Raynaud’s phenomenon is an abnormal reaction to cold exposure or sometimes in response to emotional stimuli characterized by the digits discoloration.
Raynaud’s phenomenon is a common disorder affecting about 3-5% of the population with a somewhat higher prevalence among young females. This disorder is characterized by the episodic ischemia of the digits triggered by the cold exposure and sometimes emotional stress. Usually, one or several digits are affected and hands are more likely to be involved rather than toes. Nevertheless, sometimes the ear, nose or other parts of the body may appear involved as well.
Raynaud’s phenomenon develops as an abnormal reaction of the vessels in response to cold – the arteries supplying the digits constrict (ischemic phase characterized by the white/pale discoloration of the fingers) whereas small venules and capillaries dilate causing stasis of the deoxygenated blood (the fingers become bluish), later when the hands are rewarmed and the arteries dilate blood flow is restored and even exceeds the normal resulting in so-called reactive hyperemia – digits become bright red and throbbing sensation may occur.
- Women are more likely to experience Raynaud’s phenomenon;
- Prevalence is also higher among smokers;
- Those with a family history of Raynaud’s phenomenon are also at risk;
- Emotional stress may be related to the development of Raynaud’s phenomenon;
- Administration of estrogen-containing medications was also linked to Raynaud’s phenomenon in women;
- It was suggested that men who use pneumatic hammers, chain saws, sanders, and grinders while working can eventually develop the hand-arm vibration syndrome that features Raynaud’s phenomenon;
Classification and origins
Primary (idiopathic) Raynaud’s phenomenon is a benign disorder developing in individuals with no other known conditions that may cause its occurrence.
Secondary Raynaud’s phenomenon develops a result of other conditions including:
- Connective tissue diseases such as systemic lupus erythematosus, scleroderma, rheumatoid arthritis, poy- and dermatomyositis, Sjögren’s syndrome, etc.;
- Diseases affecting arteries: atherosclerosis of the blood vessels of the limbs, acute occlusion of the arteries by the emboli, subclavian artery aneurysm, etc.;
- Pulmonary hypertension;
- Neurologic conditions: stroke, spinal cord tumors, carpal tunnel syndrome, etc.;
- Endocrine diseases: hypothyroidism;
- Disorders affecting blood: polycythemia vera, multiple myeloma, lymphoplasmacytic lymphoma, cryoglobulinemia, cryofibrinogenemia, cold agglutinins;
- Infections: hepatitis B and C;
- Occupational diseases: electric shock injury to the hands or frostbite, hand-arm vibration syndrome;
- Certain drugs such as amphetamines, cocaine, β-blockers, clonidine, ergot preparations, oral contraceptives, cyclosporine, bleomycin, vinblastine, cisplatin, gemcitabine, etc.;
- Toxins: lead and arsenic;
In case of Raynaud’s phenomenon, there are episodes when digits suffer from ischemia resulting in a consecutive color change of the fingers known as the triphasic color response: the digits turn white after cold exposure (pallor), then become bluish (cyanotic) and finally red upon warming when the arterioles dilate. During the pallor phase, there may be also a sensation of cold, numbness or other unusual sensations called paresthesias in the digits. When the blood supply to digits is restored and the fingers turn red and throbbing, painful sensation occurs.
However, in some individuals there are only one or two phases of the Raynaud’s phenomenon observed – there may be only pallor and cyanosis or even only cyanotic phase.
Diagnosis is made based on the typical appearance of the fingers, additional testing may be necessary to verify the underlying disorder in secondary Raynaud’s syndrome.
Mild cases of Raynaud’s phenomenon do not require any special treatment. The only approved measure is to avoid exposure to cold, dress warmly and wear gloves/mittens. Furthermore, smoking should be avoided as tobacco causes constriction of blood vessels and may worsen the condition or trigger attacks.
In severe cases, calcium channel antagonists such as nifedipine, isradipine, felodipine, and amlodipine are administered. Diltiazem may be used, though it is less effective. Phosphodiesterase type 5 inhibitors such as sildenafil, tadalafil, and vardenafil are helpful for the treatment of secondary Raynaud’s phenomenon.
Other treatment options include surgical intersection of the sympathetic nerves innervating the digits (digital sympathectomy). There is also an experimental treatment that implies injection of botulinum toxin in the wrist.