• Clinical science

Raynaud phenomenon


Raynaud phenomenon (RP) is an exaggerated vasoconstrictive response of the digital arteries and arterioles (e.g., in the fingers and/or toes) to cold or emotional stress. It is termed primary or secondary based on the underlying cause. The etiology of primary RP is poorly understood. Secondary RP, on the other hand, is caused by underlying systemic diseases (e.g., mixed connective tissue disease, vasculitides, hematologic abnormalities). Both types typically present with the sequential discoloration of fingers and/or toes from white (ischemia) to purplish-blue (hypoxia) to red (reactive hyperemia). Episodes of vasoconstriction usually end 15–20 minutes after the trigger is removed, and last no longer than an hour following adequate warming or stress reduction. Secondary RP may be accompanied by complications of underlying diseases and/or trophic disorders. Management involves the treatment of any underlying conditions, avoidance of situations that may trigger an attack, and calcium channel blockers (e.g., nifedipine, diltiazem). Rubefacients, or vasoactive agents, are indicated in severe cases.



  • Vasospastic attack triggered by cold or emotional stress.
  • More common in women.

Primary RP (also called Raynaud disease)

  • Idiopathic (no identifiable vascular changes)
  • Vasospasms of the digital arteries and arterioles
  • Onset usually < 30 years of age

Secondary RP (also called Raynaud syndrome)


Clinical features

  • Manifestation
    • Ischemic phase (white): exposure to trigger (e.g., cold); vasoconstriction of digital arteries and arterioles ischemia and pallor
      • Sometimes accompanied by pin-and-needles sensation, numbness, or pain
    • Hypoxic phase (blue): low oxygen supply → cyanosis
    • Hyperemic phase (red): rewarming or removal of stressor leads to recovery and reperfusion → erythema
    • Livedo reticularis might occur during attacks
  • Location
    • Most commonly affects the fingers and toes
    • Rarely the nose, ears, nipples, and lips
  • Duration: Spasms are usually reversible, typically lasting 15–20 minutes after removing the trigger, but may last for up to an hour.
Primary Raynaud phenomenon Secondary Raynaud phenomenon
Clinical picture
  • Attacks typically occur symmetrically
  • No ulcerations/necrosis
  • Attacks typically occur asymmetrically
  • Severe pain and ulcerations due to critical ischemia
  • Possibly systemic manifestations of the primary disease

An attack does not always involve all three phases; often, the hyperemic phase does not occur!Irreversible ischemia with tissue damage indicates secondary RP and requires further investigation to identify the underlying cause!



While primary RP is primarily a clinical diagnosis, additional testing is required to diagnose secondary RP; . Differentiating between the two types enables the practitioner to identify and assess the severity of any possible underlying condition.

Patient history

  • Assessment of patient history focuses on the onset of symptoms, triggers of attacks, time course, pattern of attacks, accompanying symptoms (pain, paresthesias), and impairment of everyday life.
  • See “Etiology” and “Symptoms/Clinical findings” above.

Bedside test

Nailfold capillary microscopy

  • Important means of distinguishing primary from secondary RP
    • Primary RP: normal capillaroscopic pattern
    • Secondary RP: abnormal capillaroscopic pattern.

Laboratory tests

  • All values typically normal in primary RP
  • In suspected secondary RP, analyses should focus on diagnosis of underlying diseases.


Differential diagnoses


The differential diagnoses listed here are not exhaustive.


The general approaches to primary and secondary RP are similar. However, in cases of secondary RP, the underlying condition should also be treated.

General measures

Medical therapy



  • Trophic disorders (rare in primary RP)
  • Other systemic complications of underlying disease in secondary RP


We list the most important complications. The selection is not exhaustive.