Why do some people have blue veins on their hands? Be careful if you have blue veins in these places

Have you ever noticed this phenomenon: some people's hands look smooth and delicate, while some people have abnormally prominent "blue veins" on the back of their hands.

Regarding blue veins, there are often rumors online that blue veins on the arms indicate problems with internal organs, stagnation in the body... After reading them, people can't help but worry whether there is something wrong with their body, but in most cases, blue veins on the skin are normal and healthy.

So, why do some people have very obvious protrusions of blue veins? Which abnormal protrusions of blue veins need to be paid attention to? Let's talk about it today.

What exactly are the so-called “blue veins”?

Blue veins are actually the veins under our skin . Their main task is to transport blood from various parts of the body back to the heart. Compared with arteries, veins have thinner walls and are located more shallowly, which makes them easier to observe.

But why do these veins appear blue, rather than red, just beneath the skin?

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This is mainly related to the penetration depth of light, reflection characteristics and the color perception mechanism of the human eye .

Blue light penetrates the skin less deeply than red light, so the reflection of blue light is less affected by the depth of blood vessels, while red light penetrates deeper and is absorbed by deoxyhemoglobin, reducing the reflection more. This difference in reflection makes veins look blue, and blue and a small amount of green appear cyan.

Figure 1. Simulated intensity changes of short wavelength (450 nm, blue light), medium wavelength (550 nm, green light), and long wavelength (633 nm, red light) reflected from the vein area after passing through the skin.

According to the Retinex theory, the human eye perceives color by comparing the ratio of light reflected from blood vessel areas to that from surrounding tissue. Since the reflection of red light is reduced more significantly, the human eye ultimately perceives veins as cyan.

Figure 2 The difference in light reflection intensity between the vein area and the surrounding area at different wavelengths

The depth and diameter of the veins also have an impact: deeper and larger vessels enhance this blue perception.

In short, the blue color of veins is the result of the combined effect of optical properties and visual perception.

Why do some people have bulging veins?

Very obvious?

In our daily life, we can easily find that some people can see particularly obvious blue veins on the back of their hands and arms, while others can hardly see any trace of blood vessels. This difference is related to many factors in the body.

1

Body fat thickness

If a person has less subcutaneous fat, such as a thin person or someone who exercises regularly, the veins will be easier to see, especially after exercise, when blood circulation speeds up, venous blood flow increases, and the blood vessels will bulge out significantly in a short period of time. For those with thicker subcutaneous fat, the fat layer acts like a "partition" that makes the veins less visible.

2

age

Young people have good skin elasticity, firmness and thickness, so even if the blood vessels are slightly protruding, they are not noticeable. However, as we age, the skin gradually becomes loose and thinner, and the veins lose their cover and become more prominent. This is why older people are more likely to be troubled by "blue veins".

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As for which one is healthier, it is impossible to judge simply by looking at the "number of blue veins". It still needs to be judged in combination with the overall physical condition.

Pay attention to these types of abnormal bulges of blue veins

In most cases, the appearance of blue veins is a normal physiological phenomenon and we don’t need to worry. However, some of them may be a signal for help from the body. We can judge whether there are potential health problems in time according to the location, shape and accompanying symptoms of the blue veins.

1

Lower limb vein bulge

If you find that the veins in your lower limbs are bulging , especially after standing or sitting for a long time, the veins in your legs are particularly obvious, and each section is uneven in thickness, or even accompanied by soreness or fatigue, it may be a sign of varicose veins . You should see a vascular surgeon as soon as possible to rule out chronic venous disease. If it is not improved for a long time, it may lead to lower limb edema, ulcers, or even thrombosis.

2

Local blue veins appear

Another thing to watch out for is the appearance of local blue veins after sudden pain, swelling or skin fever in the lower limbs, especially if it only occurs on one side. This may be a manifestation of acute deep vein thrombosis ; or if blue veins reappear on the lower limb 6 months after sudden pain, swelling or skin fever on one side , accompanied by heaviness, distending pain, itchy skin, pigmentation, eczema, etc., the possibility of chronic deep vein thrombosis should be considered. Some people may even have bulging blue veins in the abdomen at this time. These symptoms should be treated by vascular surgery as soon as possible.

3

Bulging veins on the abdomen

However, if the blue veins in the abdomen are bulging, the more common cause is compression of the two major venous systems, the portal vein and the inferior vena cava, which is common in conditions such as cirrhosis, ascites, and inferior vena cava thrombosis .

4

The blue veins in the neck continue to show

In addition, the sudden and persistent appearance of blue veins in the neck may be related to right heart failure and superior vena cava syndrome . The former is usually accompanied by lower limb edema and dyspnea, while the latter is usually accompanied by upper limb and facial edema.

In general, if you find abnormally raised veins accompanied by pain, swelling, skin changes, etc., you should see a doctor as soon as possible to avoid delaying treatment. Healthy veins are "quiet", and any "unquiet" performance is worthy of vigilance.

References

[1]Kienle A, Lilge L, Vitkin IA, et al. Why do veins appear blue? A new look at an old question. Appl Opt. 1996;35(7):1151.

[2]Bradbury A, Evans C, Allan P, et al. What are the symptoms of varicose veins? Edinburgh vein study cross sectional population survey. BMJ. 1999;318(7180):353-6.

[3]Kumar P, Khan IA, Das A, et al. Chronic venous disease. Part 1: pathophysiology and clinical features. Clin Exp Dermatol. 2022;47(7):1228-1239.

[4] Vascular Surgery Group, Chinese Medical Association, Surgery Branch. Guidelines for the diagnosis and treatment of deep vein thrombosis (3rd edition). Chinese Journal of General Surgery, 2017, 32(9): 807-812.

[5]Norys JH, Sexton KW, Jensen HK, et al. Deep vein thrombosis causing abdominal wall varicosities. J Surg Case Rep. 2023;2023(2):rjad004.

[6] Ge Junbo, Wang Chen, Wang Jianan. Internal Medicine (10th edition). Beijing: People's Medical Publishing House. 2024.

[7]Mehrzad R. Abdominal varicosities secondary to inferior vena cava filter thrombosis. BMJ Case Rep. 2015;2015:bcr2015209479.

[8]Trivedi SB, Ray C, Chadalavada S, et al. Superior Vena Cava Syndrome: An Update and Literature Review of Percutaneous Endovascular Treatments. Semin Intervent Radiol. 2022;39(4):446-453.

Planning and production

Author: Jiang Yongyuan, Master of Internal Medicine, Third Military Medical University

Reviewer: Huang Panbing, Director of Internal Medicine, People's Hospital of Suxitong Science and Technology Industrial Park, Nantong, Jiangsu

Planning丨Wang Mengru

Editor: Wang Mengru

Proofread by Xu Lailinlin