1. General data

1.1 Identity of the ingredient : Oakmoss / Treemoss extracts. Oakmoss extracts are derived from the lichen, Evernia Prunastri (L.) Arch. (Usneaceae), growing primarily on oak trees. Treemoss extracts are derived from a mixture of lichens, mainly Evernia Furfuracea (L.) Arch. (Usneaceae) growing on Pinus species.

1.2 Cas no : 90028-68-5/90028-67-4

1.3 Use : Fragrance ingredients

2. Terms of reference

2.1. Context of the question

Under the current legislation, fragrance materials do not fall under all requirements of Directive 76/768/EEC on cosmetic products. Whilst Article 2 of Directive 76/768/EEC applies to all products, few individual ingredients are included in the provisions of the Directive. Currently, the industry is self-regulated through the code of practice of the International Fragrance Association (IFRA).

Following the 6 ^th Amendment (93/35/EEC) a certificate of conformity must be provided to certify that the compound conforms to IFRA guidelines and the Cosmetic Directive. The 6 ^th amendment also provided for the labelling of ingredients on cosmetic products. However, it is not a requirement to label fragrance constituents on the packaging of cosmetic products, current legislation requires only the word parfum.

In response to growing concern over the issue, the Commission was asked for positive actions to legislative measures on fragrance materials.

2.2. Request to the SCCNFP

The SCCNFP has been asked to respond to the following questions :

i) Does the SCCNFP agree to the inclusion of all IFRA restricted materials in the Annex III (List of substances which cosmetic products must not contain except subject to restrictions and conditions laid down)? Are the permitted levels recommended by IFRA suitable for use in the Cosmetic Directive 76/768/EEC?

ii) Does the SCCNFP agree that all materials that IFRA recommend should not be used as fragrance compounds are included in Annex II (List of substances which must not form part of the composition of cosmetic products)?

iii) It is proposed that all known fragrance allergens are labelled on cosmetics if used in the products. Does the SCCNFP agree to this proposal? If so :

- Which chemicals fall under this classification?

- Is there a maximum concentration of each chemical permissible without the requirement for labelling?

iv) Restrictions are proposed for the 3 most common fragrance allergens (cinnamic aldehyde, isoeugenol, hydroxycitronellal). Does the SCCNFP agree to restriction on the use of common fragrance allergens (Annex III listing)? If so :

- Which fragrance materials should be subject to restrictions?

- What are the conditions for restrictions (maximum concentration, field of applications, etc.)?

Obviously, in response to each of the questions listed above, a scientific justification will be necessary.

2.3. Strategy of the SCCNFP

The SCCNFP has considered that this mandate can be usefully divided into two sections (Interim position on fragrance allergy, document no. SCCNFP/0202/99 adopted by the SCCNFP during the 8 ^th plenary meeting of 23 June 99) :

1. Identification of those fragrance ingredients, which are of concern as allergens for the consumer. Recommendations on informing the consumer of the presence of important allergens to permit the consumer with a known fragrance allergy a means to avoid contact with an allergen. An opinion as to whether such identification can be related to concentrations present in a product when elicitation levels are known.

2. An opinion on the adoption of industry prohibited substances into Annex 2 and adoption of industry restricted substances into Annex 3. Considerations as to whether the concentration limits or other restrictions suggested by industry can be supported or need to be changed if there is such inclusion in Annex 3. Whether there are additional substances which could be subject to inclusion in an Annex.

An opinion related to the first section has been adopted by the SCCNFP during the 10 ^th plenary meeting of 8. December 1999 (doc.no. SCCNFP/0017/98 final) that :

- Information should be provided to consumers about the known presence in cosmetic products of fragrance ingredients with a well-recognised potential to cause contact allergy.

- A list of 13 chemicals that were the most frequently reported and well-recognised consumer allergens and a list of 11 chemicals less frequently reported and thus less well-documented as consumer allergens were provided

- Natural materials such as oakmoss should be considered in a separate document.

