Authors describe a case of dengue fever, accidentally seen for appearance of purple at the lower limbs, fever and fatigue. They want to signal this case not for the difficulty of the diagnosis, because the patient was just arrived from Venezuela and he went, during his travel, in endemic zones for dengue, but because this illness is very uncommon in our Country. Diagnosis was confirmed with the presence of antibody in the serum of the patient and treatment was limited to a careful monitoring of laboratory examination and at an hydratation. Recovery with return to normal value of renal and hepatic function was obtained after 15 days.