Medicine – Essential Features of Raynaud’s Phenomenon

Raynaud’s phenomenon is an episodic vasospastic disorder affecting the small blood vessels of the fingers and, less commonly, the toes. Attacks are usually triggered by cold exposure or emotional stress and result from excessive constriction of the digital arteries and arterioles. The condition may occur on its own, known as primary Raynaud’s phenomenon, or as a consequence of another disorder, particularly a connective tissue disease, in which case it is termed secondary Raynaud’s phenomenon.

1. Characteristic Colour Changes

A typical episode is characterised by a sequence of colour changes in the affected digits. Initially, the fingers become white and numb because of marked vasoconstriction and reduced arterial blood flow. This may be followed by a blue or cyanotic phase, which occurs as the tissues extract oxygen from the slowly circulating blood. When the vasospasm resolves, blood flow returns and the digits become red, warm, throbbing, and sometimes painful as a result of rebound hyperaemia. Not every patient experiences all three colour phases during every attack.

2. Prevalence

Raynaud’s phenomenon is relatively common and has traditionally been estimated to affect approximately 3–10% of adults. Primary Raynaud’s phenomenon is much more common than secondary disease and often begins in younger individuals, particularly women. In primary disease, the attacks are usually symmetrical and do not normally cause permanent tissue damage.

3. Association with Connective Tissue Disease

Only a minority of people with Raynaud’s phenomenon have an underlying connective tissue disorder, but recognising secondary Raynaud’s is important because it can indicate systemic autoimmune disease. Raynaud’s phenomenon is particularly associated with systemic sclerosis, but it may also occur in systemic lupus erythematosus, Sjögren’s syndrome, mixed connective tissue disease, and inflammatory myopathies. Secondary disease is more likely when attacks begin later in life, are markedly asymmetrical, or are accompanied by digital ulcers, tissue damage, or other systemic features.

Causes

1. Idiopathic Raynaud’s Phenomenon

In many patients, no underlying disease can be identified. This is known as primary or idiopathic Raynaud’s phenomenon. The condition is usually relatively benign, and patients typically experience intermittent attacks triggered by cold or stress without persistent vascular damage.

2. Connective Tissue Disorders

A number of connective tissue diseases can produce secondary Raynaud’s phenomenon. Systemic sclerosis is particularly strongly associated, although SLE, Sjögren’s syndrome, mixed connective tissue disease, and dermatomyositis or polymyositis may also be responsible. In these conditions, structural abnormalities of the blood vessels may accompany vasospasm and increase the risk of digital ischaemia and ulceration.

3. Cervical Rib

A cervical rib or other cause of thoracic outlet compression may interfere with the vascular supply to the upper limb and produce symptoms resembling or contributing to Raynaud’s phenomenon. The symptoms may be more pronounced on one side and may occur together with other evidence of vascular or neurological compression.

4. Increased Plasma Viscosity

Disorders associated with increased blood or plasma viscosity can impair the circulation through small peripheral vessels and contribute to Raynaud-like symptoms. These conditions should be considered particularly when other haematological or systemic abnormalities are present.

5. Drugs

Several medications can aggravate peripheral vasoconstriction. β-blockers are a well-known example and may precipitate or worsen Raynaud’s symptoms in susceptible individuals. Other vasoconstrictive drugs can have similar effects, so medication history is important when evaluating a patient.

6. Vibrating Instruments

Repeated occupational exposure to vibrating tools or machinery can damage the digital circulation and nerves, producing secondary Raynaud’s phenomenon. This is sometimes called hand–arm vibration syndrome and is classically associated with prolonged use of equipment such as pneumatic drills or other high-vibration instruments.

Treatment

1. Maintaining Warmth

The first step in management is to keep the body and extremities warm and reduce exposure to sudden temperature changes. Gloves, warm clothing, and avoidance of prolonged cold exposure can reduce the frequency and severity of attacks. During an episode, gently warming the hands may help restore circulation.

2. Avoiding Smoking and Vasoconstrictive Drugs

Patients should avoid smoking, as nicotine causes peripheral vasoconstriction and can significantly worsen symptoms. Where clinically appropriate, medications that aggravate vasospasm, including some β-blockers, should also be reviewed and avoided or replaced.

3. Calcium Channel Blockers

When conservative measures are insufficient, calcium channel blockers are commonly used as first-line pharmacological treatment. Drugs such as nifedipine relax vascular smooth muscle and reduce vasospasm, thereby decreasing the frequency and severity of Raynaud’s attacks.

4. Glyceryl Trinitrate

Glyceryl trinitrate (GTN) may be used, particularly as a topical preparation, to promote vasodilatation in affected digits. It can improve local blood flow but may cause adverse effects such as headache or dizziness because of systemic vasodilatation.

5. Prostacyclin Therapy

In severe secondary Raynaud’s phenomenon, particularly when there is critical digital ischaemia or ulceration, intravenous prostacyclin analogues such as iloprost may be used. These drugs produce potent vasodilatation and inhibit platelet aggregation, helping to improve blood flow and reduce the risk of further tissue damage.

Key Clinical Concept

Raynaud’s phenomenon is best recognised by episodic digital vasospasm producing pallor, cyanosis, and subsequent painful redness on reperfusion. Most cases are primary and relatively benign, but secondary Raynaud’s should be considered when symptoms are severe, asymmetrical, associated with digital tissue injury, or accompanied by features of a connective tissue disease.