Intended for healthcare professionals

Endgames Spot Diagnosis

A boy with purpura on the legs

BMJ 2021; 372 doi: (Published 04 March 2021) Cite this as: BMJ 2021;372:n329
  1. Yan Song, nephrologist1,
  2. Qin Zhou, renal pathologist1,
  3. Jianjun Qiao, dermatologist2,
  4. Jianghua Chen, professor1
  1. 1Kidney Disease Center, The First Affiliated Hospital, Zhejiang University, Hangzhou, China
  2. 2Department of Dermatology, The First Affiliated Hospital, Zhejiang University, Hangzhou, China
  1. Correspondence to: J Chen azjukidney{at}

A boy in his mid teens presented to the dermatology department with a one week history of non-pruritic rash on his legs, and abdominal and bilateral knee pain. On examination, palpable purple papules were present on both legs, extending from the ankles to the thighs (fig 1). Other examination findings were unremarkable. The boy reported no history of upper respiratory tract infection in the four weeks before symptom onset. Table 1 shows the results of relevant blood and urine investigations.

Fig 1

Palpable purpura on lower legs

View this table:
Table 1

Results of relevant blood and urine investigations

Several conditions were considered unlikely: meningococcal sepsis, because of the absence of fever, neurological symptoms, and biomarkers of bacterial infection; thrombocytopenia, because the platelet count was within normal range; and coagulopathy, …

View Full Text

Log in

Log in through your institution


* For online subscription