Clinical Case 062: Vasculitis – making rash decisions?

This case is a bit backwards, as are a lot of things in medicine.

I am going to show you a picture – tell you what it is and then ask you to tell me where to next?  35 year old mother of 4 kids comes to see you with this rash.

Here is the image:                OK, this is a symmetrical lower limb, palpable purpura.  The RMO has already done a batch of tests looking for coagulopathy, thrombocytopenia, sepsis etc….  they are all plum normal other than a mildly raised CRP and ESR.

This is vasculitis, it looks and feels like vasculitis.  The patient is otherwise well aside from an associated mild effusion of the left ankle which is mildly tender but not hot.




So here is the starting point – the patient looks like they have developed a new vasculitis.  This could be due to a whole range of diseases.  So now in order to make a diagnosis, look smart and help this patient what do you need to know next?

The diagnosis is always on the history (90% anyway)! Think of he causes of vasculitis and ask about their triggers and associated features. Infections: sepsis, viral – Hep B, are usually easy to pick – ask about fever, constitutional sxs, recent respiratory or gut symptoms. However, this patient had been “well” recently – no likely infectious syndrome on history.

The autoimmune diseases – SLE, PAN, Rh arthritis, Goodpasture’s, MCTD, etc – these all have a “syndrome” – other clinical features to tip you in that direction. So I would ask about: oral / mucosal ulcers, Raynaud’s, photosensitivity, joint symptoms, spontaneous miscarriages (more than 2?), undiagnosed anaemia, serositis: chest, pleurisy, abdo pain…  the list is long but a lot of these minor features will be missed unless directly asked.  Chest symptoms might direct you to Churg-Strauss, Wegener’s or Goodpasture’s if there is a cough, “new asthma”, haemoptysis etc.  Odd neurological symptoms might point to SLE, PAN or sarcoidosis

Drugs: many drugs can trigger an immune-mediated vasculitis, and some can cause a serum sickness picture – so ask about anything recent: antibiotics, herbal / OTC preps, anything new..

Family history may be useful : ask about the chronic inflammatory joint, bowel diseases.

Specifically looking for features of the above diseases could take all day – but there is no cheaper test than looking in all available orifices for clues – eyes, ears, mouth, nose is a good start. Palpating joins to elicit a pattern of arthralgia might reveal a syndrome.  The exam will largely be guided by the history.

A BP and urinalysis will help exclude any renal disease process, send some off to look for casts, protein etc.  

This is one of those scenarios where you could spend a bunch of money on tests if you don’t think too hard. There is a temptation to do a screening batch of immuno-markers – ANS, ANCA, Ro, La, Anti-Rh, CCP….. you can do a thousand of them!

I think this is not the best strategy (though often used) – my plan would be to call my friendly immunology / rheumatology guy and outline exactly what I have heard and seen – then do the tess they think will help to confirm the diagnosis or exclude the really bad ones.  These need to be directed by the clinical picture.

Xrays of affected joints occasionally show more chronic processes in action.

What about a biopsy?  Well this seems crazy on first thought but it might be really useful in a week if you are still scratching your head.  If you take an ellipse of he rash and ask for immunofluorescence etc then it might actually give a specific pattern.  I think this could be useful

OK, let me know your backwards approach to this in your practice.   Casey


  1. OK, I’ll bite…

    She’s got new onset of palpable purpura. So it’s a leucocystoclastic vasculitis – might be idiopathic, might be drug-related, might be a manifestation of malignancy or infection…but the big one is gonna be rheumatological.

    Whenever I think rheumatology I think of those overlapping Venn diagrams we did at school, and the inevitable overlap of symptoms and tests in all of these.

    So, first thing is go back to history – any new drugs, any recent infections, any relevant family history (particularly of rheum disease), and systemic features like joint pain, fever, rash, weight loss…this os one of those cases where going back on a ‘med student’ type clerking can turn up trumps.

    Next up, exam findings…well, going to have a good guddle around in ENT exam Is this Streptococcal), rheum exam (inc heart for new murmurs) looking for joint involvement and dipstick the urine. Palpate the spleen.

    And now tests…well, depends on what I’ve found so far. The fact she’s not got a bleeding tendency is reassuring. But depending on history and exam, she may need screening for BBV eg: EBV, HCV, well as ASOT and throat swab. If history and exam makes rheum more likely then she’ll need ANCA and complement, maybe even cryoglobulins. Heck, she may even need a skin biopsy…

    And lastly, safety net – can she leave the ED/my rooms today safely? Does she need on referral? And if so, how long can this wait?

    This will, of course, depend on the answers in history and exam. I reckon the history will give the answers…

    OK, run out of steam now – over to the clever docs out there.

  2. Thanks Doc for this very interesting learning opportunity!

    A palpable purpura is usually a sign of inflammation of the vessels(vasculitis) as compared to a non palpable(macular) purpura is usually non inflammatory. Perhaps a quick blanching test can be done to differentiate among the two, with vasculitis lesions fail to blanch.

    I agree with the above that the possible causes Vasculitis are plenty. As you might know, Vasculitis can be further classified based on the size of vessels involved(the very popular chapel hill classification). It is mainly divided into big, medium and small vessel vasculitis.Since we are seeing cutaneous involvement here, we can be fairly convinced that this is probably small vessel vasculitis. There are 4 main types

    1) ANCA associated(Wegener)
    2) Immune complex associated (SLE,Henoch Scholein)
    3) Paraneoplastic/infection
    4) inflammatory bowel disease

    In my humble opinion, the next big step now is to look for systemic involvement particularly renal involvement, since the patient complained of swollen ankle.We can start with a humble blood pressure, urinalysis for proteinuria and hematuria(nephritic presentation), urea, creat and electrolytes..That having said, renal involvement can be present in so many of the associated conditions as well, it can occur in lupus nephritis, WG and CHrig Strauss can cause rapidly progressive glomerulonephritis..nothing is specific, but perhaps a serum ANCA can help

    Look for associated upper airway problems that could suggest wegener granulomatosis.
    SLE features like malar rash, joint pain(there are so many of them)
    Diarrhoea, significant weight loss to suggest IBD
    Stigmata of infections to suggest Hepatitis, streptococcal infection
    Joint pain, abdominal pain, renal impairment to suggest HSP, although very rare in adults

    Tough one, please enlighten us on the final diagnosis

  3. @NoGreatMischief: @broomedocs An enteritis such as Campylobacter or Shigellosis with reactive arthritis? What do the local kids have? Does she have eggs from her own chooks or have a house dairy cow? Or have possum poo in her tank water?

  4. History, innit?

  5. I had the same type of case except the boy was complaining of wrist pain after ” being hit with a volley ball in his wrist” After noticing joint swelling looking like a fracture, and a normal xray i was surprised. I asked if anything else was bothering him and he said he had a few mosquito bites! Then he showed me his legs and i saw this amazing rash on his legs of a deep red non blanching rash!
    His working diagnosis was HSP and i sent him home granted he did not have any gi bleeding or renal impairment.

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