purpuric rash

Headline
History if unwell - ask about bone marrow suppression (infections, bruising)
➥ DHx*, recent infection, immunisation
➥ personal/family history of mucosal bleeding
Examination
Diagnostic investigations FBC, coag screen
Urine dip
Differentials unwell → acute leukaemia, meningococcal sepsis
If well + abnormal bloods: Immune thrombocytopenic purpura/Thrombotic thrombocytopenic purpura, pancytopaenias, clotting disorders
If well + normal bloods: senile purpura, raised SVC pressure, vasculitis (Henoch Schonlein purpura, NAI.