Sinus infections may cause more than 20 percent of all cases of toxic shock syndrome, said Chan.
The study appears in this month's issue of the Archives of Otolaryngology.
Toxic shock is caused by toxins produced by bacteria. Symptoms include fever, rash, a drop in blood pressure and in very rare cases, death.
Chan and his colleagues examined the medical records of 76 children who had toxic shock syndrome. They found a third also had sinus infections.
"It is imperative that physicians, particularly those who are providing intensive care to children, recognize that rhinosinusitis can be the sole cause of toxic shock syndrome in children," Chan and colleagues wrote in the study.