Palmar Cutaneous Erythematous Macules: A Case Report of an Atypical Presentation of Chilblain Lupus Erythematosus.

Systemic lupus erythematosus (SLE) manifests with a broad spectrum of cutaneous manifestations, including chilblain lupus erythematosus (CHLE), which typically presents as cold-induced, painful acral lesions with specific dermatoscopic and histopathologic features. We describe an unusual case of a 32-year-old woman with established SLE and stage IV lupus nephritis who presented with a five-year history of asymptomatic, recurrent erythematous macules on the palms.  The patient reported no cold sensitivity, pain, or Raynaud's phenomenon, which are hallmark features of classic CHLE. Physical examination revealed irregularly shaped pink macules and patches on the volar aspect of the fingers and thumb base and dorsal hands, sparing the palms. Dermoscopy showed well-demarcated, non-scaling pink macules with nonspecific white dots and sparing of palmar skin lines. Histopathological analysis demonstrated superficial and deep perivascular lymphocytic infiltrates with increased dermal mucin. Direct immunofluorescence revealed granular IgM and IgG deposits at the dermoepidermal junction, supporting a lupus-related process. Although the patient met the histopathologic and minor clinical criteria for CHLE, the absence of cold triggers and pain suggests an atypical presentation of CHLE or a distinct variant of lupus-associated palmar macules. Differential diagnoses, including dermatomyositis and small-vessel vasculitis, were excluded through clinical and laboratory evaluations. This case highlights the clinical variability of cutaneous lupus and the diagnostic challenges posed by palmar lesions that do not strictly adhere to established diagnostic criteria for CHLE.