Practice Practice Pointer

Purpuric and petechial rashes in adults and children: initial assessment

BMJ 2016; 352 doi: https://doi.org/10.1136/bmj.i1285 (Published 22 March 2016) Cite this as: BMJ 2016;352:i1285
  1. Angela E Thomas, consultant paediatric haematologist1,
  2. Susan F Baird, consultant paediatric haematologist1,
  3. Julia Anderson, consultant haematologist2
  1. 1Department of Haematology, Royal Hospital for Sick Children, Edinburgh EH9 1LF, UK
  2. 2Department of Haematology, Edinburgh Royal Infirmary, Edinburgh, UK
  1. Correspondence to: A E Thomas angela.thomas2{at}nhs.net

What you need to know

  • Assess all patients with suspected purpura for features of serious illness

  • If invasive meningococcal disease is suspected, administer parenteral antibiotics immediately, but do not delay hospital admission

  • In all other patients, severe thrombocytopenia must be excluded. Immediately refer children and young people for assessment; adults should have a full blood count and coagulation screen within 48 hours

Bleeding into the skin or mucosa from small vessels produces a purpuric rash, or smaller petechiae (1-2 mm in diameter). Purpura is not a diagnosis but can be the presenting feature of serious conditions, such as meningococcal sepsis and acute leukaemia, which require urgent diagnosis and management. Equally, it can cause patients alarm but requires little more than a single assessment and reassurance. Differentiating between the two scenarios is important. This article focuses on recognition of the serious diagnoses and recommendations for urgent referral. Once such diagnoses have been excluded, other causes can be investigated or the patient managed by observation alone.

Is the rash purpuric?

A cardinal sign of a purpuric rash is that it does not blanch on pressure, unlike exanthema, telangiectases, or allergic rashes. This sign of meningococcal sepsis has been the subject of public health campaigns to help parents recognise its importance and seek urgent medical attention (fig 1).

Fig 1 Petechial rash in invasive meningococcal disease

It is crucial to assess for features of serious illness in all patients with purpura.

What can cause a purpuric rash?

Patients with purpura can generally …

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