What should you know about deep vein thrombosis in the arm?

An arm DVT can develop in a vein of the upper arm, shoulder or chest. The clot may slow the return of blood towards the heart, causing swelling, aching, heaviness, warmth or a change in skin colour on one side. Some people have few symptoms, so appearance alone cannot confirm or exclude a clot. A clinician may consider recent surgery, reduced movement, a vein catheter, cancer, pregnancy, hormone medicines or a previous clot when assessing risk, but an arm DVT can occur without an obvious trigger.

Diagnosis usually involves an examination and an ultrasound scan of the veins. Other tests may be needed when the clot is higher in the chest or when the diagnosis remains uncertain.

Arrange prompt medical assessment for new one-sided arm swelling, pain, warmth or unexplained heaviness, particularly after an operation, prolonged immobility or insertion of a line. Do not massage the swollen area or start, stop or share blood-thinning medicine without clinical advice. If a clot is confirmed, treatment commonly includes an anticoagulant chosen around your health, kidney function, other medicines and bleeding risk. Take it exactly as prescribed and tell the treating team about bleeding, missed doses and any planned procedure.

Call emergency services immediately for sudden breathlessness, chest pain that may worsen with breathing, coughing blood, fainting or a fast, irregular heartbeat. These symptoms can indicate that a clot has travelled to the lungs. Seek urgent assessment as well if arm swelling rapidly worsens, the hand becomes cold or markedly discoloured, or pain becomes severe. Do not drive yourself if you feel faint or short of breath.

Ask what test is needed, where the suspected clot is located, how long treatment is expected to continue, which warning signs of bleeding require help, and whether any medicine, activity or procedure should be avoided while you recover.