Differential Diagnosis for Bruise on the Crease of Left Arm Spreading Up Arm

• Single Most Likely Diagnosis
  • Trauma or injury: The most common cause of a bruise is trauma or injury to the affected area, which can cause blood vessels to break and leak into the surrounding tissue, resulting in a bruise.
• Other Likely Diagnoses
  • Hematoma: A collection of blood outside of blood vessels, which can occur due to trauma or injury, and may spread up the arm.
  • Insect bite or sting: Certain insect bites or stings can cause bruising, especially if the individual has an allergic reaction.
  • Medication side effect: Certain medications, such as anticoagulants, can increase the risk of bruising.
• Do Not Miss Diagnoses
  • Deep vein thrombosis (DVT): Although less likely, a bruise that spreads up the arm could be a sign of a DVT, which is a blood clot in a deep vein that can be life-threatening if it breaks loose and travels to the lungs.
  • Septic thrombophlebitis: An infection of a vein that can cause a bruise-like appearance and can be life-threatening if not treated promptly.
• Rare Diagnoses
  • Vasculitis: Inflammation of blood vessels that can cause bruising, but is a rare condition.
  • Bleeding disorder: Certain bleeding disorders, such as hemophilia, can increase the risk of bruising, but are relatively rare.
  • Malignancy: In rare cases, a bruise can be a sign of an underlying malignancy, such as leukemia or lymphoma.