Content » Vol 90, Issue 2

Letter to the Editor

Allergic Contact Dermatitis due to Cinnamon Oil in Galenic Vaginal Suppositories

Maria Michela Lauriola1, Antonio De Bitonto1 and Paolo Sena2

1Policlinico San Marco di Zingonia, UO di Dermatologia, Corso Europa 7, IT-24046 Zingonia/Osio Sotto (Bergamo) and 2Università degli Studi di Milano, Scuola di Specializzazione in Dermatologia e Venereologia, Ospedali Riuniti di Bergamo, USC Dermatologia, Bergamo. Italy. E-mail:

Accepted October 12, 2009.


Medicaments containing various botanical extracts (e.g. tea tree oil, aloe, calendula, Echinacea, propolis) with purported therapeutic benefits are used widely by patients, who often prefer alternative medicine to traditional topical and systemic pharmacological treatments. Numerous over-the-counter herbal-based products are available.

We report here an unusual case of allergic contact dermatitis in a young woman following topical use of galenic vaginal suppositories containing natural substances.


An 18-year-old girl developed two symmetrical erythemato-oedematous patches on the glutei, leading to an acute eczema. Erythematous vulvitis and thick leucorrhoea were also present.

In order to treat a persistent vulvar itch that had been present for the past weeks, the patient had used Kolorex® cream and galenic vaginal suppositories. The phytotherapic topical medicament (Kolorex® cream, Named S.r.l., Lesmo, Italy) contained tea tree oil (Melaleuca alternifolia), Aloe barbadensis and Pseudowintera colorata extract. The galenic vaginal suppositories contained tea tree oil (2%) and cinnamon oil (3%). The patient had used both products previously. She had no history of atopy.

After 4–5 days, the patient’s vulvitis worsened and an acute pruritic eczematous eruption developed on her buttocks (Fig. 1). Allergic contact dermatitis was suspected and use of the two ointments was suspended. The dermatitis healed following treatment with oral antihistamines, systemic and topical steroids.

Patch tests with the Italian standard SIDAPA (Società Italiana di Dermatologia Allergologica Professionale e Ambientale (Italian society of allergologic occupational and environmental dermatology); series were performed using standardized allergens (FIRMA Spa, Firenze, Italy) with a positive result for fragrance mix 8% pet (++D2/+++D3). This positive reaction was considered relevant for the dermatitis, as these substances were present in topical products used by the patient.


Fig. 1. Allergic contact dermatitis to vaginal suppositories, due to their spreading when the patient laid down in bed.

The Kolorex® cream and galenic vaginal suppositories were also tested in single application occlusive patch tests. A strong positive reaction to vaginal suppositories (++D2/+++D3) was observed, whereas the patch test with Kolorex® cream was negative.

Patch tests were performed with the components of the galenic vaginal suppositories, kindly provided by the manufacturer. These tests revealed positive reactions only to cinnamon oil 3% pet (++D2/++D3) and 1% pet (+D2/+D3), but not at lower concentrations (0.5% pet) (Table I).

Table I. Patch test results on days 2 and 3, respectively

Day 2

Day 3

Standard Italian series

Fragrance mix 8% pet

Balsam Peru 25% pet

Patient’s own medicaments

Galenic vaginal suppositories, as is

Kolorex® cream, as is

Constituents of galenic vaginal suppositories

Tween 80, 5% pet

Tea tree oil, 5% pet

Cinnamon oil 3% pet

Cinnamon oil 1% pet

Cinnamon oil 0.5% pet

Tea tree oil 2% pet

Gelatinoid vehicle, as is

Specific fragrance series

Cinnamic acid, 5% pet

Benzyl alcohol, 5% pet

Cinnamaldehyde, 2% pet

Eugenol, 5% pet

Cinnamic alcohol, 5% pet

Hydroxycitronellal, 5% pet

Isoeugenol, 5% pet

Oakmoss absolute, 2% pet

Vanillin, 10% pet

Amylcinnamaldehyde, 2% pet











pet: in petrolatum

Patch tests performed with cinnamon oil at concentrations of 3% and 1% and with fragrance mix 8% pet in 10 controls did not elicit any reaction.

Further patch tests were carried out, using standardized products (FIRMA Spa, Firenze, Italy), with the separate fragrances of the mix previously tested and the main constituents of cinnamon oil. Among 10 substances tested, only cinnamic alcohol at 5% pet gave a positive reaction (+D2/++D3), whereas patch tests with cinnamaldehyde, cinnamic acid and eugenol were negative (Table I).

Allergic contact dermatitis to cinnamon oil containing cinnamic alcohol was therefore diagnosed. The localization of two symmetrical eczematous patches on the patient’s buttocks can be explained by spreading of the vaginal suppositories when she laid down in bed, after an evening application (Fig. 1).


Cinnamon is an ancient oriental spice obtained from one of Lauraceae trees (Cinnamomum verum or zeylanicum). It is widely used in the food, in cosmetics and as a natural remedy due to its anti-microbial and fungicidal properties (1, 2).

