Must be willing to fill out a twice-daily patient-diary to establish the patient's Urticaria Activity Score 7 (UAS7) score. The UAS is a composite diary- recorded score with numeric severity intensity ratings (0 = none to 3 = intense) for 1) the number of wheals (hives); and 2) the intensity of the pruritus (itch). The UAS7 is the sum of the daily average UAS scores (average of a.m. and p.m.) for 7 days. The maximum UAS7 value is 42.