About 1000 patients were investigated at our clinic during 1991-1995 for occupational skin disease, and 5 had occupational allergic contact dermatitis from spices. The patients were chefs, or kitchen, coffee room, and restaurant workers. All patients had hand (or finger) dermatitis.
– Contact Dermatitis 1996 Sep;35(3):157-62 — Occupational allergic contact dermatitis from spices. — Kanerva L, Estlander T, Jolanki R. — Section of Dermatology, Finnish Institute of Occupational Health, Finland.

Erythema multiforme, or EM, is a hypersensitivity reaction to agents such as herpes virus, drugs or foods. Oral EM-like reactions may be induced by cinnamon. It is important for dentists to recognize this condition. The authors report an unusual case of cinnamon-induced oral EM-like reaction in an older female patient. The disease manifested itself as chronic extensive surface ulcerations and lip swelling. The patient was treated repeatedly with topical and systemic steroids but responded to them only temporarily. The patient was cured when the offending agent–cinnamon–was eliminated from her diet.
– J Am Dent Assoc 2000 Jul;131(7):929-34 — Cinnamon-induced oral erythema multiformelike sensitivity reaction. — Cohen DM, Bhattacharyya I.

Cinnamon linked to oral sores, irritation.

– J Am Dent Assoc 1995 Sep;126(9):1214 — Cinnamon linked to oral sores, irritation.

Toxic manifestations of cinnamon oil ingestion in a child.
– Toxic manifestations of cinnamon oil ingestion in a child. — Pilapil VR.
Clin Pediatr (Phila). 1989 Jun;28(6):276.

Oral lesions induced by contact with cinnamon flavoring agents are relatively uncommon, and are probably unrecognized as such by many clinicians. Ten patients with these lesions seen during the past 6 years are described in this report. Most patients had a “burning sensation” as their primary symptom. Clinically, lesions appeared as erythematous patches with varying degrees of superimposed keratosis or ulceration, or both. The lesions were usually confined to the buccal mucosa and lateral border of the tongue. The offending agent was almost always cinnamon-flavored chewing gum, and symptoms typically resolved within 1 to 2 days of discontinuing the product containing cinnamon.

– J Am Dent Assoc 1988 May;116(6):664-7 — Oral mucosal reactions to cinnamon-flavored chewing gum. — Allen CM, Blozis GG. — Diagnostic Services, Ohio State University, College of Dentistry, Columbus 43210.

A patient had acute stomatitis and dermatitis due to a popular toothpaste containing cinnamon oil flavor. Cinnamon cassia oil is known as a topical sensitizer and was demonstrated to be the offending allergen. Cinnamic aldehyde and related chemicals are used widely, so that patients having cinnamon allergy may be exposed to many sources.

– Arch Dermatol 1976 Feb;112(2):202-3 — Allergic contact dermatitis and stomatitis caused by a cinnamic aldehyde-flavored toothpaste. — Drake TE, Maibach HI.

Not recommended for use by pregnant women.

– Blumenthal M, Busse WR, Goldberg A, et al. — The Complete Commission E Monographs: Therapeutic Guide to Herbal Medicines. — Integrative Medicine Communications, 1998.