Further an opinion related to the second section has been adopted by the SCCNFP during the 12 ^th plenary meeting of 3. May 2000 (doc. no. SCCNFP/0320/00, final) and consists of:

- an initial list of perfumery materials which must not form part of fragrance compounds used in cosmetic products.

This opinion relates to the first section and concerns the natural ingredients: oakmoss/treemoss extracts.

3. Opinion of the SCCNFP

On review of the information presently available, it is the opinion of the SCCNFP that oakmoss/treemoss extracts, present in cosmetic products, have a well-recognised potential to cause allergic reactions in the consumer as fragrance ingredients.

In accordance with the opinion of the SCCNFP adopted 8. December 1999, information should be provided to the consumer regarding the presence of oakmoss/treemoss extracts in cosmetic products. This is required to improve the protection of the consumer by ensuring that the correct diagnosis of contact allergy to well-recognised allergens can be made without undue delay and by providing information that will help the consumer to avoid specific substances that they may not tolerate.

Full Opinion

1. General data

1.1 Identity of the ingredient : Oakmoss / Treemoss extracts

1.2 Cas no : 90028-68-5/90028-67-4 Oakmoss extracts are derived from the lichen, Evernia Prunastri (L.) Arch. (Usneaceae), growing primarily on oak trees (1). Treemoss extracts are derived from a mixture of lichens, mainly Evernia Furfuracea (L.) Arch. (Usneaceae) growing on Pinus species (2).

1.3 Use : Fragrance ingredients

2. Terms of reference

2.1 Context of the question

Under the current legislation, fragrance materials do not fall under all requirements of Directive 76/768/EEC on cosmetic products. Whilst Article 2 of Directive 76/768/EEC applies to all products, few individual ingredients are included in the provisions of the Directive. Currently, the industry is self-regulated through the code of practice of the International Fragrance Association (IFRA).

Following the 6 ^th Amendment (93/35/EEC) a certificate of conformity must be provided to certify that the compound conforms to IFRA guidelines and the Cosmetic Directive. The 6 ^th amendment also provided for the labelling of ingredients on cosmetic products. However, it is not a requirement to label fragrance constituents on the packaging of cosmetic products, current legislation requires only the word parfum.

In response to growing concern over the issue, the Commission was asked for positive actions to legislative measures on fragrance materials.

2.2 Request to the SCCNFP

The SCCNFP has been asked to respond to the following questions :

i) Does the SCCNFP agree to the inclusion of all IFRA restricted materials in the Annex III (List of substances which cosmetic products must not contain except subject to restrictions and conditions laid down)? Are the permitted levels recommended by IFRA suitable for use in the Cosmetic Directive 76/768/EEC?

ii) Does the SCCNFP agree that all materials that IFRA recommend should not be used as fragrance compounds are included in Annex II (List of substances which must not form part of the composition of cosmetic products)?

ii) It is proposed that all known fragrance allergens are labelled on cosmetics if used in the products. Does the SCCNFP agree to this proposal? If so :

- Which chemicals fall under this classification?

- Is there a maximum concentration of each chemical permissible without the requirement for labelling ?

iv) Restrictions are proposed for the 3 most common fragrance allergens (cinnamic aldehyde, isoeugenol, hydroxycitronellal). Does the SCCNFP agree to restriction on the use of common fragrance allergens (Annex III listing)? If so :

- Which fragrance materials should be subject to restrictions?

- What are the conditions for restrictions (maximum concentration, field of applications, etc.)?

Obviously, in response to each of the questions listed above, a scientific justification will be necessary.

2.4 Strategy of the SCCNFP

The SCCNFP has considered that this mandate can be usefully divided into two sections (Interim position on fragrance allergy, document no. SCCNFP/0202/99 adopted by the SCCNFP during the 8 ^th plenary meeting of 23 June 99) :

1. Identification of those fragrance ingredients, which are of concern as allergens for the consumer. Recommendations on informing the consumer of the presence of important allergens to permit the consumer with a known fragrance allergy a means to avoid contact with an allergen. An opinion as to whether such identification can be related to concentrations present in a product when elicitation levels are known.

