Fragrances (overview)

Fragrances are ubiquitously distributed. In the fragrance industry about 3000 different fragrances are processed. A perfume can consist of up to 300 or more different fragrances. The EC Cosmetics Regulation No.1223/2009 does not prescribe an exact declaration for fragrances. As a rule, fragrances are referred to as a collective term "fragrance" or perfume. An exception are the 26 allergenic fragrances which, if they exceed a certain concentration, must be named individually.

Fragrances are divided into synthetic and natural ones, the latter as balsams and extracts of plant origin or as essential or volatile essential oils of plant, animal or fossil origin.

Fragrances are among the most common contact allergens. In the epicutaneous test 2 fragrance mixes(Fragrance Mix and Fragrance Mix II) are used, with which about 70-80% of all fragrance sensitizations can be detected.

The diagnosis of a fragrance sensitization (see belowfragrance allergy) is not only complicated by the multitude of possible relevant fragrances, but also by often observed false-positive or false-negative test reactions.

In about 60% of the cases with a single positive reaction to the fragrance mix, no positive test reaction can be assigned in the testing of the individual substances. In the case of 2 positive reactions to the fragrance mixes, positive reactions can be detected in the testing of the individual substances in 70% of the cases. In the case of 3 positive reactions in fragrance mixes, positive reactions are detectable in the testing of the individual substances in > 90% of cases.

Relevant occupational exposures: Occupational allergic contact eczema caused by fragrances is rare and unusual, but casuistically described in many occupational groups. Therefore, a breakdown of the individual components is necessary when assessing a PD in occupational type IV sensitisation and positive reaction to fragrance mixtures.

Effect of an allergy: Usually "minor", in the case of multiple fragrance sensitization or clinically high sensitization to a single fragrance "moderate". The latter must be specifically justified. Indications for a corresponding clinically high degree of sensitization can be e.g. an aerogenic allergic eczema or an allergic eczema already on traces of a single fragrance.

Fragrances are very heterogeneous with regard to their allergenic potential.

Especially potent allergens are:

• Tree moss absolute, cinnamal, oak moss absolute, farnesol, hydroxycitronellal, isoeugenol, lyral, cinnamic aldehyde.

They are classified as less important allergens:

• Alpha-amyl cinnamal alcohol, benzyl cinnamate, citral, citronellol, coumarin, eugenol, geraniol, lily and cinnamal alcohol.

Rare sensitizers are:

• alpha-amyl cinnamaldehyde, aniseed alcohol, benzyl alcohol, benzyl benzoate, benzyl salicylate, linalool, limonene, methyl heptine carbonate, methyl ionone.

Obligation to declare: Since 2005, 26 common fragrances must be declared on the packaging of cosmetics if they are contained in the product at a level of more than 100 ppm (rinse-off = substances to be washed off the skin) or 10 ppm (leave-on = substances remaining on the skin) (cited by n Geier et al.)

Since 2005, according to the Cosmetics Ordinance, 26 allergenic fragrances that can be found in essential oils or in perfumes must be declared on the packaging of care and cleansing products, starting at a content of 0.001 % for products that remain on the skin ("Leave On" products) and 0.01 % for those that are removed again ("Rinse Off" products).

Epicutaneous testing: Fragrances are tested in the standard series of the German Contact Allergy Group (DKG) of the German Dermatological Society (DDG) as fragrance mix 8% in vaseline and fragrance mix II 14% in vaseline. The epicutaneous test substance of the fragrance mix is a mixture of cinnamal alcohol, cinnamaldehyde, eugenol, alpha-amyl cinnamaldehyde, hydroxycitronellal, geraniol, isoeugenol and oak moss absolute. The epicutaneous test substance of the Fragrance Mix II consists of alpha-hexyl cinnamaldehyde, citral, citronellol, coumarin, farnesol and hydroxymethylpentylcyclohexenecarboxaldehyde (Lyral).

Despite well-standardised test series, a considerable proportion of fragrance allergies can only be detected by testing the products used.

Hairdressers and health care professionals show above-average sensitisation to fragrance mixtures.

In the bakery and confectionery trades, eugenol, isoeugenol, cinnamic aldehyde, vanillin and geraniol may be relevant; workers in the cosmetics industry may be sensitized to a wide variety of fragrances.

Dental workers are at increased risk of exposure to eugenol (use in dental bases and filling materials, mouthwashes and antiseptics).

Wood-cutters disease: contact eczema against oak moss constituents, especially in hunters, road and railway workers, farmers and botanists.

Type IV sensitisation to the lime fragrance has been described in car mechanics (use in hand washing pastes, cleaning and degreasing agents).

Fragrance mix is one of the most common contact allergens in venous leg ulcer patients.

1. Diepgen TL et al. (2005) Evidence-based assessment of the effect of type IV allergies in the reduction of earning capacity - assessment of occupational skin diseases. Dermatologist 56: 207-223
2. Diepgen TL et al (2008) Assessment of the effect of allergies in the reduction of disability in the context of BK 5101: Thiurams, mercaptobenzothiazoles, dithiocarbamates, N-isopropyl-N'-phenyl-p-phenylenediamine. Dermatology at work and in the environment 56: 11-24
3. Frog PJ et al (2005) Patch testing with a new fragrance mix detects additional patients sensitive to perfumes and missed by the current fragrance mix. Contact dermatitis 52: 207-215
4. Frog PJ et al (2005) Patch testing with a new fragrance mix - reactivity to the individual constituents and chemical detection in relevant cosmetic products. Contact Dermatitis 52: 216-225
5. Vulture J (2015) Scent allergy. JDDG 13 (Suppl1) 15
6. Geier J et al (2015) Diagnosis of olfactory allergy. dermatologist 66: 674-679
7. Lim KS et al (2007) Contact sensitization in patients with chronic venous leg ulcers in Singapore. Contact Dermatitis Feb 56: 94-98
8. Skudlik C, John SM, Becker D, Dickel H, Geier J, Lessmann H, Mahler V, Rogosky E, Wagner E, Weisshaar E, Diepgen TL, for the working group "Evaluation of allergens at BK 5101" of the Arbeitsgemeinschaft für Berufs- und Umweltdermatologie in der Deutschen Dermatologischen Gesellschaft (2008) Justification for the assessment of a fragrance allergy (allergens of the fragrance mix, allergens of the fragrance mix II, lyral) within the scope of the MdE-evaluation. Justification for the evaluation of fragrance allergies (allergens of fragrance mix, allergens of fragrance mix II, Lyral) in the context of the evaluation of the reduction in earning capacity]. Dermatol Occupation Environment 56: 25-30
9. Uter W et al (2007) Patch test results with patients own perfumes, deodorants and shaving lotions: results ot the IVDK 1998 - 2002 JEAVD 21: 374-379