What is livedo reticularis?
Livedo reticularis refers to a condition in which there is mottled discolouration of the skin. It is described as being reticular (net-like, lace-like) and cyanotic (reddish blue discolouration). The discolouration surrounds pale central skin. Livedo reticularis occurs mostly on the legs but can extend to arms and trunk. It is more pronounced in cold weather.
There are several patterns.
Classification of livedo reticularis
Livedo reticularis is due to altered flow in small blood vessels feeding the upper skin so that other vessels dilate to compensate. This can arise for a variety of reasons.
Cutis marmorata causes temporary or physiological livedo in about 50% of normal infants and many adults when exposed to the cold. It is more intense and persistent in conditions associated with debility and other factors that cause stasis of deoxygenated blood where the blood vessels anastomose (join). The mottling is diffuse, mild and usually symptomless. The livedo gradually resolves on rewarming.
Cutis marmorata telangiectatica congenita
Cutis marmorata telangiectatica congenita is a rare condition in which the livedo is present at birth or soon after. There may be other congenital abnormalities including neurological and intellectual problems, and it can be familial. The livedo is usually pronounced, but it often improves with age.
Primary livedo reticularis
Primary or idiopathic livedo reticularis is livedo of unknown cause. It occurs most commonly in young and middle-aged females, particularly during winter. Mottling occurs first only on exposure to cold, but can become permanent. Tingling and numbness on cold exposure are common. Sometimes swelling, and rarely ulcers may develop in winter.
Livedo racemosa is more generalised and persistent than other forms of livedo reticularis, often affecting trunk and buttocks as well as legs. The net-like violaceous pattern tends to be composed of irregular, broken macules with an annular pattern.
Secondary livedo reticularis
Secondary livedo reticularis, and especially livedo racemosa, may be a sign of obstruction of the vessel (vasculopathy) or vasculitis (inflammation of the blood vessels). The following conditions may be responsible:
- Thrombosis due to antiphospholipid syndrome (blood clots due to sticky platelets) or lupus anticoagulant syndrome. Patients prevent with arterial events in the brain (stroke, migraine, epilepsy), eye (blindness) and heart (vascular or valve abnormalities)
- Sneddon syndrome, in which livedo racemosa is associated with stroke in young adult women
- Livedoid vasculopathy
- Cryoglobulinaemia (immune globulins that precipitate in the cold)
- Cholesterol or septic emboli
- Hypercalcaemia (calcium deposits)
- Polycythaemia rubra vera (excessive number of red cells) or thrombocythaemia (platelet clumps)
- Infections (particularly syphilis and tuberculosis)
- Arteriosclerosis (cholesterol emboli) and homocystinuria
- Thromboangiitis obliterans (Buerger disease)
- Intra-arterial injection (especially in drug addicts)
- Livedoid vasculitis
- Polyarteritis nodosa
- Systemic lupus erythematosus
- Rheumatoid arthritis
Adverse reaction to medication
- Amantadine, is a dopamine agonist used to treat Parkinson disease. Livedo is thought to be caused by depletion of catecholamines.
What are the complications of livedo reticularis?
Livedo reticularis itself is relatively benign. However, thromboembolic disease due to associated conditions such as antiphospholipid syndrome may lead to serious arterial events including death of the patient.
How is livedo reticularis diagnosed?
Livedo reticularis is diagnosed by its clinical appearance. Investigations are undertaken to seek for an underlying cause (see above).
If required, it is best to take at least 2 biopsies from red/blue and white areas of the livedo, and to ask for serial sections to be performed. Even a large skin biopsy of the centre of livedo racemosa ring may be reported as normal. Early signs are of lymphocytes and histiocytes attaching to endothelial cells (lining cells of the blood vessels). The cells join with fibrin to occlude the lumen of capillaries. Other capillaries may be dilated, or replaced by scar tissue (fibrosis).
What treatments are available for livedo reticularis?
There is no treatment for livedo reticularis. Rewarming the area in idiopathic cases or treatment of the underlying cause of secondary livedo may reverse the discolouration.
Smoking cessation is essential to reduce risk of associated arterial events such as stroke.
What is the outlook for livedo reticularis?
Cutis marmorata is usually less obvious with age. Over time, in primary livedo reticularis and livedo racemosa, the vessels become permanently dilated and livedo reticularis becomes permanent regardless of the surrounding temperature.