Cinnamon oil (usually diluted at 0.5–2.5%) is more often derived from the bark than from the leaves of the tree. Its main components are cinnamaldehyde (65–80%), trans-cinnamic acid (5–10%) and eugenol (4–10%); other constituents include cinnamic alcohol, terpenes such as limonene, tannins, mucilages, oligomer procyanidin and traces of coumarin (2, 3).

Irritant and allergic reactions of the skin and mucous membranes have been reported. Cross-reactivity with balsam of Peru is possible (3, 4).

Among the main components of cinnamon oil tested, only cinnamic alcohol, but not cinnamaldehyde, gave an allergic reaction in our patient. Cinnamaldehyde is generally recognized as having a higher sensitization potential than cinnamic alcohol (5–8); nevertheless, according to some reports (9, 10), sensitivity to cinnamic alcohol is similarly or even more frequent than to cinnamaldehyde, because of higher exposure. Thus, the industry guidelines state that the content of cinnamic alcohol should not exceed 4%, whereas they do not restrict the use of cinnamic aldehyde (6).

It has been hypothesized that cinnamic alcohol is a “prohapten” and, owing to metabolic activation, it is transformed into the “true hapten” cinnamaldehyde in the skin (6, 7, 11).

There is a certain cross-reactivity between cinnamic alcohol, cinnamaldehyde and cinnamic acid, depending on skin absorption kinetics, cutaneous enzymatic metabolism and unexplained inter-individual differences (7).

Cinnamic alcohol, separately tested at 5%, is also a component of:

  • fragrance mix (at 1%), which resulted in a positive patch test in our patient
  • balsam of Peru (at 0.4%), which resulted in a negative patch test in our case. This negative reaction can probably be explained by the very low concentration of cinnamic alcohol (12).

This report, in addition to another report describing allergic contact vulvitis due to the same topical medicament as used by our patient (Kolorex® cream) (13), is an example of how the use of botanical extracts can lead to an increase in allergic reactions. In conclusion, all natural remedies must be regarded as possible allergens, which may result in emerging and not negligible dermatological problems.

The authors declare no conflict of interest.


  • García-Abujeta JL, de Larramendi CH, Berna JP, Palomino EM. Mud bath dermatitis due to cinnamon oil. Contact Derm 2005; 52: 234.
  • Wichtl M, editor. Teedrogen und Phytopharmaka. Ein Handbuch für die Praxis auf wissenschaftlicher Grundlage, fourth edition. Stuttgart: Wissenschaftliche Verlagsgesellschaft, 2002.
  • Fenaroli G, editor. Sostanze Aromatiche Naturali. HOEPLI, 1963: p. 447–456 and p. 385–388.
  • Sánchez-Pérez J, García-Díez A. Occupational allergic contact dermatitis from eugenol, oil of cinnamon and oil of cloves in a physiotherapist. Contact Derm 1999; 41: 346–347.
  • Bickers D, Calow P, Greim H, Hanifin JM, Rogers AE, Saurat JH, et al. A toxicologic and dermatologic assessment of cinnamyl alcohol, cinnamaldehyde and cinnamic acid when used as fragrance ingredients. The RIFM expert panel. Food ChemToxicol 2005; 43: 799–836.
  • Basketter DA. Skin sensitization to cinnamic alcohol: the role of skin metabolism. Acta Derm Venereol 1992; 72: 264–265.
  • Cheung C, Hotchkiss SA, Pease CK. Cinnamic compound metabolism in human skin and the role metabolism may play in determining relative sensitisation potency. J Dermatol Sci 2003; 31: 9–19.
  • Weibel H, Hansen J, Andersen KE. Cross-sensitization patterns in guinea pigs between cinnamaldehyde, cinnamyl alcohol and cinnamic acid. Acta Derm Venereol 1989; 69: 302–307.
  • Eiermann HJ, Larsen W, Maibach HI, Taylor JS. Prospective study of cosmetic reactions: 1977–1980. North American Contact Dermatitis Group. J Am Acad Dermatol 1982; 6: 909–917.
  • Malten KE, Ketel W, Nater JP, Liem DH. Reactions in selected patients to 22 fragrance materials. Contact Derm 1984; 11: 1–10.
  • Smith CK, Moore CA, Elahi EN, Smart AT, Hotchkiss SA. Human skin absorption and metabolism of the contact allergens, cinnamic aldehyde, and cinnamic alcohol. Toxicol Appl Pharmacol 2000; 168: 189–199.
  • Hausen BM. Contact allergy to Balsam of Peru. II. Patch test results in 102 patients with selected Balsam of Perù constituents. Am J Contact Dermat 2001; 12: 93–102.
  • Corazza M, Lauriola MM, Poli F, Virgili A. Contact vulvitis due to Pseudowintera Colorata in a topical herbal medicament. Acta Derm Venereol 2007; 87: 178–179.