Chronic spontaneous urticaria—status quo and future

Chronic spontaneous urticaria (CsU) is a chronic inflammatory dermatosis whose etiology is not yet fully understood. In affected patients, it is often associated with a high limitation of health-related quality of life, which necessitates effective therapeutic management. Different immune cell populations such as mast cells, eosinophilic and basophilic granulocytes, and T cells are involved in the pathogenesis of CsU, whereby mast cells playing a key role. In addition, type I autoallergic reactions with auto IgE antibodies or type IIb autoimmune reactions with auto IgG antibodies have been identified in a proportion of patients. The current international guideline initially recommends the use of second-generation H1 antihistamines, first in standard, then in off-label quadruple dosing. Subsequently, the anti-IgE antibody omalizumab should be added. However, this therapy algorithm does not lead to freedom from manifestations in all patients. Therefore, various targeted therapies are currently being evaluated for their efficacy in CsU, such as off-label use of the anti-interleukin receptor alpha (IL4Rα) antibody dupilumab, the anti-IL-17A antibody secukinumab, or interleukin‑5 blockade using mepolizumab, reslizumab, or benralizumab. In addition, new promising compounds such as the Bruton tyrosine kinase (BTK) inhibitors remibrutinib and fenebrutinib, the anti-cKIT antibody barzolvolimab, the anti-SIGLEC8 antibody lirentelimab, the anti-TSLP antibody tezepelumab, the anti-C5aR1 antibody advoralimab, or the topical application of Syk kinase inhibitors are being tested, which were developed according to new insights into the pathogenesis of CsU. The BTK inhibitor fenebrutinib is currently not being pursued due to a less favorable side effect profile compared to remibrutinib, as well as the anti-IgE antibody ligelizumab, which was inferior to omalizumab therapy in a phase 3 study. Overall, there is a high need for new therapeutic strategies to better treat CsU both symptomatically and curatively. This requires a more comprehensive understanding of pathogenesis of the disease in order to develop new targeted therapies.