A blood clot is a collection of blood cells and proteins inside a blood vessel.
Blood clotting is a natural bodily process that allows injuries to heal. However, clots can form without an injury or fail to break down naturally after an injury has healed. This can lead to severe and potentially life threatening complications.
This article explains whether it is possible for someone to feel a blood clot, other symptoms to be aware of, and tips for preventing blood clots.
Can a person feel a blood clot?
A person may be able to feel certain types of blood clots by touch. However, the most dangerous blood clots occur deep inside the body, meaning a person cannot see or touch them but may be able to feel them in other ways.
Superficial thrombophlebitis is a condition in which a vein close to the skin’s surface becomes inflamed due to a blood clot forming within the vein.
According to the United Kingdom’s National Health Service (NHS), a person with this condition may be able to see and feel the inflamed vein beneath the skin.
Other types of blood clots form in veins deeper inside the body, meaning a person will not be able to see them or feel them by touch. Examples include deep vein thrombosis (DVT) and pulmonary embolism.
DVT is when clots form within deep veins of the body, most commonly those in the thigh, calves, or pelvis. Pulmonary embolism is a clot that blocks and prevents blood flow to the lung.
Other warning signs of a blood clot
As many as 50% of people with acute DVT will not experience any symptoms at all.
When DVT symptoms do occur, they may be localised to the part of the body containing the clot and often include:
- pain or tenderness
- swelling
- skin redness or discoloration
- prominent veins
People with superficial thrombophlebitis may feel a firmness or thickening of the vein, known as a “cord”, where the clot occurs.
Emergency blood clot symptoms
DVT can be life threatening, as fragments of the clot may break away and travel through the bloodstream to other parts of the body, such as the lungs. When this occurs, it can cause a pulmonary embolism.
In some people, a pulmonary embolism may be the first indication of DVT.
Possible signs and symptoms of a pulmonary embolism include:
- rapid or irregular heartbeat
- difficulty breathing
- chest pain or discomfort, which typically worsens when breathing deeply or coughing
- coughing up blood
- lightheadedness or fainting, due to very low blood pressure
A pulmonary embolism is a medical emergency. Anyone who experiences symptoms should seek immediate medical care.
How long can someone have a blood clot without knowing?
Although around half of people with DVT do not experience symptoms, they may still be at risk of complications from blood clots.
As such, it is difficult to know how long a person can have DVT before developing symptoms.
Who is at risk of blood clots?
According to the Centers for Disease Control and Prevention (CDC), almost anyone may develop DVT, but the following factors can increase the risk:
- slow blood flow due to:
- limited movement
- long periods of inactivity
- paralysis
- injury to a vein, such as from:
- a fracture
- a severe muscle injury
- major surgery
- increased estrogen, such as from:
- certain chronic medical conditions, such as:
Smoking, having obesity, and advanced age can also increase the risk of blood clots.
Preventing blood clots
Maintaining or achieving a moderate weight and getting regular exercise can lower a person’s risk of blood clots.
The American Heart Association recommends the following strategies for helping to prevent blood clots during extended periods of immobility, such as during hospitalization or long-distance air travel:
- Moving around:Â As long as it is safe to do so, a person should move around regularly to promote blood flow. This may involve exercises to flex the legs and ankles or changing position frequently.
- Wearing compression devices:Â Graduated compression stockings and massaging compression devices can promote blood flow. However, a person should first ask their doctor whether these devices are safe for them to use.
- Taking prescription medications:Â Doctors may recommend anticoagulant medications for people at high risk of developing blood clots. However, these medications are not suitable for people at high risk of bleeding.
When to contact a doctor
Anyone who develops symptoms of DVT or pulmonary embolism should seek emergency medical treatment. Timely treatment can reduce the risk of complications, including death.
In addition, people who develop symptoms of superficial thrombophlebitis should also contact their doctor.
Although this condition is rarely dangerous, recent research associates it with a higher risk of serious conditions, including DVT, pulmonary embolisms, and cancerous cells.
Summary
A blood clot is a collection of blood cells and proteins inside a blood vessel. Superficial thromboses are clots that develop in blood vessels close to the skin’s surface, and these may cause symptoms that a person can see and feel.
Deep vein thromboses are clots that develop in blood vessels deep inside the body, and these may cause symptoms that a person can feel in other ways.
Anyone who experiences symptoms of a blood clot should seek emergency medical attention.
- Czysz A, et al. (2023). Superficial thrombophlebitis.
https://www.ncbi.nlm.nih.gov/books/NBK556017/ - Deep vein thrombosis. (2021).
https://orthoinfo.aaos.org/en/diseases–conditions/deep-vein-thrombosis/ - Phlebitis (superficial thrombophlebitis). (2022).
https://www.nhs.uk/conditions/phlebitis/ - Prevention and treatment of venous thromboembolism. (2023).
https://www.heart.org/en/health-topics/venous-thromboembolism/prevention-and-treatment-of-venous-thromboembolism-vte - Pulmonary embolism. (n.d).
https://www.lung.org/lung-health-diseases/lung-disease-lookup/pulmonary-embolism - Venous thromboembolism (blood clots). (2023).
https://www.cdc.gov/ncbddd/dvt/index.html - Vyas V, et al. (2022). Acute pulmonary embolism.
https://www.ncbi.nlm.nih.gov/books/NBK560551/ - Waheed SM, et al. (2023). Deep vein thrombosis.
https://www.ncbi.nlm.nih.gov/books/NBK507708/