Contact Allergy to (Ingredients of) Toothpastes.

The literature on contact allergy to (ingredients of) toothpastes is critically reviewed. We have found 47 case reports, small case series (n = 2-5) and citations published between 1900 and 2016 describing more than 60 patients allergic to toothpastes, and in addition 3 larger case series and many descriptions of toothpaste allergy among selected groups of patients. Allergic reactions usually manifest as cheilitis with or without dermatitis around the mouth, less frequently by oral symptoms. Formerly, many reactions were caused by cinnamon derivatives; more recently, reported allergens are diverse. A semiopen test or closed patch test with the toothpaste "as is" may be performed as an initial test, but a positive reaction should always be followed by confirmatory tests. The role of contact allergy to toothpastes in patients with oral symptoms (stomatitis, glossitis, gingivitis, buccal mucositis, burning, soreness, and possibly burning mouth syndrome and recurrent aphthous ulcers) is unclear and should be further investigated.