Raynaud’s syndrome is where digits turn cold, white and numb transiently, usually triggered by the cold but more particularly by cold, wet weather. Can be painful and disabling.

Prevention mostly, calcium channel blockers can be tried.

Differentiate from acrocyanosis (sluggish peripheral circulation, asymptomatic, common in young children), chilblains, vibration white finger, perniosis.

Investigations if unusually severe and/or atypical may include:

• Full blood count
• ANA, rheumatoid factor, antiphospholipid antibodies
• Complement levels
• Protein electrophoresis
• Cold agglutinins and, in children, cryoglobulins.