Idiopathic livedo reticularis occurs mostly in women as symmetric diffuse mottling on cold exposure, sometimes accompanied by numbness and tingling. The discoloration is persistent and may change from reddish blue in a warm environment to a deep blue in a cold environment.
Two variants of livedo reticularis with ulceration have also been described: one with ulceration in the winter and one with edema of the ankles and ulceration in the spring and summer.
Ulcers are small but painful and heal with atrophic-pigmented scars. Skin biopsies have shown fibrinoid necrosis of small blood vessels, hyaline thrombi and mild perivascular lymphocytic infiltrates. Treatment involves advising the patient to avoid the cold and treating the primary condition.
Venous drainage at the margins of areas of the skin richly supplied by arterial cones is believed to cause the netlike pattern. When factors, including cold, arteriolar disease and blood hyperviscosity, reduce blood flow rates in the superficial venous plexus, the cyanotic reticular pattern becomes more pronounced.
A mottled bluish discoloration of the skin that occurs in a netlike pattern that is not a diagnosis in itself, but rather, a nonspecific reaction pattern either idiopathic in nature or secondary to other medical conditions including Sneddon’s disease systemic lupus erythematous, periarteritis nodosa and cryoglobulinemia.
Livedo reticularis is a progressive cerebrovascular condition that precedes neurologic symptoms by several years. Due to similarities in appearance, the disorder must be distinguished from cutis marmorata, a transient physiologic reaction to the cold that occurs in about half of all children and adults.