2. An opinion on the adoption of industry prohibited substances into Annex 2 and adoption of industry restricted substances into Annex 3. Considerations as to whether the concentration limits or other restrictions suggested by industry can be supported or need to be changed if there is such inclusion in Annex 3. Whether there are additional substances which could be subject to inclusion in an Annex.

An opinion related to the first section has been adopted by the SCCNFP during the 10 ^th plenary meeting of 8. December 1999 (doc.no. SCCNFP/0017/98 final) that:

- Information should be provided to consumers about the known presence in cosmetic products of fragrance ingredients with a well-recognised potential to cause contact allergy.

- A list of 13 chemicals that were the most frequently reported and well-recognised consumer allergens and a list of 11 chemicals less frequently reported and thus less well-documented as consumer allergens were provided

- Natural materials such as oak moss should be considered in a separate document.

Further an opinion related to the second section has been adopted by the SCCNFP during the 12 ^th plenary meeting of 3. May 2000 (doc. no. SCCNFP/0320/00, final) and consists of:

- an initial list of perfumery materials which must not form part of fragrance compounds used in cosmetic products.

This opinion relates to the first section and concerns the natural ingredients: oakmoss/treemoss extracts.

3. Evaluation of allergenic properties

3.1Botanical sources and methods ofproduction

True oakmoss extracts are derived from Evernia Prunastri (L.) Arch. (Usneaceae), a lichen growing primarily on oak trees. The lichen is collected all over central and southern Europe, and also in Morocco and Algeria. Very few commercially available oakmoss extracts have been 'true and genuine': There is hardly any other perfume material that has so frequently been 'doctored up', 'compounded', 'bouquetted' as oakmoss extracts. Most oakmoss products have, in reality, been mixtures of oakmoss and treemoss extracts (1). Recently a recommendation has been issued by The International Fragrance Association that oakmoss extracts used in perfumes must not contain treemoss extracts (c.f. section 4.0).

Treemoss is derived from a mixture of lichens, mainly Evernia Furfuracea (L.) Ach. (Usneaceae), growing on Pinus species (2) in forests in central and southern Europe. The admixture of treemoss to oakmoss may occur already at the point of harvesting (2,3).

Extracts are produced from the botanical material as :

- Concrètes, by extraction.

- Absolutes, by alcohol extraction of concrètes.

- Absolute oils, by vacuumdistillation of the absolute

- Resins, so-called, are generally produced from washed residues which are insoluble in alcohol during the production of the absolute. The waxy residue is 'touched up' by the addition of various natural and synthetic perfume materials and solvents.

- Resinoids, so-called, are produced by hot alcohol extraction of the botanical material. The residue is usually touched up with other perfume materials.

The absolutes are the most popular form of oakmoss extract (1).

3.2 Constituents - possible allergens.

Atranorin (4,5), evernic acid, fumarprotocetraric acid, stictic acid (6-9) and usnic acid (5,6) are regarded as some of the responsible sensitisers in oakmoss extracts, based on experience from patch testing patients.

A chemical analysis regarding the aldehyde content in a commercial sample of oakmoss absolute showed the presence of : Ethyl hematommate, ethyl chlorohematommate, atranorins, atranol and chloroatranol (10).

A recent study showed that two commercial samples of treemoss absolute contained a mixture of resin acids, accounting for 11.4% (wt/wt) and 8.1% (wt/wt), respectively (3) The major components were dehydroabietic acid together with abietic acid and its isomers. Moreover, the presence of 7-oxo-dehydroabietic acid an oxidation product of dehydroabietic acid was detected in concentrations of 1.6% (wt/wt) and 1.1% (wt/wt) in the two samples. The source of resin acids in treemoss extracts is probably the bark of the Pinus species, colonised by E. Furfuracea (3).

Evernic acid is not present in treemoss extracts according to Actander, 1960 (2).

