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Synonym: Ehrmann-Sneddon syndrome
Sneddon's syndrome is a non-inflammatory arteriopathy in which livedo reticularis is associated with cerebrovascular disease. It is slowly progressive and may go undiagnosed for some time. It may be seen in patients with an autoimmune disorder - eg, antiphospholipid syndrome or systemic lupus erythematosus (SLE).
- Incidence is estimated at four cases per million population per year, but the true incidence may be higher because some patients are not diagnosed.
- Although initially thought to have a genetic aetiology (one family cluster displayed autosomal dominant inheritance), further studies have failed to demonstrate any family history in most affected patients.
- The condition develops slowly over a variable timeframe.
- Nonspecific prodromal symptoms (headache, dizziness) often precede livedo reticularis by several years and this is followed by the development of focal neurological symptoms and then progressive cognitive impairment.
- Involvement of fundi, peripheral nerves, heart, and kidneys is frequent but usually asymptomatic.
- Livedo reticularis is a bluish mottling of skin, usually on the legs, and the appearance may be aggravated by exposure to cold.
- Sneddon's syndrome has been classified as primary if there is no clear cause, or secondary where it occurs as part of an autoimmune disorder (eg, polyarteritis nodosa, SLE, antiphospholipid syndrome), or in a thrombophilic state (eg, thrombocythaemia).[4, 5]
- Other associations include hypertension, systemic ischaemia (including ischaemic heart disease), heart valve lesions and venous thrombosis.
- Antiphospholipid antibodies have been found in 80% of patients with Sneddon's syndrome.
- Neuroimaging, including MRI, histological, immunohistochemical and ultrasound evaluation may be useful for diagnosis.
- Skin biopsy specimens reveal inflammatory changes of small- to medium-sized arteries, followed by subendothelial proliferation and fibrosis.
- In patients without any prior history of thromboembolism, minimise risk factors (stop smoking and/or combined oral contraceptives, control any hypertension, and treat any hyperlipidaemia).
- Consider prophylaxis with low-dose aspirin (clopidogrel if unable to take aspirin), particularly in patients with antiphospholipid or antiprothrombin antibodies. It may be appropriate for all patients but more research is needed.
- Patients with a history of thrombosis are treated indefinitely with anticoagulation (with warfarin ± low-dose aspirin).
- Immunosuppressive agents are used in some cases chronically resistant to anticoagulation treatment.
- Some symptoms tend to resolve over a very variable time course.
- Prevention of further vascular events with anticoagulation is the key to a good prognosis.
Further reading and references
Sneddon Syndrome; Online Mendelian Inheritance in Man (OMIM)
Marinho JL, Piovesan EJ, Leite Neto MP, et al; Clinical, neurovascular and neuropathological features in Sneddon's syndrome. Arq Neuropsiquiatr. 2007 Jun65(2B):390-5.
Livedo Reticularis; DermIS (Dermatology Information System)
Sayin R, Bilgili SG, Karadag AS, et al; Sneddon syndrome associated with Protein S deficiency. Indian J Dermatol Venereol Leprol. 2012 May-Jun78(3):407. doi: 10.4103/0378-6323.95483.
Dutra LA, Braga-Neto P, Pedroso JL, et al; Sneddon's syndrome: case report and review of its relationship with antiphospholipid syndrome. Einstein (Sao Paulo). 2012 Apr-Jun10(2):230-2.
Song HB, Woo SJ, Jung CK, et al; Acute central retinal artery occlusion associated with livedoid vasculopathy: a variant of Sneddon's syndrome. Korean J Ophthalmol. 2013 Oct27(5):376-80. doi: 10.3341/kjo.2013.27.5.376. Epub 2013 Sep 10.
Lewandowska E, Wierzba-Bobrowicz T, Wagner T, et al; Sneddon's syndrome as a disorder of small arteries with endothelial cells proliferation: ultrastructural and neuroimaging study. Folia Neuropathol. 200543(4):345-54. Folia Neuropathol. 2005
Legierse CM, Canninga-Van Dijk MR, Bruijnzeel-Koomen CA, et al; Sneddon syndrome and the diagnostic value of skin biopsies - three young patients Eur J Dermatol. 2008 May-Jun18(3):322-8. Epub 2008 May 13.
Seok HH, Noh Y, Jeong EC, et al; Treatment of Refractory Lower Extremity Ulcer Associated with Sneddon's Syndrome. Arch Plast Surg. 2013 May40(3):277-80. doi: 10.5999/aps.2013.40.3.277. Epub 2013 May 16.