Table Red flags The following findings are of particular concern: Age < 1 month Lethargy, listlessness, or toxic appearance Respiratory distress Petechiae or purpura Inconsolability Interpretation of findings Although serious illness does not always cause high fever and many high fevers result from self-limited viral infections, a temperature of ≥ 39 ° C in children < 36 months indicates higher risk of serious bacterial infection.