Influenza-like illness

Influenza-like illness, also called flu-like syndrome, is a clinical diagnosis given to a set of common symptoms that suggest possible influenza or another respiratory illness, including fever, shivering, chills, malaise, a dry cough, loss of appetite, body aches, nausea, and sneezing, typically appearing suddenly. In most cases these symptoms are caused by cytokines released as the immune system activates in response to infection, which is why the symptom pattern is relatively non-specific and can arise from many different infectious agents, not influenza alone.