DVT Warning: Red, hot, swollen painful leg
A new swollen, painful or unusually warm leg, especially on one side, needs urgent medical assessment. It may be a deep vein thrombosis, or DVT: a blood clot in a vein deep inside the leg. Not everyone has every symptom, and you should not wait for a complete checklist before seeking help.
In this video, I explain why this combination matters, which situations can increase the risk of a clot and how an ultrasound scan helps investigate it. The message is straightforward: do not dismiss a sudden change as ordinary tiredness or your usual leg swelling.
What symptoms can a DVT cause?
Possible symptoms include:
Swelling: commonly affecting one leg more than the other.
Pain or tenderness: often in the calf or thigh, without an obvious explanation.
Warmth: an affected area that feels hotter than usual.
A change in skin colour: including redness or darker colouring, which may be less obvious on some skin tones.
Other conditions, such as infection, injury or inflammation, can produce similar symptoms. Some people with DVT have few or no obvious signs. This is why appearance alone cannot confirm or exclude a clot. Our DVT information page explains the condition in more detail.
Why can a clot in the leg affect the lungs?
A DVT can interfere with blood drainage from the leg. If part of the clot breaks away, it can travel through the circulation and lodge in the blood vessels of the lungs. This is called a pulmonary embolism (PE), which can be life-threatening.
Sudden breathlessness, chest pain, coughing blood, fainting or collapse require emergency assessment. These symptoms can occur even without obvious leg symptoms. In Singapore, call 995 for a life-threatening emergency. Do not wait for a clinic appointment or an online reply.
Who has a higher risk of DVT?
In the video, I highlight cancer, some blood conditions, long-haul travel, periods of immobility and major orthopaedic surgery. These situations may increase the tendency for blood to clot or reduce its movement through the leg veins.
Previous DVT, pregnancy and the period after childbirth, and some hormone treatments are also relevant. Several risks can occur together. However, DVT can happen without an obvious trigger, so the absence of a recent flight or operation is not a reason to ignore symptoms.
Long journeys by car, bus or train can also involve prolonged sitting. The concern is not unique to flying; limited movement and a person’s underlying risk both matter.
How is a suspected DVT assessed?
A clinician will ask about the symptoms, examine the leg and review your risk factors. A venous duplex ultrasound is a common first-line imaging test. It examines the deep veins and helps identify a clot and its location.
Depending on the clinical assessment, blood tests or further imaging may also be needed. If symptoms persist or change after an initial assessment, follow the advice given about reassessment. A scan result needs to be interpreted alongside the full clinical picture.
What happens if a DVT is confirmed?
Treatment commonly involves anticoagulant medicines, often called blood thinners. They help stop the clot extending and reduce the risk of further clots while the body deals with the existing clot. The medicine and duration depend on factors such as the clot’s location, cause and bleeding risk.
Some patients need additional specialist treatment. Follow-up also considers ongoing swelling or discomfort and whether there are underlying factors to address. A new suspected clot needs urgent care, rather than treatment based only on information in a video.
What can you do before a long journey?
Move your legs regularly and take opportunities to walk when safe. Keeping normally hydrated is sensible, but drinking water alone should not be regarded as protection against a travel-related clot.
If you have had a clot, recent surgery, cancer or another significant risk factor, discuss travel precautions with your clinician beforehand. Compression stockings or preventive medicines are appropriate for selected people and should be individually advised.
DVT assessment in Singapore
Seek urgent medical care for new one-sided painful swelling. For non-emergency questions about previous DVT or ongoing venous care, contact Andrew Choong Vascular Surgery at Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563.
This article provides general education and does not replace an individual medical assessment.