The National Health Service has issued an urgent alert to the public, advising them to contact NHS 111 immediately if they detect a specific and potentially dangerous symptom affecting just one leg. This warning sign could indicate a deep vein thrombosis (DVT), a blood clot with the potential to cause life-threatening emergencies like strokes and heart attacks.
Understanding the Danger of Blood Clots
While blood clotting is a natural and vital process that prevents excessive bleeding from injuries, problems arise when clots do not dissolve on their own. These obstructions can travel through the bloodstream, leading to severe complications by blocking blood flow to critical organs. The NHS explicitly states, "Blood clots can be very serious and need to be treated quickly."
The condition often begins when a clot forms in a deep vein, typically in the leg or arm. This is known as deep vein thrombosis. A key indicator of DVT is a throbbing or cramping pain, usually located in the calf or thigh. This discomfort often becomes more noticeable when walking or standing. Crucially, the NHS notes that this symptom "rarely" occurs in both legs at the same time.
Recognising the Symptoms of DVT
Beyond a throbbing pain, there are several other symptoms to watch for in the leg. These include:
- Swelling in one leg (it is rare for both legs to be affected)
- Skin that feels warm around the painful area
- Red or darkened skin around the painful spot – the NHS adds that this may be harder to see on brown or black skin
- Swollen veins that feel hard or sore to the touch
The health service clarifies that these symptoms can also manifest in your arm or tummy if the blood clot is located there. If you suspect you may have DVT, the NHS recommends that you "ask for an urgent GP appointment or get help from NHS 111" to reduce the risk of the clot triggering a more severe event.
When a Blood Clot Becomes a Medical Emergency
The NHS warning highlights the severe risks if a blood clot travels to the lungs, causing a pulmonary embolism. This is a life-threatening condition that requires immediate treatment. If you experience any symptoms of DVT alongside breathlessness or chest pain, you must call 999 or go directly to A&E.
"DVT can be very serious because blood clots can travel to your lungs," the NHS emphasises. "This is called a pulmonary embolism. A pulmonary embolism can be life-threatening and needs treatment straight away."
In such an emergency, you are advised not to drive yourself to the hospital. Instead, ask someone to drive you or call 999 for an ambulance.
Several factors can increase an individual's risk of developing a blood clot. These include being over 60, overweight, or a smoker. A previous history of DVT, using the contraceptive pill or hormone replacement therapy, and having conditions like cancer or heart failure also elevate the risk. Certain situations, such as being in hospital with limited mobility, taking long journeys (over three hours), being pregnant, or suffering from dehydration, can further increase the chances of DVT developing, though it can sometimes occur for "no obvious reason."
To lower your risk, the NHS suggests maintaining a healthy weight, staying active with regular walks, and ensuring you are properly hydrated. It is also important to avoid sitting still for long periods, try not to cross your legs when seated, and reduce alcohol consumption and smoking. If diagnosed, treatment may involve anticoagulant medicines like warfarin or, in some cases, surgery.
