We conducted a clinical description of confrmed dengue cases admitted to the Hospital "César Garayar García" in Iquitos from January 25 to February 5, 2011. According to current WHO classifcation, major warning signs leading to hospitalization were: abdominal pain (28/28) and persistent vomiting (15/28), the causes of severity were: hypotension (9/13), severe bleeding (6/13) and plasma extravasation with respiratory distress (4/13). The median patient age was 22 years, however, 8/13 patients classifed as severe dengue were under 16 years. In conclusion, unlike previous epidemics, we found a high involvement of young people and severity in the clinical presentation predominating a high frequency of shock (hypotension) and vascular leakage, which could be related to the circulation of an emerging variant DENV-2 which is more virulent.