3.3 Animal studies

A guinea pig maximisation test, GPMT, using groups of eight animals induced with 5.0% e.c./20.0% i.d. concentration of a commercially available oak moss absolute, showed that at challenge with 0.1% oakmoss absolute none were sensitised, 2/8 animals challenged with 0.3% and 5/8 challenged with 1.0% oakmoss absolute were sensitised. At rechallenge two of seven reacted in the two groups using the highest concentration (10).

A series of guinea pig sensitisation studies were carried out by the Research Institute for Fragrance Materials (RIFM). Because of the variations of oakmoss preparations used by the industry nine absolutes and three concretes were studied as authentic samples. No significant differences in sensitisation potential between the samples were seen and two absolutes from this group were then chosen for a series of Human Repeated Insult Patch Tests (HRIPT). Both absolutes gave positive results, see below (11).

3.4 Experimental induction studies in healthy humans volunteers.

A modified HRIPT (Draize) was performed with a 9-24h occluded application in 3 weeks. Induction concentration: 5% commercially available oakmoss absolute in a mixture of acetone/ethanol (1:1) and challenge with 0.5%, 2.0% and 5.0% oakmoss absolute. 47 females and 7 males were tested. In total 7 out of 53 (13%) panellists were sensitised to oakmoss absolute by this procedure (10).

Two oak moss absolutes obtained from industry as authentic samples gave positive results in HRIPT at 5% in a 3:1 mixture of ethanol/diethyl phthalate. No sensitisation was seen in 103 volunteers tested with 0.6% in the same solvent. No further details are given (11).

In a HRIPT using 1.2% oakmoss extract for induction 0/47 volunteers reacted in one test and 1/48 volunteers in another test. No further details are given (12).

In studies on treemoss there was no reaction at 0.6% in ethanol/DEP and 2/50 (4%) induced sensitisation reactions were seen at 1.2%. The two sensitised volunteers also reacted to oakmoss.

No further details are given (12).

3.5 Dermatological data from sensitised individuals

3.5.1 Consecutive eczema patients

Since 1979 oakmoss absolute has been incorporated in the fragrance mix as one of 8 ingredients used routinely for the detection of contact allergy to fragrances (13).

The fragrance mix is used for routine investigations of patients with contact eczema in dermatological clinics in Europe (14). In case an allergic reaction to the mixture is found the patient is retested with the individual ingredients of the mixture if practically possible. Data on

oakmoss extract sensitivity obtained this way has been published.

Oakmoss absolute account for most of the reactions to the fragrance mix (table 1). It is regarded as one of the principle allergens in contact sensitivity to perfumes (6).

Table 1: Consecutive patients tested with FM and subsequently, if possible, with its ingredients

*) Tested at 5%. Rank: Rank according to frequency compared with the other seven ingredients of the Fragrance Mix. Abs. absolute.

In a 17 years study in United Kingdom, oakmoss absolute remained the most common overall allergen throughout the study, positive in 38.3% of females and 35.6% of males who were tested to the constituents of the fragrance mix. During the period of study the incidence of positive tests to oak moss increased by 5% yearly, p=0.001 (21).

3.5.2 Subgroups of patients tested

55 patients were identified with sensitivity to different brands of perfumes, after-shave lotions by repeated questioning and/or testing. 16 patients also had a definite history of contact allergy to plants following direct contact. The patients were tested with plant extracts and isolated plant compounds. All 55 had a positive reaction to a lichen mixture consisting of hypogymnia tubulosa, H. Physodes, pamelia sulcata, Pseudovernia furfuracea and Physcia tenella. 35 reacted to oakmoss absolute 2%, atranorin was positive in 21 and evernic acid in 12. Reactions to various other lichen acids and extracts were found (22).

167 patients with suspected or verified contact allergy to fragrance ingredients were tested with a screening series of allergens. 13.2 % showed an allergic reaction to oakmoss absolute 5% (supplied by Takasago Perfume Company, Japan) (23).

