TikTok Star Taylor Rousseau Grigg Cause of Death Revealed

Some clarity on TikTok star Taylor Rousseau Grigg's sudden and unexpected passing ... her family is announcing her cause of death.

The 25-year-old influencer died as a result of complications related to Addison's disease and asthma ... a rep for her family told TODAY.

As we reported ... Taylor died last Friday, with her husband saying her passing was "so sudden and unexpected." He also said, "This past year Taylor has dealt with more pain and suffering than most people do in a lifetime."

Addison's disease is a rare disorder that occurs when the adrenal glands do not produce enough of the hormones aldosterone and cortisol ... according to the Mayo Clinic. It's also known as primary adrenal insufficiency.

Taylor talked a little bit about her health issues in the months before her death ... in August she told her 1.4 million followers she's been "fighting for my life every day" ... saying she was going through indescribable pain that was so bad it had her sometimes wishing she was dead.

TRG also told her followers she had been medically diagnosed by a doctor, though she never detailed what exactly she was going through.