Purpuric and petechial rashes in adults and children: initial assessment

Abstract

#### What you need to know 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. 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. Patients with purpura can generally …