In a report of one patient, cinnamon was potentially linked to an increase in severity of the patient's rosacea, according to a report in the Journal of Drugs in Dermatology.1
Researchers Dr. Tracy Campbell and colleagues at Rush University Medical Center in Chicago reported that a woman with diabetes and mild papulopustular rosacea on the nose experienced a sudden spread of symptoms from her eyelids to her chin after using 500-mg cinnamon supplements to help control blood sugar levels.
Cinnamon has vasodilatory properties, the researchers noted, and can also provoke an allergic reaction in some.
Campbell TM, Neems R, Moore J. Severe exacerbation of rosacea induced by cinnamon supplements. Journal of Drugs in Dermatology. 2008;7:586-587.