What is the diagnosis for a patient presenting with ecchymosis (bruising) and redness on their arm?

Terminology for Redness Resembling Bruising on the Arm

The medical term for redness on the arm that resembles bruising is "ecchymosis," which refers to discoloration of the skin caused by extravasated blood in the dermis and/or subcutaneous tissue. 1, 2

Definition and Clinical Description

• Ecchymosis is the precise medical terminology for large areas of discoloration caused by blood extravasation into subcutaneous tissue 1, 2
• This differs from petechiae (pinpoint hemorrhages) or purpura (smaller areas of bleeding), which are distinct clinical entities 3
• The term "bruise" is the lay terminology, while ecchymosis is the formal medical descriptor used in clinical documentation 2

Key Diagnostic Considerations When Evaluating Ecchymosis

When a patient presents with ecchymosis, the clinical evaluation must distinguish between traumatic and non-traumatic causes:

Traumatic vs. Non-Traumatic Differentiation

• If the caregiver's description of trauma sufficiently explains the bruising, or if there is witnessed trauma, no bleeding disorder evaluation is typically needed 3
• Non-traumatic ecchymoses can occur as symptoms of underlying disease, clinical conditions, or during disease treatment, and must be distinguished from traumatic causes 1

Critical Red Flags Requiring Immediate Evaluation

• Spontaneous ecchymosis without clear trauma history requires immediate bleeding disorder testing in adults, including CBC, PT, aPTT, and von Willebrand factor testing 4, 5
• Normal PT and aPTT do not rule out bleeding disorders, as these tests detect only approximately 50% of coagulation disorders 5
• Von Willebrand disease is frequently missed because it is not reliably detected by standard PT/aPTT screening 4, 6

Specific Historical and Physical Examination Elements

The focused evaluation should assess for:

• Spontaneous versus traumatic onset, medication use (especially NSAIDs and antiplatelet agents), family history of bleeding disorders, associated bleeding symptoms, nutritional status, and alcohol use 5
• Fever, bone or joint pain, lymphadenopathy, hepatosplenomegaly, or abnormal blood counts suggest alternative diagnoses beyond simple ecchymosis 3
• In immunocompromised patients, infectious etiologies such as ecthyma gangrenosum or necrotizing fasciitis must be considered and require urgent biopsy and broad-spectrum antibiotics 5

Common Clinical Pitfalls

• Assuming normal coagulation studies exclude bleeding disorders is a critical error, as mild factor deficiencies and platelet function disorders may not prolong aPTT 4, 6
• Von Willebrand factor is an acute phase reactant and can be falsely elevated during stress or illness, necessitating repeat testing if clinical suspicion remains high 4
• Failure to correctly identify non-traumatic ecchymoses may lead to inappropriate abuse investigations or missed serious underlying pathology 1

When to Consult Hematology

• Consultation with hematology should occur if initial screening tests show abnormalities, bleeding symptoms persist despite normal initial testing, or specialized testing is needed 4, 5
• Referral is particularly important when there is recurrent spontaneous bruising with or without mildly prolonged aPTT 6