A few weeks ago, a patient came in after a long flight from overseas. She had noticed that one of her calves felt sore and looked puffy by the time she landed, and her husband had insisted she get it checked out. Her instinct was to wave it off — she figured she had just been sitting too long and the swelling would go away on its own.
She was right that the sitting contributed. But what she had was deep vein thrombosis — a blood clot in the deep vein of her leg. And if she had waited much longer to come in, the outcome could have been very different.
I tell that story because it is not unusual. Deep vein thrombosis, or DVT, is more common than most people realize, and it is often dismissed as something minor — a cramp, a strain, or just tired legs. My goal with this article is simple: I want you to know what to look for in your own body so you do not make the same mistake.
First, a Quick Word About DVT
DVT is a condition where a blood clot forms in one of the deep veins — most often in the leg. The clot can block or slow blood flow through that vein, causing a range of symptoms that vary from person to person. Some people feel significant pain and swelling. Others notice almost nothing.
That is what makes DVT so deceptive. You may not feel sick, and the signs can be easy to explain away. But left undetected and untreated, DVT can become life-threatening — particularly if the clot breaks loose and travels to the lungs.
(For a deeper look at causes, risk factors, and how DVT develops, see our article on 7 Unique Facts About Deep Vein Thrombosis )
The 7 Signs to Watch For
1. Swelling in One Leg — Not Both
This is one of the most telling signs, and one of the most important to understand. DVT almost always affects a single leg, not both. When a clot forms in a deep vein, blood backs up behind it and fluid leaks into the surrounding tissue. The result is a leg that looks noticeably puffier than the other — around the calf, the ankle, or even the entire lower leg.
If you notice that one leg is swollen and the other looks perfectly normal, do not brush it off. Bilateral swelling — both legs — is usually related to something else. But one-sided swelling is a flag worth paying attention to.
Call your doctor today. Do not wait.
2. Calf Pain or Tenderness
The discomfort from a DVT clot can feel a lot like a muscle cramp or a pulled muscle — a dull ache, a tightness, or a soreness that gets worse when you walk or stand. Some people describe it as a heaviness rather than a sharp pain.
One thing I often ask patients to try: flex your foot upward toward your shin and see if that movement makes the pain worse. Worsening pain with this motion can be a sign of irritation along the vein — though I want to be clear that this test alone is not conclusive. It is just one clue among several.
The level of discomfort varies. Some people with DVT have significant pain that stops them in their tracks. Others have a mild soreness they might rate a two or three out of ten. Either way, calf pain in combination with any of the other signs on this list deserves a same-day call to your doctor.
Call your doctor today. Do not wait.
3. One Leg Feels Noticeably Warmer Than the Other
This is a subtler sign that many people miss entirely — but it is worth knowing about. The inflammation that forms around a blood clot generates heat, and that heat rises to the skin’s surface. Some patients notice it themselves when they run a hand down each leg and feel a clear temperature difference between the two.
It can be easy to miss if you are not specifically looking for it, and on its own it might not mean much. But combined with swelling or tenderness in the same leg, a warmth difference is an important piece of the puzzle.
Call your doctor today. Do not wait.
4. Red, Bluish, or Discolored Skin
Inflammation from a clot can cause the skin over the affected area to look flushed or red. In more significant cases — when blood is backing up more severely — you may notice a bluish or purplish tinge to the skin, which tells me that venous congestion is meaningful. You might also see the surrounding veins become more prominent or visibly darker beneath the skin.
These color changes are not always dramatic. Sometimes it is just a faint redness that looks like irritation. But any unexplained discoloration in one leg, especially alongside other symptoms, is worth having evaluated promptly.
Call your doctor today. Do not wait.
5. Prominent or Newly Visible Surface Veins
This one surprises a lot of patients. When a deep vein becomes blocked, the body reroutes blood through the surface veins as a workaround. Those veins then swell under the increased pressure and become more visible.
The key word here is new. If you have had visible veins in your legs for years, that is a different story. What I am describing is a change — veins that were not visible before suddenly becoming prominent in one leg, particularly alongside other symptoms like swelling or warmth. That kind of change deserves a call.
Call your doctor today. Do not wait.
6. Racing Heart or Shortness of Breath — Call 911
This is where I have to be direct with you, because this is no longer about a doctor’s appointment — this is an emergency.
One of the most serious complications of DVT is a pulmonary embolism, or PE. This happens when a clot breaks loose from the vein and travels up through the bloodstream to the lungs. A racing or irregular heartbeat, sudden difficulty breathing, or chest pain — especially if they appear alongside any of the leg symptoms above — are warning signs of a PE.
Do not drive yourself to the ER. Do not wait to see if it passes. Call 911 immediately.
7. Unexplained Cough or Chest Discomfort — Call 911
A dry, persistent cough with no cold or respiratory infection to explain it — particularly when it comes alongside any of the other symptoms I have described — can also signal that a clot has reached the lungs. In more severe cases, someone experiencing a PE may cough up blood.
If this is happening to you or someone you love, call 911 right now. This is a life-threatening emergency.
Who Is Most at Risk
While DVT can affect anyone, certain factors raise the likelihood. These include:
- Extended periods of immobility — long flights, car trips, or bed rest after surgery
- Recent surgery, especially orthopedic procedures involving the hips, knees, or legs
- A personal or family history of blood clots
- Cancer or certain medications, including some hormonal therapies and birth control
- Pregnancy and the postpartum period
If any of these apply to you and you are experiencing the symptoms above, I want to hear from you sooner rather than later.
When to Come See Us
Here is what I tell my patients: if something feels off — if one leg looks different, feels different, or is more tender than usual — trust that instinct and pick up the phone. DVT is one of those conditions where early detection makes a real difference in outcomes.
At Coastal Vascular Center, we can perform an in-office duplex ultrasound — a non-invasive imaging test — to either confirm or rule out DVT quickly and accurately. You do not have to guess or wait and wonder.
Signs 1 through 5 on this list: call us today. We will get you in and get you answers.
Signs 6 and 7: call 911 or go directly to the emergency room. Then follow up with us afterward so we can put a care plan in place.
Coastal Vascular Center serves patients at two convenient Texas locations:
- Pearland, TX
- Lake Jackson, TX
Call us today: (713) 999-6056 or book an appointment online
