Chronic Urticaria and Malignancy: A Review Uncovering the Common Links

Background: Chronic urticaria (CU) is a complex skin condition, frequently challenging both patients and clinicians and requiring wise individualized management. While allergy, autoimmunity, and depression are recognized comorbidities, evidence linking CU and malignancy remains underexplored. Screening for malignancy is not a routine standard of care for CU patients. Methods: A literature review was conducted to explore the potential risk or associations, including immune mechanisms, between CU and malignancy, based on searches in the PubMed and Google Scholar databases. Results: Scientific evidence on the malignancy risk in CU and its causal relationship is limited to a few population-based studies and case reports. A higher incidence of hematologic malignancy in CU patients has been reported in several publications, but the overall risk of malignancy in the CU population remains controversial. Antihistamine resistance, ultra-low IgE, and older age at the time of CU diagnosis may be related to a higher risk of malignancy, especially shortly after CU diagnosis. Immunological pathways linking CU and cancer are not clear. Immune system dysregulation, including alterations in immune checkpoints, is a feature of both cancer and CU. Such dysregulation may promote immunotolerance, abnormal immune responses, and mast cell activation through novel autoantigens and autoantibodies involved in the tumor microenvironment. Conclusions: There is growing, although limited, evidence suggesting a possible link between CU and malignancy, especially hematologic cancers. Large multicenter cohort studies are warranted to determine whether CU may act as a clinical harbinger of malignancy and to identify patient subsets that may benefit from targeted cancer screening.