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?