Hi, had itchy hives all over my body due to a body wash. i was giving oral steroid, prenisone. the itch stopped. it came back after 9 hr. how come?

Hives: Hives all over the body is a systemic reaction to an allergy. The prednisone works to reduce the systemic effects of this allergy. The half-life of prednisone, ( the time it takes for 1/2 of it to be gone from the body) is 3-4 hours. In some people, the half-life is even less time. The dose of the prednisone may be too low for you and could have lost its effects too early. Speak to your doctor.