NCIS star Pauley Perrette was recently hospitalized due to a severe allergic reaction to the black hair dye she uses. Now the 45-year-old actress has warned her fans of the dangers of hair coloring.

Perrette plays a goth-inspired forensic scientist named Abby Sciuto on NCIS, and keeps her hair jet black for the role. Perrette, a natural blonde, had been darkening her hair for roughly twenty years, without any serious issues. Though recently, the New Orleans-born actress developed a rash, along with severe swelling.

“The other half of my face had become twice the size of my head,” Perrette explained, and posted the following picture to Twitter while she was in the hospital on July 19:

This was me at hospital today and it got worse #Allergy #AllergicReaction PLEASE read my next tweet http://t.co/AYf4GfM3sm

— Pauley Perrette (@PauleyP) July 19, 2014

Perrette warns of the perils of hair dye allergies:

PLEASE read and see prior twitpic: #AllergicReaction #HairDye #PPD I'm ok, but this is serious: http://t.co/OtiSU6Pk0l

— Pauley Perrette (@PauleyP) July 19, 2014

Commenting on allergic reactions to hair dye, Perrette explained, “The most important thing to me is that anyone out there that dyes their hair, particularly black, you need to be aware of the symptoms.”

Jacob Offenberger, an allergist at Northridge Medical Center, said, “If you have hair dye, and the next day or the day after you start to have itchiness and you start to see redness or [an] eczema-type of lesion, it is telling that you that you are having an allergic reaction to that dying. If you would do nothing, the next time you do the hair dye, it’s going to get worse.”

Perrette experienced the same progression – six months before winding up in the hospital, she developed a rash on her scalp and neck, but ignored the symptoms.

Perrette says she is now researching natural hair dye and also looking into wearing a wig, and is back on the NCIS set with her fellow cast mates.

Happy to report I'm back on #NCIS set with the gang. Thanks everyone! http://t.co/ivhVDBUhHy

— Pauley Perrette (@PauleyP) July 24, 2014

Image via Wikimedia Commons