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Cinnamal allergy

Radosław Śpiewak¹,² ORCID iD icon

¹ Institute of Dermatology, Kraków, Poland
² Dermatology and Allergology Outpatient Clinic ‘dermatolog.eu’, Kraków, Poland

Keywords: allergic contact dermatitis, cinnamal, cinnamic aldhehyde, contact allergy

Suggested citation: Śpiewak R (2025) Cinnamal allergy. Allergopedia 1: 1. doi: 10.14320/allergopedia.20250101

Cinnamal, also known as cinnamaldehyde, is a commonly used fragrance and flavouring agent. It can also be a component of fungicides, insecticides, and animal repellents. It is also present to a greater or lesser extent in a range of natural products, including essential oils, e.g., Myroxylon Pereirae Resin (balsam of Peru), Myroxylon Balsamum Balsam Oil (Tolu balsam), and Cinnamomum Zeylanicum Leaf Oil (cinnamon oil).

Synonyms and names in other languages

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

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 containing cinnamal, including some medicinal products, cosmetic / toiletry products, foods, and spices. Perioral leukoderma (depigmentation simulating vitiligo) from use of toothpaste containing cinnamic aldehyde was reported by Mathias et al. (1980).

Cinnamal in cosmetic products / toiletries

Cinnamal is to be found in a range of cosmetic products, including balms, creams, soaps, emulsions, shower gels, bath foams, toothpastes, mouthwashes, and dental flosses. According to Regulation (EC) No 1223/2009 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

Over 500 cinnamal-containing cosmetic products and toiletries can be found listed on INCIDecoder

INCI: International Nomenclature of Cosmetic Ingredients — In the UK, the European Union, and in other global regions, manufacturers of cosmetic products are legally required to list ingredients on product labels / packaging using standardised INCI nomenclature. The Personal Care Products Council cautions that "The designation of an INCI name for a cosmetic ingredient is an essential part of ingredient identification; however, the assignment of an INCI name does not mean that the ingredient has been approved for cosmetics."

Cinnamal in medicinal products

Medicinal products may contain cinnamal as a fragrancing additive. The presence of cinnamal is disclosed in the following:

  • Dicloziaja™ gel
  • Nizoral® 20 mg/g shampoo
  • There may be others – please always check the composition of the product you are going to use or ask your doctor, pharmacist or other health care professional

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. It is also present in spices, and in particular in cinnamon. It is identical with the cinnamal present in cosmetics, therefore, people with allergic contact dermatitis caused by external exposure to cinnamal could also develop contact eczematous reactions to cinnamal in food depending on the total amount and concentration. Systemic reactivation of allergic contact dermatitis (i.e. hematogenous contact eczema, where, following absorption, the hapten is carried by the blood to other parts of the body) may also occur following ingestion of food containing cinnamal. Such hematogenous eczema following ingestion of balsam of Peru, which contains cinnamal, has been reported (Erdmann & Werfel 2006). Such reactions were referred to as SRACD – systemic reactivation of allergic contact dermatitis – by Spiewak (2011).

Available diagnostic methods and materials

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

  • Cinnamal 1% pet. [Chemotechnique Diagnostics, cat. number C-014]
  • Fragrance Mix I 8% pet. [Chemotechnique Diagnostics, cat. number Mx-07] – 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 (Schnuch et al. 2007, Uter et al. 2010).

Cross-reactivities, co-positivities, and co-sensitizations

Cinnamal (cinnamaldehyde) is present in Myroxylon Pereirae Resin (balsam of Peru), Myroxylon Balsamum Balsam Oil (Tolu balsam), cinnamon oils, e.g., Cinnamomum Zeylanicum Leaf Oil, oil of hyacinth, etc. Cinnamal constitutes up to 92% of Cinnamomum Cassia Bark Oil and up to 55% of Ceylon Cinnamon Bark Oil (De-Montijo-Prieto et al. 2021). Cross-sensitivities to cinnamic aldehyde were considered by Collins & Mitchell (1975).

References

  • Collins FW, Mitchell JC (1975) Aroma chemicals. Reference sources for perfume and flavour ingredients with special reference to cinnamic aldehyde. Contact Dermatitis 1(1): 43-47. doi: 10.1111/j.1600-0536.1975.tb05310.x
  • De-Montijo-Prieto S, Razola-Díaz, MdC, Gómez-Caravaca AM, Guerra-Hernandez EJ, Jiménez-Valera M, Garcia-Villanova B, Ruiz-Bravo A, Verardo V (2021) Essential oils from fruit and vegetables, aromatic herbs, and spices: composition, antioxidant, and antimicrobial activities. Biology 10(11): 1091. doi: 10.3390/biology10111091
  • Erdmann SM, Werfel T (2006) Hämatogene Kontaktekzeme durch Nahrungsmittel [Hematogenous contact eczema induced by foods]. Hautarzt 57(2): 116-120. doi: 10.1007/s00105-005-1079-2
  • Lazarov A, David M, Abraham D, Trattner A (2007) Comparison of reactivity to allergens using the TRUE Test and IQ chamber system. Contact Dermatitis 56(3): 140-145. doi: 10.1111/j.1600-0536.2007.01025.x
  • Mathias CGT, Maibach HI, Conant MA (1980) Perioral leukoderma simulating vitiligo from use of a toothpaste containing cinnamic aldehyde. Archives of Dermatology 116(10): 1172-1173. doi: 10.1001/archderm.1980.01640340082022
  • Schnuch A, Uter W, Geier J, Lessmann H, Frosch PJ (2007) Sensitization to 26 fragrances to be labelled according to current European regulation. Results of the IVDK and review of the literature. Contact Dermatitis 57(1): 1-10. doi: 10.1111/j.1600-0536.2007.01088.x
  • Śpiewak R (2011) Food-provoked eczema: a hypothesis on the possible role of systemic contact allergy to haptens present in both cosmetics and foods. Wyprysk prowokowany przez pokarmy: Hipoteza na temat możliwej roli układowej alergii kontaktowej na hapteny występujące w kosmetykach i pokarmach. Estetologia Medyczna i Kosmetologia 1(1): 35-40. doi: 10.14320/EMK.2011.006
  • Uter W, Geier J, Frosch P, Schnuch A (2010) Contact allergy to fragrances: current patch test results (2005-2008) from the Information Network of Departments of Dermatology. Contact Dermatitis 63(5): 254-261. doi: 10.1111/j.1600-0536.2010.01759.x

Disclaimer

The information provided above is not exhaustive, and the irritant / sensitizer to which you react may also be present in sources not listed above. Therefore, always check the composition of the products and substances with which you come into contact. If in doubt, consult a licensed physician, preferably a dermatologist or an 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 assume no responsibility or liability for any damages resulting from the application of the information provided. Use of this work constitutes acceptance of this disclaimer and a waiver of any claims arising from its use.

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Document created: 14 October 2025; last updated: 10 September 2026

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