Reticulate eruptions: Part 2. Historical perspectives, morphology, terminology and classification

Abstract

Reticulate eruptions of vascular origin may represent an underlying arterial, venous, microvascular or combined pathology. In the presence of arterial pathology, individual rings are centred around ascending arterial vessels that supply the corresponding area of skin within an arterial hexagon that clinically presents with a blanched centre. Confluence of multiple arterial hexagons generates a stellate (star-like) pattern. In the presence of a primary venous pathology, individual rings correspond to the underlying reticular veins forming multiple venous rings. Focal involvement of a limited number of vessels presents with a branched (racemosa) configuration while a generalized involvement forms a reticulate (net-like) pattern. 'Livedo' refers to the colour and not the pattern of the eruption. Primary livedo reticularis (Syn. cutis marmorata) is a physiological response to cold and presents with a diffuse blanchable reticulate eruption due to vasospasm of the feeding arteries and sluggish flow and hyperviscosity in the draining veins. Livedo reticularis may be secondary to underlying conditions associated with hyperviscosity of blood. Livedo racemosa is an irregular, branched eruption that is only partially-blanchable or non-blanchable and always signifies a pathological process. Retiform purpura may be primarily inflammatory with secondary haemorrhage or thrombohaemorrhagic, as seen in disseminated intravascular coagulopathy.

Atypical presentation of livedo racemosa in a factor V Leiden heterozygous positive patient with Pseudomonas aeruginosa urosepsis

“…Despite having some similar aetiologies, the morphology and behaviour of livedo racemosa and livedo reticularis further distinguish them from one another as separate dermatological prodromes . Livedo reticularis presents with a symmetrical blanching, net‐like transient violet mottling of the skin.…”

“…This normally occurs when there is vascular stasis in the s.c venous plexus in the region of the skin involved. It normally is a physiological response to the cold like cutis marmorata with its distinguishing feature of resolving dermal blanching upon physiological warming …”

“…It normally signifies an underlying vascular pathology and does not resolve with physiological warming. Vasculopathy usually occurs from thrombosis in medium‐sized arterioles in part from dysfunctional coagulation haemostasis …”

Livedo Reticularis on the Lower Limbs in a Patient with Lupus Erythematosus: A Quiz

“…Elodie MIQUELESTORENA-STANDLEY 1,2 , Alia SALEH 3 The diagnosis was suspected clinically because of some epidermal changes visible on clinical examination, with mild desquamation; the lesions were not infiltrated on palpation; the fishnet livedo pattern was very regular and associated with brown-yellowish pigmentation of the lesions on the left knee (1,2). Moreover, the patient received warfarin with target INR approximately 2.5, therefore the diagnosis of thrombosis was less likely.…”

“…Livedo reticularis is permanent livedo that does not disappear with warming of the involved skin. It is termed regular when the annular lesions form complete unbroken circles, as on the left knee of the current patient, and termed livedo racemosa when the annular lesions form incomplete circles, as on her right knee (3). The occurrence of livedo reticularis in a patient with SLE is potentially lifethreatening, and clinical and biological signs of venous or arterial thrombosis need to be checked, and tests performed for lupus anticoagulant, antiphospholipid and anti-beta-2 glycoprotein-1 antibodies.…”