneous Urticaria Also Have Autoallergic Urticaria, but Not Vice Versa,” published in the February 2023 issue of Allergy and Clinical Immunology by Yi-Kui Xiang, et al.

Scientists have identified two different types of chronic spontaneous urticaria (CSU) that are linked to mast cell-activating autoantibodies: autoimmune chronic spontaneous urticaria (aiCSU) and autoallergic chronic spontaneous urticaria (aaCSU). The former is associated with IgG anti-high-affinity receptor for the Fc region of immunoglobulin E (FcεRI)/IgE, while the latter is associated with immunoglobulin E (IgE) anti-autoallergens. Researchers conducted a study to determine the prevalence of two CSU endotypes: aaCSU and aiCSU. The study included 111 CSU patients and their IgE levels were analyzed to thyroid peroxidase and interleukin 24 for aaCSU, and for aiCSU. The study also compared clinical and laboratory parameters in patients with either aaCSU, aiCSU, or both.

The study examined 111 patients with CSU and found that 58% of them had autoallergic CSU (aaCSU), and 8% had autoimmune CSU (aiCSU). Of the patients with aiCSU, 8 out of 9 also had aaCSU, while only 8 out of 64 patients with aaCSU had aiCSU. Overall, 7% of patients had both aiCSU and aaCSU, 41% had neither, and 16% tested negative for all markers of aiCSU and aaCSU assessed. The study also found that patients with aaCSU or aiCSU tend to differ from those without. Patients with stand-alone aaCSU are typically younger, while patients with aiCSU, with or without aaCSU, are more often female and experience more severe quality of life impairment. The authors suggest that their findings regarding aiCSU coexisting with aaCSU should be confirmed in larger, multicenter studies and that further research is needed to better understand the pathophysiology of autoimmunity driven by autoreactive IgE and/or IgG in CSU.