Livedo reticularis
Salient
features
Livedo reticularis (ILR)
is a mottled bluish (Iivid) discoloration of the skin that occurs in a net-like
pattern. It is not a diagnosis in itself but a reaction pattern.
Classification
distinguishes between:
· Idiopathic livedo reticularis
(ILR): A purple/livid discoloration of the skin in a netlike pattern
disappearing after warming. It is a physiologic phenomenon. (Synonym: cutis
marmorata).
· Secondary
(symptomatic) livedo reticularis (SLR): A purple discoloration occurring in a
starburst or lightning-like pattern, netlike but with open (not annular)
meshes; mostly, but not always, confined to the lower extremities and buttocks.
It is a reaction pattern often indicative of serious systemic disease.
(Synonym: livedo racemosa).
· Sneddon syndrome is a
potentially life-threatening disease occurring more often in women than in men
and manifesting in the skin as SLR and in the CNS as transient ischemic attacks
and cerebrovascular insults. May be associated with livedoid vasculitis with
ulcerations on ankles and acrally.
· Management: No
treatment necessary for ILR; for SLR, keep from chilling, pentoxifylline,
low-dose aspirin, and heparin.
Definition
Livedo is an ischemic dermopathy characterized by mottled,
cyanotic discoloration (lace‐like
pattern) on the surface of the skin created by low blood flow through the
cutaneous microvasculature system.
Epidemiology
Livedo reticularis is typically a primary disorder that
affects young to middle-aged females (20-50 years of age) who are otherwise
healthy. The epidemiological factors of livedo racemosa are dependent on the
underlying condition. It is the most frequent dermatological manifestation in
patients with antiphospholipid syndrome, present in 25% of patients with
primary APS and in up to 70% of patients with SLE-associated APS.
Pathogenesis
LR results from
alterations in blood flow through the cutaneous microvasculature system. The
latter consists of arterioles that are oriented perpendicularly to the skin
surface. The vessels then divide into capillary beds that in turn drain into a
subpapillary plexus. It has been proposed that this arrangement of vessels
gives rise to a series of cones,
the bases of which measure 1–4 cm in diameter and lie on the skin's
surface
with the ascending arteriole at the apex of each cone. At the edge of the cone,
the venous plexus is more prominent and the arterial bed is diminished. Any
process that reduces blood flow through
the feeding arterioles will
result in the accumulation of deoxygenated blood in the venous plexus produces a cyanotic network pattern on the skin which is
livedo reticularis. Diminished arterial flow can result from vasospasm, hyper
viscosity and/or thrombosis. Physiological arterial vasospasm produces the
reversible cutaneous discoloration of livedo reticularis. Livedo reticularis can occur as a
physiological reaction to cold exposure and disappears with warming, when it is
known as Cutis marmorata. Protracted arteriolar vasospasm, hyper viscosity
and/or thrombosis underlie the pathologic skin changes of livedo recemosa.
Livedo vasculopathy is a rare ulcerative subtype of livedo racemosa
due to fibrinolytic abnormalities and microcirculatory thrombosis.
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Clinical
features
History
With the exception of a subjective feeling of coldness, the
majority of patients with livedo reticularis are asymptomatic. Patients often
present with concerns regarding their skin discoloration. A minority describes
mild pain and numbness. The symptoms are worse during winter months. Livedo racemosa-associated
symptoms are related to the causative secondary disorder.
Cutaneous lesions
In livedo reticularis, a symmetric fishnet-like red or
purple mottling surrounds a pallorous conical core. This discoloration is
aggravated by cold exposure and may completely dissipate with warming. The
livedo rings are most pronounced on the lower limbs, but the abdomen and upper
limbs may also be affected.
In contradistinction to symmetric and uniform patter of
livedo reticularis, the discoloration of livedo racemosa is asymmetric,
irregular, and “broken”. Although it may improve with warming, it does not
resolve completely. Attendant skin manifestation of livedo racemosa may include
purpura, nodules, macules, ulcerations and/or atrophic blanch- type scarring.
When associated with livedoid vasculitis, ulceration develops. In livedoid vasculitis,
classical triad is livedo racemosa, recurrent painful small punched-out
ulcers that have a very poor tendency for healing
followed by atrophic blanch- type scars that occurs on the dorsum of forefoot,
ankles and lower legs distributed symmetrically.
In both livedo reticularis and livedo racemosa, the skin is
palpably cool.
Laboratory tests
In livedo reticularis laboratory testing is typically
negative and consequently is unwarranted. An APA panel should be obtained on
all patients presenting with livedo racemosa. Typical investigations would
include a thrombophilia screen, autoimmune screen, full blood count, metabolic
panel and serum protein electrophoresis. Further investigations such as
ultrasound and echocardiography may be required to look for sources of emboli.
A skin biopsy is not required in livedo reticularis as the
findings are nonspecific. A large punch or wedge biopsy of the deep reticular
dermis and subcutaneous fat is sometimes helpful in identifying the secondary
cause of livedo racemosa. In skin biopsies it is necessary to sample the affected
arterioles and should be performed from both the
central blanched areas and the purplish livedo areas to increase the diagnostic
yield as changes may be present in either or both areas.
Diagnosis
The
diagnosis of livedo is easily made by identifying the characteristic mottled
skin discoloration. It is paramount that the clinician distinguishes between
livedo reticularis and livedo racemosa. Once diagnosis of livedo racemosa is
established, the secondary cause should be sought by appropriate clinical
laboratory tests. Diagnostic difficulties may occur when no other pathological
signs except livedo racemosa are found. This clinical condition, known as
“idiopathic livedo racemosa”, may represent a very early stage of sneddon
syndrome.
