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Cinnamal allergy

Radoslaw Spiewak

Institute of Dermatology, Krakow, Poland

Key words: cinnamal, cinnamic aldhehyde, contact allergy, allergic contact dermatitis.

Suggested citation format: Spiewak R. Cinnamal allergy. Allergopedia. 2025; 01: 01. DOI: to be announced

Cinnamal, synonym cinnamaldehyde, is a commonly used fragrance and flavoring agent. It can also be a component of fungicides, insecticides, and animal repellents. It is also present in a range of natural products, including essential oils, e.g., Myroxylon pereirae resin (Peruvian balsam) and Tolu balsam (see below).

Clinical symptoms of cinnamal allergy

In most cases cinnamal causes skin inflammation (allergic contact dermatitis or eczema) limited to areas directly exposed to cinnamal by skin contact. Typical symptoms of cinnamal allergy include patches of itchy rash in the area of contact with products or natural substances releasing cinnamal, cosmetic products, some foods, spices. Systemic reactivation of allergic contact dermatitis, i.e., dermatitis due to systemic exposure via ingestion or inhalation, e.g. from food containing cinnamal, but infrequently reported. Hematogenous eczema due to absorption of cinnamal at the primary contact site and redistribution to other skin areas via bloodstream is also possible, however, has not been reported until present. Cinnamaldehyde may cause depigmentation (discoloration) of the skin.

Cinnamal in cosmetics

Cinnamal can be found in a range of cosmetic products, including balms, creams, soaps, emulsions, shower gels, bath foams, toothpastes, mouthwashes, dental flosses, etc. According to the EU Regulation on cosmetic products, Annex III, item 76, the presence of cinnamal must be indicated in the list of ingredients when its concentration exceeds 0,001% in leave-on products or 0,01% in rinse-off products.

  • INCI*: CINNAMAL

INCI: International Nomenclature of Cosmetic Ingredients - unified, international names for cosmetic ingredients. Information about ingredients is provided on cosmetics packaging according to the INCI nomenclature. CI: Colour Index, a unique number of a dye in the Colour Index™ International (CI) reference database.

Cinnamal in medicinal products

Drugs may contain cinnamal as a scenting or flavoring additive. The presence of cinnamal is disclosed in case of the following medicinal products:

  • Nizoral® 20 mg/g shampoo
  • Dicloziaja gel

Cinnamal in household products

Cinnamal can be used for scenting a variety of household products, e.g., detergents, fabric softeners, air fresheners, or scented candles.

Cinnamal in food

Cinnamal may be an additive or natural component in sweets, ice creams, soft drinks, chewing gums, and cakes. Also present in spices, in first instance in cinnamon.

Synonyms and names in other languages

Cinnamal, Cinnamic aldehyde, Cassia aldehyde, 2-Propenal-3-phenyl, 3-phenylacryaldehyde, 3-Phenyl-2-propenal, 3-Phenyl-2-propen-1-al, Cinnamyl aldehyde, 3-phenylpropenal, Benzylideneacetaldehyde, Phenylacrolein, 3-phenylacrolein, Phenyl-2-propenal, 3-phenyl-2-propenaldehyde, Zimtaldehyd; Aldehyd cynamonowy; CAS# 104-55-2; EC# 203-213-9

Available diagnostic methods and materials

At present, the only validated method of detecting cinnamal allergy is patch test performed in line with the current guidelines by national or intenational scientific societes, e.g., European Society of Contact Dermatitis. Patch test material available for testing includes:

  • Cinnamal 1% pet.
  • Fragrance Mix I 8% pet. present in European Baseline Series and many other series contains cinnamal 1% as one of its 8 ingredients.
  • Fragrance Mix 500 µg/cm2 of Panel 1.3 of T.R.U.E.® Test contains cinnamal (cinnamaldehyde) at 41 µg/cm2 among its 8 ingredients. Comparative studies have shown that its detection rate is lower than for Fragrance Mix I 8% pet. [Lazarov et al. 2007].

Positivity rate

0.7-2.2% of patients undergoing patch testing due to chronic, recurrent eczema.[1,2]

Cross-reactivities, co-positivities and co-sensitizations

Cinnamal is present in Myroxylon pereirae resin (Peruvian balsam) and Tolu balsam, hyacinths, spices (cinnamon), and Ceylon oil. Cinnamaldehyde constitutes up to 92% of Cassia essential oil and up to 55% of Ceylon essential oil [3].

Disclaimer

The above description does not exhaust all possible exposures and symptoms, and the hapten you are allergic to may also be present in other sources not listed above.Therefore, always check the composition of the products and substances you come into contact with, and if in doubt, consult a licensed physician, preferably a dermatologist or allergist.
The authors, reviewers, editors and publisher of this work have made every effort to ensure that the content presented reflects the current state of knowledge at the time of its preparation. However, scientific progress may render some information outdated or inaccurate. Therefore, the authors, reviewers, editors, and publishers of this work exclude all liability for damages that may arise as a result of using the information presented. Use of this work constitutes acceptance of this disclaimer and a waiver of any claims arising from its use.

References

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Document created: 14 October 2025, last updated: 12 May 2026
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© Radoslaw Spiewak Instytut Dermatologii