A blood clot is a clump of cells and proteins in the blood that slows bleeding when you're injured. It typically dissolves as the injury heals. However, if a clot doesn't dissolve or forms unnecessarily, it can obstruct or completely block a blood vessel.

Blood clots aren't always obvious. Many develop silently within the body until they cause serious problems like heart attacks, strokes, or deep vein thrombosis. The symptoms can be difficult to detect because they're easily overlooked. Early detection allows for timely intervention.

Chest pain. Sudden, sharp chest pain can indicate a blood clot that has broken loose and caused a pulmonary embolism. It can also be a sign of a clot in an artery causing a heart attack. Pain may also radiate to the arm, especially the left arm. Clots often cause pain at the site of their formation, such as the lower leg, abdomen, or below the throat.

Swelling in the lower leg or calf. Blood clots that slow or stop blood flow can cause blood to pool in the vessels, leading to swelling. Swelling in the lower leg or calf often signals deep vein thrombosis. However, clots can also form in the arm or abdomen. Even after a clot dissolves, some individuals experience lingering swelling, sometimes accompanied by pain and sores due to blood vessel damage.

Sudden, unexplained cough. A blood clot in the lungs, known as a pulmonary embolism, can cause a sudden, dry cough. In some cases, the cough may produce small amounts of blood. A cough that doesn't respond to cough syrup or lozenges may indicate a problem in the lungs, not the throat.

Skin discoloration. When a clot blocks veins in the arms or legs, the skin in those areas may appear bluish or reddish. Skin discoloration can also result from subsequent blood vessel damage. Pleural effusion can cause pale, bluish, and clammy skin. A developing clot in a deep vein can inflame the overlying skin, causing redness, itching, and warmth without a rash or hives. This usually affects only one leg, rarely both.

Sudden vision changes in one eye. Blurred vision or vision loss in one eye can be caused by a blood clot in the arteries supplying the eye. This symptom may last only a few minutes but can be a warning sign of a transient ischemic attack (TIA), also known as a mini-stroke.

Unexplained jaw pain. While chest pain is a typical sign of a blood clot, some individuals, particularly women, experience heart-related clot issues, like heart attacks, as jaw discomfort. Warning signs may include pressure or tightness around the jawline or neck.

A cold hand or foot. A blood clot blocking blood flow to a limb can reduce circulation, making one hand or foot unusually cold while the other remains normal. This difference can be subtle but should be noted, especially if accompanied by tingling or numbness.

Bao Bao (Via WebMD, Times of India)