Causes of thread veins

This section discusses the causes and symptoms of thread veins. Many of these causes are also responsible for varicose veins.

What we do know is that your skin becomes lined, thinner and prone to damage as we age. There is a reduction in the volume of subcutaneous fat within the skin which means that the veins (including thread veins) become much more visible. Thread veins are a common condition and as such, are not something to be worried about.

But there are people who feel less attractive as a result of them.

Reasons for thread veins

Thread veins occur for a variety of reasons which include:

  • Genetic tendency
  • Age
  • Gender
  • Varicose veins
  • Leg injuries
  • Occupation
  • Prolonged sun exposure
  • Chemotherapy/radiotherapy
  • Overweight/obese
  • Sedentary lifestyle
  • Phlebitis
  • Thrombosis
  • Medical conditions such as tumours inside the abdomen or severe liver disease
  • Rosacea

So, there are many different reasons why someone develops thread veins. Find out more about these in the sections below.

Genetic tendency

By this we mean a family history of thread veins and/or varicose veins. Thread veins are usually inherited so if your parents, grandparents or a close family member have thread veins then there is a fair chance you will do the same.

This may mean that you have inherited a tendency towards varicose veins as well. This occurs due to defective or weak valves within the veins which affect the blood circulation and cause the veins to become enlarged.

This leads to either thread veins or varicose veins.

This genetic factor plays a part where identical twins have thread veins. It is not unusual for both twins to develop these and in the same area of the body. If this occurs then it is usually inherited.

People say choose your parents carefully and this certainly applies in this case. But a family history does not mean that you will automatically develop thread veins; just that you have a higher than normal chance of doing so.


The ageing process is a major cause of thread veins and not something that you can do too much about. Your veins start to show signs of wear and tear as you grow older and this leads to conditions such as thread veins and varicose veins.

But thread veins can occur in younger people. It is not uncommon for someone in their twenties to develop these although this tends to be fairly rare.

The normal trend is for thread veins to appear in middle age and older.


Like varicose veins, thread veins are more likely to occur in women than men for several reasons.

One of these is pregnancy in which the uterus puts a strain on the veins in the pelvic area as a result of having to accommodate the growing baby.

The risk of thread veins and varicose veins is greater in women who have undergone several pregnancies compared to women who have never had children.

Thread veins tend to appear during pregnancy but usually disappear after childbirth.

Fluctuations in hormones such as oestrogen are another factor. These fluctuations occur during puberty, pregnancy and the menopause and cause a variety of effects in the body. One of these is the development of thread veins.

Female hormones have a relaxing effect on the walls of the veins which causes them to become weaker and prone to damage, e.g. thread veins.

This is also a problem with oral contraceptives. These contain synthetic versions of the female hormones oestrogen and progesterone and are designed to prevent an unwanted pregnancy.

But they have the same effect in that they too relax the walls of the veins which mean an increased risk of varicose and thread veins.

Varicose veins

This is a condition in which the veins become damaged to a variety of reasons which prevents them from pumping blood up towards the heart. Blood then collects in the lower area of the body, e.g. the legs which put pressure on the veins.

The veins become enlarged and distorted, taking on that familiar knotted appearance.

Many people who develop varicose veins also get thread veins but this is not automatic. It is possible to develop thread veins without getting varicose veins and vice versa.

Leg injuries

An injury such as a fracture can also affect the veins. This damage often affects the blood circulation which then increases the risk of conditions such as these.

Plus there is also the fact that many fracture patients are less mobile than usual. This inactivity means that blood is not being circulated around the body which can cause problems. Blood pools in the lower half of the body, e.g. the legs which then puts pressure on the veins.


Certain types of jobs which require a person to be stood on their feet for a long period of time can result in thread veins. Doing this means that the circulation slows down which results in blood collecting in the lower part of the body.

The veins dilate and weaken. This can lead to varicose veins as well as thread veins.

Prolonged sun exposure

Spending long periods of time in the sun can result in thread veins. This is especially the case in regard to facial thread veins which occur due following an increase in blood flow through the capillaries.

Sunburn, applying hot water to your face and sunbathing are all potential triggers for thread veins. This is a greater problem for fair skinned people.


These are both very effective treatments for cancer but one of their side effects is the development of thread veins. This may be due to the radiation emitted during this treatment which can be damaging to the body as a whole.


This extra weight puts a strain on the veins which weakens them over time. This weakness leads to poorly functioning valves which interferes with their ability to pump blood around the body.

The end result is thread veins. Another problem is varicose veins.

Sedentary lifestyle

Standing on your feet for a long period of time is not advisable but neither is sitting down for hours upon end. This is further compounded by crossing the legs at the ankles which constricts the circulation.

Long periods of inactivity should be broken up with short breaks, e.g. getting up and walking around.


This is the medical name for inflammation of the wall of the vein. This is often accompanied by thrombosis – formation of a blood clot in the vein, and both of these prevent blood from circulating as normal.

The affected vein hardens and becomes swollen and painful which leads to conditions such as thread veins.


This is where a blood clot forms within a vein which then restricts blood flow through that vein. If a piece of this blood clot breaks off and then travels through the vein up towards the lungs then there is a risk of pulmonary embolism (blockage in the lungs).

Medical conditions

There are conditions such as abdominal tumours or severe liver disease which can cause thread veins to develop. These can obstruct the normal flow of blood through the veins and to and from the heart.

Any interruption such as a blockage can put pressure on the veins, causing them to weaken and fail to work properly. This often results in vascular conditions such as varicose veins or thread veins.

And finally…


This is a skin condition which usually affects middle aged women and especially those with a fair skinned complexion.

Tiny blood vessels in the cheeks, nose and other areas of the face become infused with blood and expand and as a result of this. This causes the veins to become prominent on the surface of the skin and may be accompanied by a small cluster of acne.

The face takes on a reddened, flushed appearance and is accompanied by thread veins. This causes a great deal of distress to the sufferer.

Rosacea is triggered by certain foods, e.g. spicy foods, caffeine, alcohol and changes in temperature, e.g. moving from a cold to a hot environment.

Thread veins also develop in people who work outdoors or have used certain skin care products such as steroid creams.

Symptoms of thread veins

The most obvious sign is that of a visible network of red or bluish veins which look similar to tree branches and are located near the surface of the skin.

These veins do not cause any pain or discomfort, but, they cause a great deal of embarrassment and upset to the sufferer. Some people are unconcerned by this but others find that they are a source of anxiety and distress.

If you are in the latter group then have a look at the various treatments on offer. Find out more in our treatments for thread veins section.

Guide to Thread Veins

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