A 23-year-old man is receiving penicillin for the treatment of a group A strep throat infection. He now returns to the clinic with new symptoms of a rash and diffuse joint discomfort. On physical examination, there are areas of urticaria on his arms and back. The joints appear normal and he has no oral lesions. A urinalysis is positive for red cell casts and protein. Which of the following is most characteristic of the syndrome?
it usually requires corticosteroids symptoms last several months it may recur after apparent recovery it may be transferred by leukocyte infusions