From 1982 to 1999 I was a member of the Contact Dermatoses Committee of the Dutch Society for Dermatology and Venereology (NVDV). In 1983 I was appointed secretary and a year later chairman, a position I continued to hold until 1999, when I left this gremium. The Committee originated from the 'Werkgroep Arbeidsdermatologie', which was formed by the three founders of the subspecialty of dermatoallergology in the Netherlands: Prof. dr. K.E. Malten (Nijmegen), Dr W.G. van Ketel (VU Amsterdam) and Dr J.P. Nater (Groningen). In 1981, the working group was transformed into the Contact Dermatoses Committee. At the suggestion of the Board of the NVDV, the Committee was expanded to include representatives from all academic centers and dermatologists working in non-academic hospitals. I was invited to join the Committee on the recommendation of Johan Nater. In the chapter on my PhD research and dissertation, I described how important the Committee members were to that research. I have carried out a lot of research in varying compositions with one or more of the committee members, which has resulted in research data for my dissertation and a large number of publications, both of the research data and articles derived from it.

Derk Bruynzeel described this period in his contribution to my Liber Amicorum as follows: 'Anton was asked to become a member of the committee. The research was given a new impetus by his presence and activities and would eventually lead to the research on which he would receive his doctorate. A period of great activity began. Anton's relentless energy has resulted in numerous articles and case studies, a favorite feature in Contact Dermatitis. Publications, nearly always related to the topic of cosmetics and cosmetic ingredients. The subject of cosmetics gradually also became the subject of joint research by the Committee. Doing research together, at different locations, with people with different insights and differently functioning clinics is not easy. Setting up, agreeing and finally actually starting the investigation took a lot of time, persuasion and explanation, especially later when the Committee was expanded. But Anton is tall and persuasive, and that undoubtedly helped to determine the course of action. He led the Committee's investigation with great enthousiasm, first as secretary and later as chairman. The Committee entered a period of unprecedented activity and became an important committee within the Dutch Society for Dermatology and Venereology with a visible scientific output. The highlight was Anton's PhD in 1988 in Groningen with Professor Nater, head of the dermatology department of the Groningen university hospital'.

In 1999 I left the Committee of my own accord. I was probably already preparing in my mind for the termination of my practice activities. The publications that I have written together with one or more members of the Contact Dermatoses Committee, which are directly (research data) or indirectly (review articles, letters to the editor, etc.) related to the PhD research, are listed below.

Eczema of the lips is called cheilitis in dermatology. There are several forms of cheilitis, including allergic contact dermatitis (ACD). The left picture shows ACD. This image is more than a century old. In the 1950s and 1960s, bright red lips were in vogue (think Marilyn Monroe). The bright red colors often contained eosin and -derivatives, which sometimes caused contact allergy. The yellow color and the exudation on the lips suggest that a secondary bacterial infection has occurred with Staphylococcus aureus (aureus = golden). Other causes of allergic cheilitis include lip cosmetics such as balm and ointment and toothpaste. Cheilitis can also be based on atopic eczema. The lips are then often very dry and have small cracks in the skin (rhagades). In these cases, moistening the lips a little with the tongue feels good. But when done frequently and long-term, irritation of the lips by saliva causes another form of eczema: 'lip licking dermatitis'. Sometimes no cause for cheilitis can be found, as in the patient on the right.

• De Groot AC, Liem DH, Nater JP, van Ketel WG. Patch tests with fragrance materials and preservatives. Contact Dermatitis 1985;12:87-92
• De Groot AC, Weijland JW, Bos JD, Jagtman BA. Contact allergy to preservatives (1). Contact Dermatitis 1986;14:120-122
• De Groot AC, Bos JD, Jagtman BA, Bruijnzeel DP, van Joost Th, Weijland JW. Contact allergy to preservatives (II). Contact Dermatitis 1986;15:218-222
• De Groot AC, Nater JP, Van der Lende R, Rijcken B. Een retrospectief bevolkingsonderzoek naar bijwerkingen van cosmetica. Ned Tijdschr Geneeskd 1987;131:863-865
• De Groot AC, Coenraads PJ, Nater JP. Adverse effects of cosmetics: a survey among clients of beauticians. J Appl Cosmetol 1987;5:104
• De Groot AC, Beverdam EGA, Tjong Ayong C, Coenraads PJ, Nater JP. The role of contact allergy in the spectrum of adverse effects caused by cosmetics and toiletries. Contact Dermatitis 1988;19:195-201
• De Groot AC, Nater JP, van der Lende R, Rijcken B. Adverse effects of cosmetics and toiletries: a retrospective study in the general population. Int J Cosm Science 1988;9:255-259
• De Groot AC, Bruijnzeel DP, Bos JD, van der Meeren HLM, van Joost Th, Jagtman BA, Weijland JW. The allergens in cosmetics. Arch Dermatol 1988;124:1525-1529
• De Groot AC, Bos JD, Liem DH. Contact allergy to bornelone. Contact Dermatitis 1984;10:45-46
• De Groot AC, van der Meeren HLM, Weijland JW. Contact allergy to avocado oil in a sunscreen. Contact Dermatitis 1987;16:108-109
• De Groot AC, De Wit FS, Bos JD, Weijland JW. Contact allergy to cocamide DEA and lauramide DEA in shampoos. Contact Dermatitis 1987;16:117-118
• De Groot AC, van der Walle HB, Jagtman BA, Weijland JW. Contact allergy to 4-isopropyl- dibenzoylmethane and 3-(4'-methylbenzylidene)-camphor in the sunscreen Eusolex 8021. Contact Dermatitis 1987;16:249-254
• Bruijnzeel DP, de Groot AC, Weijland JW. Contact dermatitis to lauryl pyridinium chloride and benzoxonium chloride. Contact Dermatitis 1987;17:41-42
• De Groot AC, Bruijnzeel DP, Jagtman BA, Weijland JW. Contact allergy to diazolidinyl urea (Germall II). Contact Dermatitis 1988;18:202-205
• De Groot AC, van der Meeren HLM, Weijland JW. Cosmetic allergy from stearic acid and glyceryl stearate. Contact Dermatitis 1988;19:77-78
• De Groot AC, Bruijnzeel DP, van Joost Th, Weijland JW. Cosmetic allergy from myristyl alcohol. Contact Dermatitis 1988;19:76-77
• De Groot AC, Liem DH, Nater JP, van Ketel WG. Patch tests with fragrance materials and preservatives. Contact Dermatitis 1985;12:87-92
• De Groot AC, Bos JD. Preservatives in the European standard series for epicutaneous testing. Brit J Dermatol 1987;116:289-292
• De Groot AC, Bruijnzeel DP. Kathon CG. Contact Dermatitis 1987;17:189-190
• De Groot AC. Kathon CG: risk of sensitization. J Appl Cosmetol 1987;5:70
• De Groot AC, Bos JD, Bruijnzeel DP. Study of the interaction of Kathon CG- Germall II in hydrophilic creams. Int J Cosm Science 1987;9:249-250
• De Groot AC, Bruijnzeel DP, Van der Schroeff JG, Bos JD. Routine testing with the preservative system Kathon CG. Int J Cosm Science 1988;10:47-51
• De Groot AC, Jagtman BA, van der Meeren HLM, Bruijnzeel DP, Bos JD, den Hengst CW, Weijland JW. Cross-reaction pattern of the cationic emulsifier oleamidopropyl dimethylamine. Contact Dermatitis 1988;19:284-289

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