Staphylococcus aureus
There is no certainty about the cause of this disorder, but the bacterial species "Staphylococcus aureus" has a central role and can be detected in the lesions of most patients. It is unclear if another primarily sterile process with secondary colonization by "Staphylococcus aureus" is present, or if Staphylococcus aureus starts the process by causing a strong immune reaction. Another possibility is that "Staphylococcus aureus" produces toxins that act as superantigens which directly activate the T-cells over the variable domain of T-cell receptors. Nonetheless "Staphylococcus aureus" can by found in almost all patients affected by this disorder, while it is detected in only 20–30% of non-affected people.