delayed pressure urticaria delayed pressure urticaria delayed pressure urticaria is known as one of the more painful subsets of physical urticaria due to formed hives being deep-seated and appearing after 4–6 hours. causes due to the delayed appearance of wheals, plausible causes are hard to establish; the natural course and/or clinical pattern is variable and inconclusive. treatment it was noted that although antihistamines and anti-inflammatory drugs such as, colchicine, sulphasalazine, dapsone, and topical steroid are advocated for in the treatment of dpu, most if not all are unsatisfactory in relieving symptoms. even a second generation antihistamine, ketotifen, was unable to efficiently and satisfactorily relieve symptoms of dpu