DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


What is purpura?

Purpura is the name given to the discolouration of the skin or mucous membranes due to haemorrhage from small blood vessels.

Extravasated blood usually breaks down and changes colour over a few weeks from purple, orange, brown and even blue and green.

Classification of purpura

There are many different types of purpura. Their classification depends on the appearance or cause of the condition.

Platelet disorders Thrombocytopaenic purpura—due to destruction of platelets
  • Primary (idiopathic) thrombocytopaenic purpura due to autoimmune or unknown reasons
  • Secondary thrombocytopaenic purpura due to external or internal factors such as drugs, infections, systemic diseases
Other coagulation disorders
  • Disseminated intravascular coagulation – clinical picture varies from a severe and rapidly fatal disorder (purpura fulminans) to a relatively minor disorder
  • Heparin-induced thrombocytopaenia – purpura and necrosis due to anti-platelet antibodies inducing platelet plugs that block blood vessels
  • Warfarin-induced necrosis – purpura and necrosis due to blood clots related to relative protein C deficiency early in treatment
Vascular disorders Non-thrombocytopaenic purpura—leakage of blood through the vessel wall
  • Damage to small blood vessels
  • Increase in intraluminar pressure
  • Deficient vascular support, as in aged or sun damaged skin (senile purpura)

What are the signs and symptoms of purpura?

The signs and symptoms of purpura vary according to the type of purpura. The following broad generalisations may be made.

Suction bruise
Venous stasis
Steroid purpura
Disseminated intravascular coagulation

What is the treatment for purpura?

The underlying cause of purpura should be identified and treated accordingly.

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Author: Vanessa Ngan, staff writer, 2005. Updated by Hon A/Prof Amanda Oakley, November 2015.

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