The increasing expansion and magnifying of the cases for all Brazil had determined a new vision in the clinical evaluation of the dengue. Until few years, with the restricted knowledge, the dengue was classified only as classic or hemorrhagic. Today, however, with the clinical experience of innumerable cases, we perceive many manifestation forms of this illness. Thus, to trace the diagnosis of dengue, based only on the features of its multiple presentations ways, reveals to be a clinical reasoning exercise example.