INTRODUCTION

A 48-year-old clerical officer presented with a recurrent facialeruption. She attributed the dermatitis to a sunscreen allergybecause it seemed to occur after applying sunscreens;although, on occasions she was able to wear sunscreen withno adverse reaction.

The patient was patch and photopatch tested. She had theEuropean standard series (Chemotechnique) applied, as wellas additional series of perfumes and flavourings; plants andwoods; tars and balsams; and sunscreens. Photopatch testingwas performed using 5 J applied at 48 hours to a duplicateseries of sunscreens and a photo-allergen series.

She had positive reactions to nickel, fragrance mix andlichen acid mix, at both 48 hours and 96 hours. Photopatchtests were negative. Testing to the individual ingredients of thefragrance mix and lichen acid mix demonstrated a 21 reac-tion to oak moss and usnic acid at both 48 hours and 96 hoursand a 1/– reaction to atranorin at 96 hours.

She was unaware of exposure to lichens in the garden. Shedid, however, admit to regular use of fragrances which, on

reflection, matched her history of dermatitis. Unfortunately,we were unable to determine the constituents of herfragrances, but avoidance led to clinical resolution. Ninemonths later she had an acute vesicular flare affecting the faceand hands following an afternoon in the garden. She had notused any fragrances but, on this occasion, was aware of expo-sure to lichens growing on several shrubs.

DISCUSSION

Lichens are dual organisms composed of a symbioticrelationship between an alga and a fungus.1 The fungus,usually an Ascomycete, provides the plant its shape, and the alga provides the ability to photosynthesize. Since the 16th century, members of the families Cladoniaceae,Stictaceae, Parmeliaceae and Usneaceae have been used as raw materials in the perfume and cosmetic industries. Asmanufacturing techniques have improved, lichen extracts have been combined into toilet powders and scented sachets.Today, the principal species still used in perfumery are Evernia prunastri (Oak moss), E. furfuracea and severalRamalinae spp. The allergens in lichens include atranorin,usnic acid, and evernic acid.2,3

Most occupational contact dermatitis to lichens occurs in forestry workers who come into contact with lichensgrowing on the bark of trees.4 Another group of workers prone to occupational dermatitis are the ‘lichen pickers’ whoharvest Cladonia stellaris which is used in Christmasdecorations, flower arrangements, toy trees in model railway layouts and other products.5 Non-occupational contact with lichens includes carrying firewood, childrenclimbing trees or arranging Christmas decorations made from lichens.

In today’s society, however, the most common contact with lichens is through exposure to perfumes containing oak moss, derived from Evernia prunastri and Pseudoeverniafurfuracea.6,7 Aromatic lipids from these lichens are extractedwith a volatile hydrocarbon organic solvent. Once dried, thesecompounds are widely used in the cosmetic industry. Oakmoss contains a number of lichen acids, including usnic acid. A number of studies suggest that oak moss is the mainallergen of fragrance mix.8

Fortunately, occupational exposure to lichens is fairlylimited, so prior sensitization to lichen chemicals fromcontact with fragrances is unlikely to be a significant clinical problem. However, exposure to lichens in the garden may be of clinical relevance in fragrance-allergic

Australasian Journal of Dermatology (2000) 41, 50–51

VIGNETTE IN CONTACT DERMATOLOGY

Allergy to lichen acids in a fragrance

Marius Rademaker

Contact Dermatitis Clinic, Health Waikato, Hamilton, New Zealand

SUMMARY

A 48-year-old clerical officer with a recurrent facialeruption had positive patch test reactions to nickel, fragrance mix and lichen acid mix. On testing to indi-vidual ingredients of fragrance mix and lichen acidmix, she had 2+ reactions to oak moss, which is thoughtto be the main allergen in fragrance mix, and to usnicacid, which is one of a number of lichen acids com-prising oak moss. Avoidance of fragrance use resultedin clearing of the eruption but, subsequently, an acutevesicular flare on her face and hands occurred afterexposure to lichen on garden shrubs.

Key words: allergic contact dermatitis, oak moss,patch tests, usnic acid.

Correspondence: Dr Marius Rademaker, Consultant Dermatologist,Contact Dermatitis Clinic, Health Waikato, Hamilton, New Zealand.Email: Rademakm@hwl.co.nz

Marius Rademaker, FRACP.Manuscripts for this section should be submitted to Dr Marius

Rademaker.

Allergy to lichen acids in fragrance 51

individuals. This was the case in the patient described in this report.

REFERENCES

1. Ahmadjian V. A guide to the algae occurring as lichen symbionts:Isolation, culture cultural physiology and identification.Phycologia 1967; 6: 127–40.

2. Mitchell JC, Maibach HI. Sensitizing capacity of usnic acidderived from lichenized fungi. Acta Derm. Venereol. 1969; 49:498–500.

3. Thune PO, Solberg YJ. Photosensitivity and allergy to aromaticlichen acids, Compositae oleoresins and other plant substances.Contact Dermatitis 1980; 6: 64–71.

4. Mitchell JC. Allergy to lichens. Arch. Dermatol. 1965; 92: 142–6.

5. Salo H, Hannuksela M, Hausen B. Lichen picker’s dermatitis(Cladonia alpestris (L.) Rab.). Contact Dermatitis 1981; 7: 9–13.

6. Dahlquist I, Fregert S. Contact allergy to atranorin in lichens andperfumes. Contact Dermatitis 1980; 6: 111–19.

7. Thune P, Solberg Y, McFadden N, Staerfelt F, Sandberg M.Perfume allergy due to oak moss and other lichens. ContactDermatitis 1982; 8: 396–400.

8. Frosch PJ, Pilz B, Andersen KE et al. Patch testing with fragrances:Results of a multicenter study of the European Environmental and Contact Dermatitis Research Group with 48 frequently used constituents of perfumes. Contact Dermatitis 1995; 33:333–42.