Raynaud Syndrome: Causes of Reduced Blood Flow to the Fingers

Raynaud Syndrome: Causes of Reduced Blood Flow to the Fingers
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Raynaud syndrome is manifested by episodes of reduced blood flow to end arterioles, most commonly the fingers and toes. The condition may indicate a more serious health problem, but not necessarily.


Raynaud syndrome is one of the vasoneuroses, a functional disorder of blood vessels. The problem is based on spasmic and temporary reduction of blood flow to the end parts of the body, primarily the fingers and toes.

Vasoneurosis = a functional disorder of blood vessels, when no organic injury is present.

Raynaud syndrome is one of the most common vasoneuroses.

The disease was first described by the French physician Maurice Auguste Gabriel Raynaud in 1862. Over the years, the condition has been associated with workload and using vibrating tools.

Raynaud syndrome = Raynaud's phenomenon =
Raynaud's disease.

In the field of the disease, two forms are mentioned, which differ from each other in several properties.

Raynaud syndrome is divided into two forms: 

  1. primary - spontaneous, of unknown cause, and unrelated to another disease
  2. secondary - as a result of another condition

Blood vessels supply blood to the body's cells, tissues, organs, and organ systems. Oxygen and various nutrients that are necessary for the body's metabolism are transported in the blood. Waste metabolism is also produced during metabolism and is toxic, so it must be eliminated from the body.

The blood-carrying vessels are the arteries, which carry blood from the heart, and the veins. The veins carry the blood towards the heart. We also know about a system of the smallest vessels in which metabolism takes place, called capillaries.

Capillaries = covering an area of about 6000 m2.

The condition in this syndrome mainly affects small and small blood vessels. Thus, the microcirculation is disrupted.

Primary Raynaud syndrome

This form occurs more common.
It is reported to represent 60-90% of cases (80% as an average).
It mostly affects women between the ages of 15 and 40.

It is a benign, i.e. less serious, harmless disease that has a functional cause. In this case, the vessels are not damaged and have a normal structure.

The syndrome is characterized by recurring episodes of reduced blood flow to certain tissues of the body. The basic mechanism is the contraction of small blood vessels and the disruption of microcirculation.

This will cause a temporary blood supply insufficiency, causing the disease's typical course.

Why this happens has not been precisely explained yet.

The difference between the primary and the secondary form is that the vessels have a normal structure and the disease does not cause critical insufficiency, i.e. either tissue ischemia or cell death, or a gangrene.

Secondary Raynaud Syndrome

The secondary form of the disease is directly related to another disease, and Raynaud's syndrome is actually a manifestation.

There is also organic vascular damage in the affected area.

In diagnostics, this distinction between the primary and secondary forms is highly significant, as secondary forms require different treatment and solution to the primary problem.

Skoré odhalenie a včasná liečba má zabrániť závažným komplikáciám, odumretiu a strate postihnutej časti. 

Although the secondary form represents about 20%, it is a sign that leads to another, often rheumatic or autoimmune disease. Also, workload and occupational diseases may be behind the condition.

The overall incidence of vasoneurosis in the population is reported to be in the range of 2 - 20% and, as already mentioned, it is most often Raynaud's syndrome and in its case the prevalence is reported to be 5-20%.

Prevalence is a statistical data, it expresses the occurrence of a given disease in a population.
It is given in relation to a certain number of inhabitants,
depending on the time period in a given place.
For example, per 100, 1000, 100 000 people population.

In the primary form, there is a higher incidence in women, including in relation to the ambient temperature.


The cause of primary Raynaud's syndrome is not clear.
What is important to know is that it is a functional disorder of the blood supply,
not an organic damage to the blood vessels.

This is why it is a multifactorial disease.

An example is the complex imbalance between vasodilation and vasoconstriction, as well as the vascular wall and vascular tone abnormalities due to neurological as well as hormonal causes.

Vasodilation = the ability of a vessel to dilate. 
Vasoconstriction = the ability of the vessel to contract.

The triggering mechanisms are the effects of cold, stress and emotions.

Hormonal action adds an increased incidence in women. Women are reported to be affected up to 7 times more often than men's. The syndrome can appear in girls of post-pubertal age, mostly after the age of 20.

The remission of problems occurs after menopause.

On the other hand, in the case of the secondary form...

The secondary form of the disease is characterized by the presence of another disease. It can often be present as a manifestation of a more serious illness.

Examples of disease characterized by Raynaud's syndrome:

Risk factors include:

  • sex - women are affected more frequently
  • age - from the age of 15 through the age of 30 to the age of 40, also due to the hormonal effect
  • ambient temperature - more often in cold areas
  • genetic predisposition and possible familial occurrence
  • smoking
  • workload, repeated vibrations, one-sided limb overload, pianists, work with a drill, jackhammer, chainsaw and the like
  • use of certain drugs and exposure to chemicals (vinyl chloride)
  • stress and persistent mental overload
  • tight clothes
  • high blood pressure
  • diabetes
  • chronic inflammation
  • high levels of fat in the blood
  • oncological diseases


The symptoms of Raynaud's syndrome are characterized by recurrence, i.e. a relapse of episodes. It is a disorder of the blood supply to the acral, or end parts of the body.

Typically, the fingers, and less commonly, the toes, are involved.

Rarely, the nose, ears, chin, nipples, or lips are affected.

The provoking factor can be cold or stress and emotional stress. Alternatively, they arise without a trigger present - spontaneously. In case of another disease by its symptom.

