Raynaud’s phenomenon is a condition that affects blood flow to certain areas of the body, typically the fingers and toes, in response to cold or stress. It results in episodes where the affected areas turn white or blue due to a temporary reduction in blood supply. The condition is named after the French doctor Maurice Raynaud, who first described it in the 19th century.

What happens in Raynaud’s phenomenon?
Small arteries or arterioles constrict, in fingers, toes, ears, and nose, limiting blood supply to these sites which results in the affected area becoming white, blue, or purplish, because there is reduced flow of blood. With the subsiding of an attack, blood again starts to flow, with red colouration of skin, when it re-warms and re-oxygenates. These episodes can last from a few minutes to about half an hour and usually happen in cold weather or when one is stressed.



The underlying mechanism of Raynaud’s phenomenon is vasospasm—the sudden constriction of blood vessels in response to triggers like cold temperatures or emotional stress. In normal circumstances, the blood vessels constrict and dilate in response to temperature changes, helping regulate body temperature. However, in people with Raynaud’s phenomenon, this regulation is exaggerated and dysfunctional. The body responds to cold or stress by overreacting, leading to excessive constriction of the blood vessels, thus impeding blood flow to the extremities.

The exact cause of this exaggerated response is not fully understood, but it is believed to be due to a combination of genetic, environmental, and possibly autoimmune factors.

Types of Raynaud’s phenomenon
Primary Raynaud’s phenomenon: This is the more common form of the condition and occurs without any underlying health problem. It is often triggered by cold temperatures or emotional stress. Primary Raynaud’s is typically not associated with any other disease and tends to be less severe.

Secondary Raynaud’s phenomenon (also known as Raynaud’s disease): This form is associated with other underlying health conditions, particularly autoimmune or connective tissue diseases. Secondary Raynaud’s is often more serious and can lead to permanent damage to blood vessels and tissues.

Underlying causes of Raynaud’s phenomenon
Raynaud’s phenomenon, especially in its secondary form, can be associated with several underlying conditions:

• Systemic sclerosis (Scleroderma): This condition leads to hardening and tightening of the skin and connective tissues. It can cause narrowing of blood vessels, contributing to Raynaud’s phenomenon.
• Lupus: Systemic lupus erythematosus (SLE) is an autoimmune disease that can damage blood vessels, leading to episodes of Raynaud's.
• Rheumatoid arthritis: This inflammatory condition can affect blood vessels and contribute to Raynaud’s phenomenon.
• Atherosclerosis: Plaque buildup in the arteries can reduce blood flow and trigger Raynaud’s-like symptoms.
• Buerger’s disease: This rare condition causes inflammation and clots in blood vessels, leading to restricted blood flow, especially in the hands and feet.
• Medications: Certain medications, such as beta-blockers, some chemotherapy drugs, and vasoconstrictors, can cause blood vessel constriction, contributing to Raynaud's episodes.
• Environmental factors: Prolonged exposure to cold temperatures or vibrating tools can cause repetitive injury to the blood vessels, increasing the risk of Raynaud's.
• Nerve damage: In some cases, nerve damage (such as that from a traumatic injury) can disrupt the normal function of blood vessels, leading to Raynaud’s phenomenon.
• Genetic factors: Family history may play a role, as Raynaud’s phenomenon sometimes runs in families, suggesting a genetic predisposition to the condition.