Good evening, i had an urticaria crisis about 2 weeks ago that lasted for two days. i had to take prednison and diphenhydramine. now when i take a sho?

Urticaria: if it was just an acute episode, then what you received should be fine to control it, but if you keep getting the crises, or if you had it for some time, like > 6 weeks, so it became chronic and needs evaluation by a specialist: a dermatologist or an allergist/immunologist. Meanwhile you can keep taking OTC cetirizine, loratadine, or fexofenadine, on regular basis, but read the labels carefully