Bulging veins in arms and hands can be a cosmetic concern for some people, but they can also be a sign of a more serious underlying condition. Here are some of the common causes of bulging veins in arms and hands:

• Blood pooling: Enlarged, varicose veins can bulge out as a result of blood pooling in the vein. This happens when the one-way valves inside the veins are damaged and/or weakened from age. Instead of keeping blood flowing against gravity towards the heart, vein valves let blood leak back down into the hand.

• Exercise: If you exercise a lot, especially by lifting weights, you might see bulging veins in your hands or arms. This is because when you exercise, blood flow in the area increases, and veins also swell in warmer conditions, as the body sends blood toward the surface of the skin to cool down.

• Aging: As we age, body fat is redistributed and skin becomes thinner, making veins more prominent.

• Low body fat: If you have very little body fat, your hand veins or arm veins might bulge under the skin.

• Genetics: Large veins may run in your family.

• Superficial blood clot: You may feel or see a small bulge in a hand or wrist vein, due to injury or use of an IV.

• Phlebitis: Large veins may be due to vein swelling, or inflammation.

• Deep vein thrombosis: This is a blood clot in the deep veins of your arm. This also needs medical attention. When the deep veins are obstructed, it severely restricts drainage of the hand and arm.

If you notice sudden bulging veins in your hands or arms, it could be a symptom of a serious condition, such as a blood clot or peripheral vascular disease, and you should seek medical attention.