Both Extrinsic and Intrinsic Atopy in Chronic Spontaneous Urticaria Patients Indicate a Favorable Response to Omalizumab Treatment.

Background

Chronic spontaneous urticaria (CSU), a debilitating condition, is often treated with omalizumab for antihistamine-refractory cases. Atopy subtypes (extrinsic/intrinsic) may influence CSU clinical features and treatment responses, but remain understudied.

Objective

To assess the clinical relevance of atopy subtypes in CSU and their link to omalizumab response.

Methods

Retrospective analysis of 210 omalizumab-treated CSU patients assessed through allergen-specific immunoglobulin E (IgE), total IgE, personal/family history, and atopic signs. Groups: nonatopic, extrinsic, or intrinsic atopic. Treatment response, onset speed, and safety profiles were evaluated.

Results

Atopy prevalence was 70% (extrinsic: 50.5%, intrinsic: 19.5%). Extrinsic atopic patients showed higher personal/family urticaria history and annular/semi-annular wheals. Nonatopic patients were older, with more red plaques/patches and higher IgG-anti-thyroid microsome (IgG-anti-TM) positivity. Atopy predicted a favorable omalizumab response. Omalizumab response rates were superior in extrinsic (97.2%) and intrinsic (95.1%) groups versus nonatopic (77.8%, P < 0.001). Nonatopic patients experienced faster symptom relief (28.6% ≤24 hours vs 9.7-20.5%, P = 0.012). Adverse events were more frequent in atopic subgroups (18.9-22.0% vs 4.8%, P = 0.020). Low total IgE (<40 IU/mL) correlated with reduced group responses.

Conclusion

Both extrinsic and intrinsic atopy predict better omalizumab responses in CSU. Intrinsic atopic CSU, often neglected, requires further study for personalized approaches. Comprehensive atopy evaluation improves therapeutic stratification in CSU.