Typical symptoms of Raynaud's syndrome:

  • initially, pale skin of the fingers - or other part
  • blue discolouration of the affected part, such as fingers, fingertips
  • redness in the end part
  • the presence of pain in the affected area
  • tingling
  • pins and needles, burning
  • numbness in the area
  • swelling
  • in case of repeated episodes and due to other diseases, the skin may become shiny, tight

The duration of the episode can vary from just a few minutes to hours.

An episode takes about 10-20 minutes after exposure to cold, but keeping the hands warm improves and alleviates the difficulties.

Manifestations appear mostly on the upper limbs and can affect only one finger, the fingertip, several fingers, or a larger area.

In the case of the secondary form, the possibility is a worse course with the presence of complications such as a critical ischemia, i.e. a restriction in blood supply, or a restriction in blood supply, causing the characteristic ischemic pain.

The skin is affected by defects. Damage to the skin in the event of a persistent bleeding disorder alternates between cell death, or necrosis and gangrene, and sometimes the damaged part needs amputation.


In diagnosis, it is important to distinguish from the primary form of the syndrome to the secondary one. As the secondary type can also be an early sign of another disease.

First of all, we look at medical history, i.e. a personal account and information obtained from the affected person.

The following information is important:

  • frequency of alternating ischemic episodes
  • duration of the condition in minutes to hours
  • course of problems and the presence of manifestations, discolourations or pain
  • presence of other diseases already detected
  • familial incidence
  • taking any medicine
  • injury or exposure to chemicals or similar substances

This is followed by an examination of the bloodstream. The presence of pulsations and blood pressure on both limbs is monitored.

The Lewis-Prusik test is used to determine impaired peripheral circulation: pressure applied to nail bed for 6 to 10 seconds; the cold pressor test is also used(measuring changes in blood pressure).

Duplex ultrasonography is important to rule out an atherosclerotic process. Capillaroscopy is done with the aim to evaluate the condition of the small capillaries, and thus to determine whether it is the primary or secondary form.

The appearance and morphological structure of the capillaries are evaluated, most often in the area of the finger and nail bed, or in another area with the occurrence of bloodlessness.

In differential diagnosis, it is also necessary to perform laboratory blood tests, such as blood count, biochemistry, CRP, IG and others. Of course, rheumatological or neurological examinations as well as others are added to the screening process.


Raynaud's syndrome presents with typical three colour phases called the tricolour. This happens due to a change of colour of the skin, depending on the specific development of the syndrome.

However, sometimes only one or two skin changes are present (mono/bi-phase).

The tricolour syndrome is described as:

  • phase 1 - white - blanching of the skin due to vasoconstriction, the narrowing of the blood vessels
  • phase 2 - blue - cyanosis of the skin due to blood accumulation (stagnation)
  • phas 3 - red - due to re-dilation of blood vessels and sudden increase in blood flow to the skin - hyperaemia

The attack lasts for several minutes to hours. Colour changes in the skin may be accompanied by temporary pain, or vague weakness, paresthesia - tingling, pins and needles, or numbness in the affected area.

Prolonged circulatory disorder is characterized by ischemic pain, but also the risk of skin damage and the development of skin defects, ulcers and death of the bloodless part. The dead part must be surgically removed.

This complication occurs only in the secondary form.

Over time, the skin defect is necrotised, cell death occurs, and the skin becomes black = secondary Raynaud's syndrome.

The primary form is not accompanied by these complications, as the bloodstream is neither organically nor structurally damaged.

How it is treated: Raynaud Syndrome

Treatment of Raynaud's syndrome: lifestyle changes

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Interesting resources

  • "What Is Raynaud's?". NHLBI. 21 March 2014. Archived from the original on 4 October 2016. Retrieved 1 October 2016.
  • "What Are the Signs and Symptoms of Raynaud's?". NHLBI. 21 March 2014. Archived from the original on 5 October 2016. Retrieved 1 October 2016.
  • Wigley, FM; Flavahan, NA (11 August 2016). "Raynaud's Phenomenon". The New England Journal of Medicine375 (6): 556–65. doi:10.1056/nejmra1507638. PMID 27509103.
  • "Who Is at Risk for Raynaud's?". NHLBI. 21 March 2014. Archived from the original on 5 October 2016. Retrieved 1 October 2016.
  • Barker, Roger A. (2005). The A-Z of Neurological Practice: A Guide to Clinical Neurology. Cambridge University Press. p. 728. ISBN 9780521629607. Archived from the original on 24 April 2017.
  • "What Causes Raynaud's?". NHLBI. 21 March 2014. Archived from the original on 4 October 2016. Retrieved 1 October 2016.
  • Holmen OL, Backe B (2009). "An underdiagnosed cause of nipple pain presented on a camera phone". BMJ339: b2553. doi:10.1136/bmj.b2553. S2CID 71701101.
  • Pistorius MA, Planchon B, Schott JJ, Lemarec H (February 2006). "[Heredity and genetic aspects of Raynaud's disease]". Journal des Maladies Vasculaires (in French). 31 (1): 10–5. doi:10.1016/S0398-0499(06)76512-X. PMID 16609626.
  • Wigley, Fredrick M.; Flavahan, Nicholas A. (10 August 2016). "Raynaud's Phenomenon". New England Journal of Medicine375 (6): 556–565. doi:10.1056/nejmra1507638. PMID 27509103.
  • Gayraud M (January 2007). "Raynaud's phenomenon". Joint, Bone, Spine74 (1): e18. doi:10.1016/j.jbspin.2006.07.002. PMID 17218139.