Characterization of Contact Urticaria Syndrome Phenotypes: A Retrospective Study of 95 Cases

Contact urticaria syndrome, encompassing immunological contact urticaria and protein contact dermatitis, comprises immediate cutaneous reactions with potential systemic manifestations, including anaphylaxis. These conditions are frequently underdiagnosed despite their significant occupational impact. This study aimed to evaluate the clinical and laboratory features associated with distinct phenotypes of contact urticaria syndrome. A retrospective, observational analysis was performed at Hospital del Mar (Barcelona) from January 2010 to January 2024, including adult patients diagnosed with immunological contact urticaria and/or protein contact dermatitis and a positive prick test. Demographic data, clinical data, and complementary test results, including culprit agents, were compared between patients with isolated contact urticaria and those with protein contact dermatitis. A total of 95 patients were included. Results indicated that isolated contact urticaria was more frequently associated with facial involvement (n = 19, 28.8%) and a higher rate of systemic reactions (n = 18, 27.3%), including anaphylaxis, whereas protein contact dermatitis was frequently occupational-related (n = 19, 65.5%), and with a trend toward higher atopic dermatitis comorbidity (n = 12, 41.4%). These findings emphasize the heterogeneity of contact urticaria syndrome and underscore the importance of comprehensive clinical evaluation for effective diagnosis and management.