The most common reason for confusion with FSF is the wildly but incorrectly held belief that it's the fevers that could take the dogs' life. In other words, attentive owners will immediately spot the swollen hocks. After taking the dog's temperature, they will notice the fever, which can be extreme (reports of 41.1°C/106°F are frequent, while potentially lethal 41.7°C/107°F has been observed).

However, that is not the case. The actual danger/killer is hidden: during the fever episodes, internal damage is caused to the dog. Chemical signals called "inflammatory cytokines" contribute to the production of a protein called "amyloid". This amyloid makes its way to various internal organs, resulting (sometimes, but not always) in a condition called "amyloidosis".

These deposits are particularly problematic when they affect the kidneys, and recurrent episodes can lead to kidney failure over time. To make matters worse, even a biopsy may not show a conclusive amyloidosis diagnosis. At the same time, the dog could still be affected by chronic kidney disease and even kidney failure, just like what happened to my own Shar Pei, "Pillow".