Rash decision OSCE by Adam

You have 3 minutes reading time. This OSCE will run for a maximum of 7 minutes.


Cassandra is a 55F who presents with a three day history of chills, malaise and a widespread rash.

View attached:  Attachment 1  Attachment 2

Instructions for the candidate

1. Please take a history from the patient.
2. Interpret the photographs provided
3. Provide a differential diagnosis.
4. Answer the examiners question.

Domains being examined

  • Medical Expertise
  • Prioritisation And Decision Making
  • Communication
  • Professionalism
The candidate has 3 minutes reading time. This OSCE is expected to run for a maximum of 7 minutes.

For the actor

- 3 days of general malaise, subjective fevers, feeling progressively unwell
- First noted a red rash to upper chest and neck, now spreading to back and upper arms
- The rash is tender, but not puritic
- Also developed ulcers in the mouth
- No rash on hands of feet
- No foreign travel
- No sick contacts
- No GI or resp symptoms
- Single regular sexual partner, husband of 25 years

- TBI 1 year ago following a car accident
- Epilepsy since TBI

- Hysterectomy

- Lamotrigine commenced a week ago
- Telmisartan


- Mother of 3
- Works for telstra, office
- Non smoker
- Occasional ETOH, 2-3 glasses wine per week
- Denies recreational drug use

For the examiner

1. Rash description:
- symmetric and widespread
- Erythematous
- Maculapapular coalescing lesions affecting chest, back, arms
- Some evidence of necrosis
- Evidence of mucosal involvement
- Target lesion appearance to some of the lesions

2. Differential:
- SJS, TEN ( EM less likely given surface area and mucosal involvement) SJS/Ten overlap ( 3-35% mortality)
- DRESS syndrome ( drug rash with eosinophilia and systemic symptoms)
- Toxic shock syndrome ( wide spread desquamating erythroderma involving hands and feet, with mucosal involvement. Staph and strep pyogenes)
- Staph Scolded skin syndrome ( more kids, no mucosal involvement)
- Bullous pemphigoid ( tense deep bullae, and no mucosal involvement, nikolsky negative, associated with lupus, drug reaction)
- Pemphigus vulgaris ( Flaccid, nikolsky positive, mucosal involvement) b cell lymphoma, RA, lupus, penicillamine.

3. Causes of SJS
- Antibiotics ( Sulphonamides ( note use in HIV elevates risk by 40x), Penicillins, Cephazolins.
- Anticonvulsants ( Phenytoin, lamotrigine, CBZ)
- Anti- inflammatories NSAIDS
- Allopurinol

- Others: HSV and mycoplasma (especially EM), Lymphoma, Leukaemia, HIV.

4. Management of SJS/Ten overlap
- stop offending agent
- Burns dressings
- Saline mouth washes
- analgesia
- Admit HDU, Burns unit, demratology
- Involve ophthalmology (70% occular involvement)
- IVIG and plasmaphoresis

Domains Assessment Objectives

Medical Expertise

Prioritisation And Decision Making



Other Assessment Notes

Obscure topic.
Recognition of severity.
Generation of a sensible differential for a desquamating erythematous rash with mucosal involvement.

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