The bacterium that causes SSSS is common in healthy people. According to the British Association of Dermatologists, 40 percent of adults carry it (usually on their skin or mucous membranes) with no ill effects.
Problems arise when the bacteria enter the body through a crack in the skin. The toxin the bacterium produces damages the ability of the skin to hold together. The upper layer of skin then breaks apart from the deeper layers, causing the hallmark peeling of SSSS.
The toxin can also enter the bloodstream, producing a reaction all over the skin. Because young children — especially newborns — have underdeveloped immune systems and kidneys (to flush the toxins out of the body), they’re most at risk. According to research published in the journal Annals of Internal Medicine, 98 percent of cases occur in children under 6. Adults with weakened immune systems or poor kidney function are also susceptible.