TSS is a rare but dangerous disease, which can occur with men, women, and children. At the moment, there have not been many known cases to be connected with a menstrual cup, but still: extreme cases of TSS can lead to death.
The following symptoms, which can develop very quickly and appear to only be influenza in the beginning:
Sudden high fever (>39°C / >102°F), nausea, diarrhea, sunburn-like rash, sore throat, vertigo, and/or fainting.
If you experience one or more of these symptoms during your menstruation, remove the cup and consult with a doctor immediately. Mention TSS and that you are menstruating. This way, it is possible to diagnose the disease early and treat it effectively. If you are already affected by TSS, consult with your doctor before using cups or tampons.