Elastosis perforans serpiginosa is a rare, primary perforating dermatosis, frequently associated with certain genetic diseases and characterized by the transepidermal extrusion of elastic fibers. The present case report describes this dermatosis in a 19-year old female patient with Down's syndrome, who presented with asymptomatic erythematous, keratotic papules in an arciform pattern, located on her right forearm and knee, which had been present for five years. Following histopathological confirmation, treatment with cryotherapy was initiated, resulting in partial remission of the lesions. Keywords: Conjunctive tissue; Down's syndrome; Elastic tissue; Elastic tissue abnormalities Resumo: A elastose perfurante serpiginosa é dermatose perfurante primária incomum, frequentemente associada a determinadas doenças genéticas e caracterizada por eliminação transepidérmica de fibras elásticas. Relata-se um caso raro dessa dermatose em paciente feminina de 19 anos, portadora da sín-drome de Down, que apresentava pápulas eritematoceratóticas em arranjo arciforme, localizadas no antebraço e joelho direitos, assintomáticas, com cinco anos de evolução. Após confirmação histopatológica, foi iniciado tratamento com crioterapia, ocorrendo remissão parcial das lesões.