<prompt> In HenochSchonlein purpura renal involvement is not seen generally if no involvement till ?1 month after onset2 month after onset3 month after onset4 month after onset  <response>: Renal involvement occurs in 20 to 50 of HSP, usually within 4 weeks of presentation, and less commonly precedes the other symptoms.The onset of abnormalities may follow the onset of other symptoms by weeks 80 within 4 weeks or even months 97 within 3 months.Coming back to questionAccording to me the best answer is 4 months because renal involvement may be seen up to 3 months after the onset of other symptoms examiner is asking about the renal involvement after onset of disease, not after the onset of other symptoms.Renal manifestations usually start at the onset or within 3 months of the onset of other symptoms Pediatric nephrologyOther symptoms, e.g. rash, will also take some time to appear after the onset of disease. Thus, renal involvement may occur up to more than 3 months after onset of the disease. 