179 patients suspect of contact allergy to cosmetics were tested with a screening series of fragrance ingredients, oakmoss absolute was tested at 10% in petrolatum and 21(11.7%) gave a positive reaction (24)

3.5.3 Case reports

A hairdresser developed contact eczema on the hands and face. She had a perm with the same solution as used at work and developed a dermatitis on the scalp the same evening. She was tested with seven components of the perming solution obtained from the manufacturer. She reacted to one component containing oak moss and was also positive when tested with oakmoss separately. She was not positive to any other ingredients of the perm solution (25).

An allergic contact dermatitis in a women was found to be due to oak moss in her husband's after-shave lotion. The patient did not use any perfumes herself. At patch testing she reacted to her husbands after shave and oakmoss 5% in petrolatum. The after-shave contained 3% oakmoss (26).

Seven patients among 2000 tested were proven to have allergy to oakmoss absolute. Four patients had themselves suspected allergy to perfumes, in two it was suspected by the doctor and in one it was accidentally detected. Patch tests with patients own perfumes were positive in three cases, whilst not being performed in the others. The oakmoss absolute used for testing was supplied by an international fragrance manufacturer. Patients were tested with mixed lichens and a number of aromatic compounds. Positive reactions were seen to : atranorin (4 patients), usnic acid (5 patients), evernic acid (4 patients), physodic/physodalic acid (3 patients), diffractaic acid (1 patient) (27).

A case of oak moss and atranorin allergy is reported. Source of sensitisation was unknown (28).

3.6 Source of sensitisation

Among 31 patients allergic to oak moss, in 20 cases the origin of sensitisation was contact with perfumes, in 7 cases with lichen and in 4 unknown (7).

14 oak moss sensitised individuals were identified by patch testing with an acetone extract of oak moss, evernia prunastri (7% in pet.). In 12 cases a history of rash by perfume or after-shave contact was found. It was concluded that in oak moss sensitivity perfume contact is the commonest cause, but a history of lichen exposure should not be ignored (5)

In Norway (1982) allergy to oak moss and different lichen substances seems to be much more common than allergy to Musk ambrette which was a well-known sensitiser and photosensitiser at the time of study. A total of 23 patients had been identified with proven allergies to lichens. The source of these allergies could apparently be found in perfumes and in direct contact with lichens. It is the authors opinion that cosmetics containing lichen extracts are much more important sources of contact allergy than lichens encountered in nature (27).

Probably the most important source of contact with lichens and compositae compounds is cosmetics, which frequently contain fragrances such as oak moss and compositae extracts (22).

3.7 Photo-sensitisation/persistent light reactivity

Photo-contact dermatitis was demonstrated to a given eau de cologne, oak moss, atranorin and evernic acid in a man who worked in an orchard, but first developed a dermatitis with Berloque type distribution after daily application of the eau-de cologne. Testing of the eau de cologne without oak moss was negative. Ten lichen plants were also tested. All negative (29). The patient was re-tested years later and the photo-allergy to oak moss, atranorin and evernic acid was confirmed. The man had stopped using the eau-de cologne and the dermatitis had disappeared although he was working in the open air exposed to sun (30).

55 patients with sensitivity to different brands of perfumes, deodorants, after-shave lotions verified by questioning and/or testing was photo-patch tested with purified lichen extracts and compositae extracts as well as some isolated lichen acids. Patients also underwent non-irradiated patch testing. Photo-allergic reactions were induced by atranorin and evernic acid in two patients. It is not clear how the remaining patients reacted (22).

In one study, occlusion for longer periods caused stronger reactions than irradiation of the patch test in all patients with photosensitivity, indicating that the mechanism of contact allergy has a stronger role than photo-allergy in precipitating lichen-induced allergic skin responses (27).

Persistent light sensitivity

Chronic photosensitive dermatitis occurs almost exclusively in elderly men and is characterised by an extreme sensitivity to UV light. the sensitivity spectrum sometimes extends into visible light, making daily social life almost unbearable. 18 men with persistent light reactivity was subjected to extensive photo-testing. 17 patients showed contact or photo-contact reactions. Contact allergy to oak moss constituents and different lichen compounds was twice as common as allergy to Compositae oleoresins (31).

