Blood clots serve a critical biological purpose. They form after an injury to prevent the body from losing too much blood. The problem arises when a clot develops inside a vein or artery without any obvious injury to trigger it, or when it fails to dissolve on its own. Left untreated, clots can lead to serious, sometimes fatal, complications.
What makes them particularly dangerous is how unremarkable or entirely absent their symptoms can be. The signs vary widely depending on where in the body the clot has formed, whether that is the leg, lung, heart, brain, arm, or abdomen. Many of those symptoms overlap with far more common, less serious conditions, which is exactly why they go undetected so often. Here are seven signs that medical experts say deserve close attention.
Leg cramps that feel like a charley horse
One of the more recognizable symptoms of a blood clot in the leg is a cramping pain that resembles a charley horse. When a clot forms in a major vein in the lower limbs a condition known as deep vein thrombosis, or DVT, it can trigger aching, pain and persistent cramping. These clots can develop gradually or appear without warning, particularly after extended periods of sitting, such as during a long haul flight.
The stakes for ignoring this symptom are high. Leaving a leg clot untreated even briefly can allow it to progress into a pulmonary embolism, which occurs when a piece of the clot breaks off and travels to the lungs. Approximately one in three people with DVT will develop this potentially life-threatening complication.
Back pain without a clear cause
Back pain is rarely the first thing that comes to mind in connection with blood clots, but it can signal a clot in the pelvic region or in the inferior vena cava, the major vein running through the abdomen. Between 2.6% and 4% of people diagnosed with DVT have a clot in this location. While less common than other symptoms, these clots carry serious consequences, including permanent damage to the extremities if blood flow is cut off long enough.
Discolored skin on one limb
A disruption in normal blood flow caused by a clot can show up on the surface of the skin. If one leg develops redness or takes on an unusual color compared to the other, a blood clot is a possible explanation. The Centers for Disease Control and Prevention recommends having any such discoloration evaluated by a doctor promptly.
Skin that is warm to the touch
Along with discoloration, a localized change in skin temperature is another signal that blood flow may be compromised. A patch of skin that feels noticeably warmer than the surrounding area particularly in the leg warrants attention, especially in people who already carry known risk factors for clotting. These three symptoms, warmth, cramping and skin color changes, often appear together.
Unexplained swelling in the limbs
Sudden swelling in the arm, hand, foot, ankle or leg is among the most frequently reported symptoms of a blood clot, according to the CDC. While swelling has many possible causes, its appearance without a clear explanation is reason enough to seek medical evaluation.
Excessive sweating paired with other symptoms
On its own, sweating is rarely alarming. But when it appears alongside other warning signs, it may indicate a clot in the lung or heart two of the most medically urgent locations. In either case, the situation calls for immediate emergency care.
Shortness of breath or chest pain
A pulmonary embolism can produce shortness of breath, chest pain, difficulty breathing and, in more severe cases, a sudden drop in blood pressure, loss of consciousness or coughing up blood. Back pain, though less commonly associated with the lungs, can also accompany this type of clot. These symptoms together represent a medical emergency and require a call to 911.
Who is most at risk
Beyond prolonged sitting, other factors that raise the likelihood of DVT and clot formation include bone fractures, major surgery, chronic heart or lung disease, extended bed rest, pregnancy and the use of hormonal contraceptives. Anyone experiencing a combination of the above symptoms particularly those with known risk factors should consult a physician without delay.
