Purpura

Probability diagnosis

Simple purpura (easy bruising syndrome)

Senile purpura

Corticosteroid-induced purpura

Immune thrombocytopenic purpura

Henoch–Schönlein purpura

Serious disorders not to be missed

Malignant disease:

• leukaemia

• myeloma

Aplastic anaemia

Myelofibrosis

Infection:

• septicaemia

• meningococcal infection

• infective endocarditis

• measles

• typhoid

• dengue/chikungunya

• other tropical haemorrhagic viral infections

Disseminated intravascular coagulation

Thrombotic thrombocytopenic purpura

Fat embolism

Kidney failure

Pitfalls (often missed)

Haemophilia A, B

von Willebrand disease (vW)

Post-transfusion purpura

Trauma (e.g. domestic violence, child abuse)

Rarities:

• hereditary telangiectasia (Osler–Weber–Rendu syndrome)

• Ehlers–Danlos syndrome

• scurvy

• Fanconi syndrome

Masquerades checklist

Drugs:

• chloramphenicol

• corticosteroids

• sulphonamides

• quinine/quinidine

• thiazide diuretics

• NSAIDs

• cytotoxics

• oral anticoagulants/heparin

Anaemia:

• aplastic anaemia

Psychogenic factors

Factitious purpura (intentionally pinching skin)

Key history

Include family history, drug history and features of the purpura such as post trauma or spontaneous, recurrent episodes of bleeding and whether any bleeding is out of proportion to the trauma.

Key examination

• Detailed examination of the skin, lips and oral mucosa, lymph node areas, abdominal examination with emphasis on spleen and liver

• Urinalysis searching for blood (microscopic or macroscopic) is important

Key investigations

FBE and blood film

• If coagulation defect suspected:

  • - prothrombin time i.e. INR

  • - activated partial thromboplastin time

  • - fibrinogen level

  • - thrombin time.

• If platelet pathology suspected:

  • - platelet count

  • - platelet function analyser (PFA-100).

• If inherited disorders suspected:

  • - factor VIII

  • - vW factory activity

  • - vW factor antigen.

Diagnostic tips

• Platelet abnormalities present as early bleeding following trauma.

• Coagulation factor deficiencies present with delayed bleeding after initial haemostasis is achieved by normal platelets.

• A normal response to previous coagulation stresses (e.g. dental extraction, circumcision or pregnancy) indicates an acquired problem.

• If acquired, look for evidence of MILD: malignancy, infection, liver disease and drugs.