Doppler ultrasound to assess blood flow
Full blood count may reveal a normocytic anaemia suggesting the anaemia of chronic disease or kidney failure. Blood test for urea and electrolytes may reveal kidney impairment. Thyroid function tests may reveal hypothyroidism. Tests for rheumatoid factor, erythrocyte sedimentation rate, C-reactive protein, and autoantibody screening may reveal specific causative illnesses or an inflammatory process. Anti-centromere antibodies are common in limited systemic sclerosis (CREST syndrome). Nail fold vasculature (capillaroscopy) can be examined under a microscope.To aid in the diagnosis of Raynauds phenomenon, multiple sets of diagnostic criteria have been proposed. Table 1 below provides a summary of these various diagnostic criteria.Recently, International Consensus Criteria were developed for the diagnosis of primary Raynauds phenomenon by a panel of  experts in the fields of rheumatology and dermatology. Management
Secondary Raynauds is managed primarily by treating the underlying cause, and as primary Raynauds, avoiding triggers, such as cold, emotional and environmental stress, vibrations and repetitive motions, and avoiding smoking (including passive smoking) and sympathomimetic drugs. Medications
Medications can be helpful for moderate or severe disease. Vasodilators – calcium channel blockers, such as the dihydropyridines nifedipine or amlodipine, preferably slow-release preparations – are often first-line treatment. They have the common side effects of headache, flushing, and ankle edema, but these are not typically of sufficient severity to require cessation of treatment. The limited evidence available shows that calcium-channel blockers are only slightly effective in reducing how often the attacks happen.
Raynaud syndrome, also known as Raynauds phenomenon, eponymously named after the physician Auguste Gabriel Maurice Raynaud, who first described it in his doctoral thesis in 1862, is a medical condition in which the spasm of small arteries causes episodes of reduced blood flow to end arterioles. Typically, the fingers, and less commonly, the toes, are involved. Rarely, the nose, ears, or lips are affected. The episodes classically result in the affected part turning white and then blue. Often, numbness or pain occurs. As blood flow returns, the area turns red and burns. The episodes typically last minutes but can last several hours.Episodes are typically triggered by cold or emotional stress. Primary Raynauds, also known as idiopathic, means that it is spontaneous, of unknown cause, and unrelated to another disease. Secondary Raynauds occurs as a result of another condition and has an older age at onset; episodes are intensely painful and can be asymmetric and associated with skin lesions. Secondary Raynauds can occur due to a connective-tissue disorder such as scleroderma or lupus, injuries to the hands, prolonged vibration, smoking, thyroid problems, and certain medications, such as birth control pills. Diagnosis is typically based on the symptoms.The primary treatment is avoiding the cold. Other measures include the discontinuation of nicotine or stimulant use. Medications for treatment of cases that do not improve include calcium channel blockers and iloprost. Little evidence supports alternative medicine. Severe disease may in rare cases lead to complications, specifically skin sores or gangrene.About 4% of people have the condition.