4.0 Code of Practice (IFRA)

In 1992 IFRA Code of Practice recommended that oakmoss and treemoss extracts (e.g. absolute, resinoid, concrete, etc.) obtained from Evernia and Usnea species should not be used, individually or in combination, such that the level in consumer products exceeded 0.6%. This was equivalent to 3% in a fragrance compound used at 20% in the consumer product (12)

The recommendation was made in order to promote good manufacturing practice (GMP) for the use of oak moss and tree moss extracts as fragrance ingredients. It was based on RIFM data on the sensitising potential of oakmoss and treemoss extracts and their cross reactivity (12). The guideline was amended again in 1998, so that the total concentration of oakmoss plus treemoss extracts now was restricted to 0.1% in consumer products. The change in recommendations was based on unpublished data from HRIPTs from 1988 to 1990 (12). Since April 2000 IFRA has recommended that oakmoss extracts used in perfume compounds must not contain treemoss. This is based on the findings that oxidation products of resin acids, present in treemoss extracts (3), contribute to the sensitising potential (32).

5.0 Summary

Oakmoss and treemoss are lichens. Extracts are made from the botanical materials and used as fragrance ingredients. Most oakmoss products have been mixtures of oak and treemoss extracts. Oakmoss may also have been contaminated by treemoss at the time of harvesting. Recently a recommendation has been issued by the International Fragrance Association that oakmoss extracts used in perfumes must not contain treemoss extracts. Otherwise oakmoss and treemoss extracts are treated as one ingredient by the International Fragrance Association in their code of practice. The allergenic potential of various commercial samples of oakmoss/treemoss extracts have been documented in animal assays and in experimental induction studies in humans.

Commercial qualities of oakmoss extracts have been documented as one of the most well-recognised fragrance allergens in the consumer by patch testing. On a European level contact allergy to oakmoss extract has been detected in 2.2% to 2.6% of consecutively patch tested eczema patients.

In patients with known or suspected sensitivity to fragrance ingredients, allergic reactions to oak moss extract have been found in 11.7%-13.2% by patch testing.

The main allergen(s) in oakmoss/treemoss extracts have not been determined but several candidates exist.

6.0 Opinion of the SCCNFP

On review of the information presently available, it is the opinion of the SCCNFP that oakmoss/treemoss extracts, present in cosmetic products, have a well-recognised potential to cause allergic reactions in the consumer as fragrance ingredients.

In accordance with the opinion of the SCCNFP adopted 8 December 1999, information should be provided to the consumer regarding the presence of oakmoss/treemoss extracts in cosmetic products. This is required to improve the protection of the consumer by ensuring that the correct diagnosis of contact allergy to well-recognised allergens can be made without undue delay and by providing information that will help the consumer to avoid specific substances that they may not tolerate.

7.0 References

1. Actander S. Oak Moss. Perfume and Flavor Materials of Natural Origin. Elisabeth NJ (USA) 1960: 446-46.

2. Actander S. Treemoss absolute. Perfume and Flavor Materials of Natural Origin. Elisabeth NJ (USA) 1960: 627-630

3. Lepoittevin JP, Meschkat E, Huygens S, Goossens A. Presence of resin acids in 'oak moss' patch test material: a source of misdiagnosis. J. Invest Dermatol 2000;115:129-30.

4. Dahlquist I, Fregert S. Atranorin and oak moss contact allergy. Contact Dermatitis 1981:7:168-69

5. Fregert S, Dahlquist I. Patch testing with oakmoss extract. Contact Dermatitis 1983:9:227.

6. Goncalo S, Cabral F, Goncalo M. Contact sensitivity to oak moss. Contact Dermatitis 1988:9:355-357.

7. Goncalo S. Contact sensitivity to lichens and compositae in frullania dermatitis. Contact Dermatitis 1987:16: 84-86

8. Thune P. Allergy to lichens with photosensitivity. Contact Dermatitis 1977:3:213-214.

9. Thune P. Photosensitivity and allergy to aromatic lichen acids. Compositae oleoresins and other plant substances. Contact Dermatitis 1980:6:81-87.

