Endgames Picture Quiz

Petechial rash on the extremities

BMJ 2009; 338 doi: http://dx.doi.org/10.1136/bmj.b1284 (Published 15 April 2009) Cite this as: BMJ 2009;338:b1284
  1. Stephanie St Pierre, medical student1,
  2. Marisa Potter, dermatology resident2,
  3. Scott P Prawer, dermatology resident (graduated), dermatologist23,
  4. Pitiporn Suwattee, assistant professor of dermatology4
  1. 1University of Minnesota Medical School, Minneapolis, MN, 55455 USA
  2. 2Department of Dermatology, University of Minnesota, Minneapolis, MN, 55455 USA
  3. 3Private Practice, Fridley, MN, 55432 USA
  4. 4Minneapolis Veterans Affairs Medical Center, Minneapolis, MN, 55417 USA
  1. Correspondence to: P Suwattee suwat001{at}umn.edu

    A 53 year old, afebrile woman presented to the dermatology clinic with a two week history of petechial rash on her lower extremities that had progressed up to her arms. In addition, she also had pain in the wrists, knees, and elbows. Approximately five months earlier, she had been diagnosed with group A streptococcal pharyngeal infection, but she had not been treated with antibiotics. She was currently taking salbutamol, famciclovir, levothyroxine, lovastatin, and varenicline. A systems review was unremarkable and she had no reported haematuria, abdominal pain, or bloody stools.

    A physical examination found multiple petechial macules, papules, and purpuric plaques, which were more numerous on the legs than on the arms (figure[F1]). A complete blood count and coagulation studies were normal. Urinalysis showed haematuria and proteinuria. A skin biopsy of a petechial papule revealed leucocytoclastic vasculitis, with a granular IgA reactivity around the blood vessels in the papillary dermis.

    Questions

    • 1 What additional investigative studies could be useful in a patient with palpable purpura?

    • 2 What is the most likely diagnosis in our patient?

    • 3 What are the adverse sequelae of this disease?

    Answers

    Short answers

    • 1 Additional studies should include a faecal occult blood test, serology for hepatitis B and C, serum protein electrophoresis, anti-streptolysin O titre, and measurement of antinuclear antibodies, antineutrophil cytoplasmic antibodies, rheumatoid factor, serum immunoglobulins, and cryoglobulins. Abdominal ultrasound and renal biopsy may also be indicated.

    • 2 The most likely diagnosis is Henoch-Schönlein purpura or anaphylactoid purpura, a leucocytoclastic vasculitis of small vessels.

    • 3 Complications of Henoch-Schönlein purpura include nephritis or nephrotic syndrome, acute and chronic renal failure, gastrointestinal bleeding, intussusception, bowel obstruction, and bowel perforation.

    Long answers

    1 Investigations

    Cutaneous palpable purpura may signify small vessel vasculitis, which has many possible causes (box 1).1 2 Histological findings of leucocytoclastic vasculitis include fibrin deposition in the vessel walls, red blood cell …

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