Makindo Medical Notes

Purpura is a sign of an underlying issue with blood vessels, platelets, or the coagulation system. The cause can range from benign conditions like minor trauma to life-threatening disorders such as DIC or leukaemia. A thorough history, physical examination, and targeted laboratory investigations are essential for diagnosing the underlying cause and guiding appropriate management.

What is it

• Petechiae: Small, pinpoint red or purple spots (less than 3 mm).
• Ecchymoses: Larger patches (greater than 1 cm), commonly referred to as bruising.

Why Does Purpura Happen?

Purpura occurs when blood leaks from small blood vessels into the skin, mucous membranes, or other tissues. The underlying causes of purpura can be categorized into:

• Vascular Causes: Damage or inflammation of blood vessels (e.g., vasculitis).
• Platelet Disorders: Low platelet count (thrombocytopenia) or impaired platelet function (e.g., immune thrombocytopenic purpura).
• Coagulation Disorders: Deficiencies in blood clotting factors (e.g., disseminated intravascular coagulation, DIC).
• Trauma: Physical injury to small vessels causing them to rupture.
• Medications: Certain medications (e.g., anticoagulants, steroids) can impair clotting or cause vessel fragility.

Table of causes

Clinical History

• Onset and Duration: Sudden or gradual onset helps differentiate between acute (e.g., trauma, infection) or chronic conditions (e.g., vasculitis, malignancy).
• Associated Symptoms: Check for fever, joint pain, fatigue, bleeding from other sites (e.g., gums, nosebleeds), or renal involvement (haematuria).
• Drug History: Review medications such as anticoagulants or steroids that may cause purpura.
• Family History: Investigate inherited bleeding disorders like haemophilia or von Willebrand disease.

Physical Examination

• Distribution: Determine whether the purpura is localized or generalized. Palpable purpura may indicate vasculitis.
• Size: Differentiate between petechiae (small spots) and ecchymoses (larger bruises).
• Systemic Signs: Check for lymphadenopathy, splenomegaly, or signs of systemic infection.

Laboratory Tests

• Full Blood Count (FBC): To assess platelet count and anaemia.
• Coagulation Profile: Evaluate prothrombin time (PT), activated partial thromboplastin time (aPTT), and clotting factors.
• Peripheral Blood Smear: Look for abnormal cells like schistocytes (TTP) or blast cells (leukaemia).
• Liver Function Tests: If liver disease or clotting factor deficiency is suspected.
• Autoimmune Markers: ANCA or ANA tests for vasculitis or autoimmune disorders.
• Renal Function Tests: Urinalysis and serum creatinine to check for kidney involvement in vasculitis.

Management: treatment for purpura depends on its underlying cause

• Thrombocytopenia (e.g., ITP): Steroids, intravenous immunoglobulin (IVIG), or splenectomy in refractory cases.
• Vasculitis: Corticosteroids and immunosuppressants to control inflammation.
• DIC: Treat the underlying cause (e.g., sepsis), along with supportive therapies like fresh frozen plasma.
• Trauma: No specific treatment is required other than treating the injury.
• Nutritional Deficiency: Vitamin supplementation (e.g., vitamin C for scurvy).