Histamine release positive test associates with disease remission in chronic spontaneous urticaria: a proof-of-concept study

Background. Histamine release (HR) test has previously been shown to predict the presence of endogenous histamine releasing factors in chronic spontaneous urticaria (CSU). Objectives-Methods. Twenty CSU patients unresponsive to antihistamine treatment were enrolled, in order to evaluate the correlations between HR test results and demographic features, quality of life, disease activity, clinical course and both in vivo autologous serum and plasma skin tests (ASST and APST). Results. All patients with positive HR test (9/9, 100%) had a more severe disease ac-tivity at onset (urticaria activity score, UAS > 2) when compared to negative HR test patients (5/11; p = 0.04). Quality of life questionnaires' results were not substantially different between HR positive and negative subgroups at baseline (p > 0.05), and results of HR test and ASST/APST did not cosegregate (p > 0.05). After 12 months, patients with a positive HR test had a significant reduction of disease activity (p = 0.003), whereas patients with a negative HR test did not (p > 0.05), leading to disease remission and antihistamine treatment withdrawal in 67% (6/9) of pos-itive HR test patients versus 18% (2/11) of negative HR test patients (p = 0.027). Conclusions. Positive HR test may predict spontaneous CSU remission at 12 months.