++
++
Idiopathic livedo reticularis is a benign condition that primarily affects the extremities
Usually asymptomatic (apart from cosmetic concerns)
Produces a mottled, purplish discoloration of the skin in a "fishnet” pattern with reticulated cyanotic areas surrounding paler central cores
Consider an underlying disease when
++
++
Spasm or obstruction of perpendicular arterioles combined with pooling of blood in surrounding venous plexuses
Worsens with cold exposure
Improves with warming
Consider an underlying disease when
++
Resembles idiopathic livedo reticularis
Has a wider skin distribution (often found on trunk and buttocks as well as extremities)
Lesions are more irregular, broken, and circular
Presenting manifestation of 25% of patients with antiphospholipid antibody syndrome
Strongly associated with the subgroup that has arterial thromboses, including those with antiphospholipid antibody–positive Sneddon syndrome (livedo reticularis and cerebrovascular events)
Other underlying causes include
Vasculitides (particularly polyarteritis nodosa)
Cholesterol emboli syndrome
Thrombocythemia
Cryoglobulinemia
Cold agglutinin disease
Primary hyperoxaluria (due to vascular deposits of calcium oxalate)
Disseminated intravascular coagulation
++
Clinical
Livedo reticularis must be distinguished from erythema ab igne, a benign cutaneous disorder caused by exposure to an infrared heat source (eg, heating pad, laptop computer)
++
Protection from exposure to cold
Vasodilators seldom indicated
If ulcerations or gangrene, exclude an underlying systemic disease