A DVT usually forms in the veins of your legs or arms. Up to 30%of people with a DVT don’t have symptoms, but sometimes the symptoms are very mild and may not raise concern. The symptoms associated with an acute DVT include: Swelling of your leg or arm (sometimes this happens suddenly). Pain or tenderness in your leg or arm (may only happen when standing or walking). The area of your leg or arm that’s swollen or hurts may be warmer than usual. Skin that’s red or discolored. The veins near your skin’s surface may be larger than normal. Abdominal pain or flank pain (when blood clots affect the veins deep inside your abdomen). Severe headache (usually of sudden onset) and/or seizures (when blood clots affect the veins of your brain). Some people don’t know they have a DVT until the clot moves from their leg or arm and travels to their lung. Symptoms of acute PE include chest pain, shortness of breath, cough with blood, lightheadedness and fainting. It’s important to call your doctor right away or go to the emergency room if you have symptoms of a DVT. Don’t wait to see if your symptoms go away. Get treatment right away to prevent serious complications.