The prevalence of livedo reticularis and racemosa in SARS-CoV-2 patients is between 0.6 and 6% and they occur more frequently in adults than children. In a case series study of 719 patients, Freeman et al. reported that livedoid reticularis represented 3.5% and livedoid racemosa represented 0.6% of all SARS-CoV-2-related cutaneous manifestations. Livedoid lesions present with symmetric, lace-like dusky patches forming pale-centered rings along blood vessels. On the other hand, livedoid racemosa have irregular and asymmetrical dusky patches along blood vessels. These lesions last for an average of 9.4 days.
Livedoid lesions are the result of the activation of the complement system leading to increased coagulation resulting in microvascular injury.
The histopathology of these lesions includes epidermal necrosis, superficial and deep dermis thrombosis vasculopathy in small and medium vessels, sweat gland necrosis, mild perivascular lymphocytic infiltrate and complement deposition in the vessel walls.[13,29] Leukocytoclastic vasculitis is absent. Evidence of complement deposits in the microvascular have been seen in normal-appearing skin tissue.
Treatment options for livedoid lesions vary widely in pediatrics and adults. Intensive care support tends to be needed in adults with livedoid lesions. In severe cases, necrosis may be present along with scabbing and sloughing of the skin.
Active non-intervention is a consideration for milder lesions, while symptomatic treatment to intensive supportive measures can be used for severe cases.
Am J Clin Dermatol. 2022;23(3):277-286. © 2022 Adis Springer International Publishing AG