Chronic urticaria phenotypes: clinical differences regarding triggers, activity, prognosis and therapeutic response.

Background: The subtypes of chronic urticaria (CU) share a common clinical expression, but phenotypically may show differences.
Objectives: To evaluate sociodemographic and clinical differences in CU phenotypes, including: (1) isolated chronic spontaneous urticaria (CSU); (2) isolated chronic inducible urticaria (CIndU); (3) CSU with concomitant CIndU (CSU-CIndU); (4) CSU with single or multiple episodes; (5) early and late-onset CSU (<45/65 years vs ≥45/65 years); and (6) CSU with presence vs absence of serum autoreactivity.
Materials and Methods: A retrospective observational study of 997 patients with urticaria was performed, with clinical, laboratory and therapeutic comparisons between CU subtypes.
Results: A clear female predominance was detected for CU, mostly in patients with serum autoreactivity. CIndU patients were younger, showed less angioedema, and had a better response to antihistamines. Stress and drugs were the main triggering factors for CSU. Patients with exclusive CIndU or recurrent CSU showed less psychiatric comorbidities. Patients with concomitant CIndU and serum autoreactivity showed greater urticaria activity.
Conclusion: Knowledge of the clinical differences between CSU subtypes may help to define an individual therapeutic strategy and improve the control of symptoms and quality of life.