Erythema gyratum repens. Greek: gyrate, a circle Latin: repens, to creep.
Clinically distinctive figurate reactive erythema. Regular waves of erythema spread over the body (the complete torso is frequently affected, often associated with severe pruritus) to produce a series of concentric, figurate bands in a pattern resembling the grain of wood. More striking is the relatively rapid rate at which lesions migrate (day-to-day migration of the leading edge: about 1 cm).
In the more common figurate erythemas, this concentric arrangement is lacking. About 80% of reported cases are associated with an internal tumour (paraneoplastic eruption). Lung cancer is present in about a third of these cases. Resection of the tumour often results in resolution of the eruption. Not all cases are paraneoplastic; it has been associated with e.g. tuberculosis. Drug hypersensitivity has also been implicated. Cases of apparent idiopathic erythema gyratum repens have been suggested to represent a stage in the evolution of pityriasis rubra pilaris. Fungal infection should be excluded, especially tinea imbricata.
Skin biopsy is important (though the histopathology of erythema gyratum repens is nonspecific) as a similar gyrate eruption may be a prodromal manifestation of pemphigoid, and similar but rather localized lesions have been reported due to vasculitis, especially in lupus erythematosus and in neutrophilic dermatoses.