Although, other studies also reveal that CCBs may be effective at decreasing severity of attacks, pain and disability associated with Raynauds phenomenon. People whose disease is secondary to erythromelalgia often cannot use vasodilators for therapy, as they trigger flares causing the extremities to become burning red due to too much blood supply. People with severe disease prone to ulceration or large artery thrombotic events may be prescribed aspirin. Sympatholytic agents, such as the alpha-adrenergic blocker prazosin, may provide temporary relief to secondary Raynauds phenomenon. Losartan can, and topical nitrates may, reduce the severity and frequency of attacks, and the phosphodiesterase inhibitors sildenafil and tadalafil may reduce their severity. Angiotensin receptor blockers or ACE inhibitors may aid blood flow to the fingers, and some evidence shows that angiotensin receptor blockers (often losartan) reduce frequency and severity of attacks, and possibly better than nifedipine. The prostaglandin iloprost is used to manage critical ischemia and pulmonary hypertension in Raynauds phenomenon, and the endothelin receptor antagonist bosentan is used to manage severe pulmonary hypertension and prevent finger ulcers in scleroderma. Statins have a protective effect on blood vessels, and SSRIs such as fluoxetine may help symptoms, but the data is weak. PDE5 inhibitors are used off-label to treat severe ischemia and ulcers in fingers and toes for people with secondary Raynauds phenomenon; as of 2016, their role more generally in Raynauds was not clear. Surgery
In severe cases, an endoscopic thoracic sympathectomy  procedure can be performed.
Primary Raynauds is thought to be at least partly hereditary, although specific genes have not yet been identified.Smoking increases frequency and intensity of attacks, and a hormonal component exists. Caffeine, estrogen, and nonselective beta-blockers are often listed as aggravating factors, but evidence that they should be avoided is not solid. Secondary
Raynauds phenomenon, or secondary Raynauds, occurs secondary to a wide variety of other conditions. Secondary Raynauds has a number of associations:
Connective tissue disorders:
Scleroderma
Systemic lupus erythematosus
Rheumatoid arthritis
Sjögrens syndrome
Dermatomyositis
Polymyositis
Mixed connective tissue disease
Cold agglutinin disease
Ehlers-Danlos syndrome
Eating disorders:
Anorexia nervosa
Obstructive disorders:
Atherosclerosis
Buergers disease
Takayasus arteritis
Subclavian aneurysms
Thoracic outlet syndrome
Drugs:
Beta-blockers
Cytotoxic drugs – particularly chemotherapeutics and most especially bleomycin
Cyclosporin
Bromocriptine
Ergotamine
Sulfasalazine
Anthrax vaccines whose primary ingredient is the Anthrax Protective Antigen
Stimulant medications, such as those used to treat ADHD (amphetamine and methylphenidate)
OTC pseudoephedrine medications (Chlor-Trimeton, Sudafed, others)
Occupation:
Jobs involving vibration, particularly drilling and prolonged use of a string trimmer (weed whacker), experience vibration white finger
Exposure to vinyl chloride, mercury
Exposure to the cold (e.g., by working as a frozen food packer)
Others:
Physical trauma to the extremities
Lyme disease
Hypothyroidism
Cryoglobulinemia
Cancer
Chronic fatigue syndrome
Reflex sympathetic dystrophy
Carpal tunnel syndrome
Magnesium deficiency
Multiple sclerosis
Erythromelalgia (clinically presenting as the opposite of Raynauds, with hot and warm extremities, often co-exists in patients with Raynauds)
Chilblains (also clinically presenting as the opposite of Raynauds, with hot and itchy extremities, however it affects smaller areas than erythromelalgia, for instance the tip of a toe rather than the whole foot)Raynauds can precede these other diseases by many years, making it the first presenting symptom.