10. Ehret C, Maupetit P, Petrzilka M, Klecak G. Preparation of an oakmoss absolute with reduced allergenic potential. International Journal of Cosmetic Science 1992:14:121-130.

11. Ford RA, Api AM. An Investigation of the potential for allergic contact sensitisation of several oakmoss preparations. Contact Dermatitis 1990:23:249.

12. IFRA Code of Practice. Background of the guideline regarding oakmoss/treemoss extracts. September 1988/amended 1992 and 1998.

13. Larsen W. Perfume Dermatitis. A study of 20 patients. Arch Dermatol 1977:113:623-626.

14. Andersen KE, Burrows D, White I. Allergens from the standard series. In Textbook of Contact Dermatitis, eds. Rycroft RJG, Menné T, Frosch PJ, 2.ed. 1995: 425-27.

15. Hendriks SA, Ginkel CJW. Evaluation of the fragrance mix in the European standard series. Contact Dermatitis 1999:41:161-174.

16. De Groot, Kley AMJ, Bruynzeel DP, Meinardi MMHM, Smeek G, Joost TH, Pavel S. Frequency of false-negative reactions to the fragrance mix. Contact Dermatitis 1993:28:139-140.

17. Johansen JD, Menné T. The fragrance mix and its constituents. Contact Dermatitis 1995:32:18-23.

18. Frosch PJ, Pilz B, Burrows D et al. Testing with the fragrance mix. Is the addition of soebitan sesquioleate useful ? Contact Dermatitis 1995: 32:266-272

19. Frosch PJ, Pilz B, Andersen KE, et al. Patch testing with fragrances: results of a multicentre study of the European Environmental and Contact Dermatitis Research Group with 48 frequently used constituents of perfumes. Contact Dermatitis 1995:33:333-342.

20. Enders F, Przybilla B, Ring J. Patch testing with fragrance mix 16% and 8% and their individual constituents. Contact Dermatitis 1989:20:237-238.

21. Buckley DA et al. The frequency of fragrance allergy in a patch-test population over a 17- year period. British Journal of Dermatology 2000:142:279-283.

22. Thune P, Sandberg M. Allergy to lichen and compositae compounds in perfumes. Investigations on the sensitizing, toxic and mutagenic potential. Acta Derm venereol (Stockholm) 1987; suppl. 134:87-89.

23. Larsen W, Nakayama H, Lindberg M, Fisher T et al. Fragrance contact dermatitis: A world wide multicentre investigation (Part I). Am J Contact Dermatitis 1996:7:77-83

24. De Groot AC, Liem DH, Nater JP, Ketel WG. Patch tests with fragrance materials and preservatives. Contact Dermatitis 1985:12:87-92.

25. Kanerva L, Jolanki R, Estlander T. Hairdresser's dermatitis caused by oak moss in permanent waving solutions. Contact Dermatitis 1999:41:55-56.

26. Held JL, Ruszkowski AM, DeLeo VA. Consort contact dermatitis due to oak moss. Arch Dermatol 1988:124:261-2.

27. Thune P, Solberg Y, McFadden N, Stærfelt F, Sandberg M. Perfume allergy due to oak moss and other lichens. Contact Dermatitis 1982:8:396-400.

28. Romaguera C, Vilaplana J, Grimalt F. Contact dermatitis from oak moss. Contact Dermatitis 1991:24:224-25

29. Fernández de Corres L. Photosensitivity to oak moss. Contact Dermatitis 1986:15:118.

30. Fernández de Corres L, Munoz D, Leaniz-Barrutia I, Corrales JL. Photocontact dermatitis from oak moss. Contact Dermatitis 1983:9:528-29.

31. Thune P, Eeg-Larsen T. Contact and photocontact allergy in persistent light reactivity. Contact Dermatitis 1984:11:98-107.

32. IFRA code of practice. Oakmoss/treemoss. Amended April 2000