What investigations are necessary to assess for underlying conditions in patients with Raynaud's phenomenon?

To assess for underlying conditions in patients presenting with Raynaud's phenomenon, a targeted clinical and laboratory evaluation is necessary to distinguish primary from secondary causes, particularly connective tissue diseases.

Initial investigations should include:

• Detailed clinical history and examination focusing on features suggestive of secondary Raynaud's, such as digital ulcers, severe or frequent episodes, and signs of connective tissue disease NICE CKS.
• Blood tests including antinuclear antibodies (ANA) to screen for autoimmune connective tissue diseases, rheumatoid factor, and anti-cyclic citrullinated peptide (anti-CCP) antibodies to evaluate for rheumatoid arthritis NICE CKS,NICE NG100.
• Additional serological tests may include extractable nuclear antigen antibodies (e.g., anti-Scl-70, anti-centromere) to identify systemic sclerosis and other specific autoimmune conditions Devgire & Hughes 2019.
• Inflammatory markers such as erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) to detect systemic inflammation NICE CKS.
• Capillaroscopy (nailfold capillaroscopy) is recommended in specialist settings to detect microvascular abnormalities characteristic of secondary Raynaud's phenomenon Lis-Święty 2019Devgire & Hughes 2019.
• In cases with digital ischemia or ulceration, vascular imaging such as Doppler ultrasound may be warranted to assess for proximal large vessel occlusive disease NICE CKS.

Additional considerations: In children or young patients, referral to paediatric rheumatology is advised due to the higher likelihood of secondary causes and the need for specialist assessment NICE CKS[Rigante et al. 2017].

Overall, the UK guidelines emphasise early identification of secondary causes through clinical assessment and serological testing, with specialist referral for further investigations and management as needed NICE CKS. Recent literature supports these recommendations and highlights the utility of capillaroscopy and specific autoantibody panels to improve diagnostic accuracy Lis-Święty 2019Devgire & Hughes 2019.