Unexplained Bruising: Causes, Symptoms & When to See a Doctor

Spontaneous or disproportionate bruising (ecchymosis) warrants systematic evaluation for hemostatic, vascular, or systemic pathology.

Hemostatic Causes

• Thrombocytopenia: Platelets <100k (ITP, TTP, HIT, DIC, marrow failure, sequestration, drugs). Petechiae, mucosal bleeding.
• Coagulopathy: Factor deficiencies (hemophilia, acquired — liver disease, vitamin K deficiency, warfarin, DOACs), DIC.
• Von Willebrand Disease: Most common inherited bleeding disorder. Mucocutaneous bleeding.
• Platelet Function Defects: Uremia, aspirin/NSAIDs, antiplatelets, myeloproliferative neoplasms.

Vascular / Connective Tissue

• Vasculitis: Palpable purpura (leukocytoclastic, HSP, PAN, cryoglobulinemic).
• Hereditary Hemorrhagic Telangiectasia (HHT): Telangiectasias, epistaxis.
• Ehlers-Danlos (Vascular Type): Fragile vessels, organ rupture.
• Scurvy (Vitamin C Deficiency): Perifollicular hemorrhages, corkscrew hairs, poor wound healing.
• Corticosteroid / Aging Skin: Atrophy → senile purpura (forearms/hands).

Systemic / Malignant

• Leukemia / Lymphoma / Myeloma: Marrow infiltration → thrombocytopenia; paraprotein interference.
• Liver Disease: ↓ Factor synthesis, thrombocytopenia (splenomegaly).
• Renal Failure: Uremic platelet dysfunction.
• Infections: Sepsis (DIC), endocarditis, viral (dengue, EBV, CMV, HIV).

Mechanical / Factitious

• Trauma (forgotten, sports), suction (cupping), self-inflicted (factitious disorder), anticoagulant rodenticide exposure.

Red Flags (Urgent Evaluation)

• Large, expanding, painful bruises.
• Mucosal bleeding (epistaxis, gum, GI, GU).
• Petechiae (non-blanching pinpoint spots).
• Associated: fever, weight loss, night sweats, bone pain, lymphadenopathy.
• On anticoagulants with INR >4.5 or bleeding.
• Child/elder with bruising pattern suggestive of abuse.

Workup

CBC + smear, PT/INR, aPTT, fibrinogen, D-dimer, LFTs, renal panel, vitamin C, factor assays, VWF panel, SPEP/immunofixation, bone marrow if indicated.