How to assess disease activity in patients with chronic urticaria?

Background: The current EAACI/GA(2)LEN/EDF guidelines recommend assessing disease activity in chronic urticaria (CU) by using an established and well-defined symptom score, i.e. the urticaria activity score (UAS), which combines daily wheal numbers and pruritus intensity. However, this UAS has never been formally tested for its suitability in assessing CU activity. Aim: To determine the UAS correlation with quality of life (QoL) in CU patients and to compare the UAS to other symptom scores. Methods: Chronic urticaria symptoms (wheals, erythema, angioedema, pruritus) were assessed on seven consecutive days in 111 CU patients for their numbers, duration, size, and/or intensity. Quality of life was assessed by using the Dermatology Life Quality Index. Both, urticaria activity and QoL were determined before and after a 3-week period, in which the patients followed a pseudoallergen-low diet. Results: Urticaria activity score values correlated positively, albeit weakly, with QoL impairment in CU patients (r(2) = 0.31, P < 0.05). Also, changes in QoL following a pseudoallergen-low diet were reflected by the changes observed in the UAS (r(2) = 0.30, P < 0.05). No significant differences were found comparing the QoL correlation of the UAS and other symptom scores combining up to four CU symptom qualities. Quality of life correlation with UAS values increased with the number of days the UAS was assessed and plateaued starting from the fourth consecutive day. Conclusions: Our findings back the current guideline recommendations to use the UAS for monitoring disease activity in CU patients. Urticaria activity score mean values of at least four consecutive days should be used.