If I have counted correctly, between 1977 and 2022, 144 articles were published in non-Dutch scientific journals, of which I was first or sole author (n=129) or co-author (n=15). The vast majority were published in English/American periodicals, only 6 in German, including 5 in Dermatosen in Beruf und Umwelt, of which I was a member of the editorial board for several years. These were, however, published in English. Of the international journals, Contact Dermatitis, the leading journal in the field of - you guessed it - contact dermatitis (contact eczema), was my favourite journal: 99 of my articles were published in it. Another important journal was American Journal of Contact Dermatitis (as of 2002 Dermatitis), the second journal in the field of contact allergy. Especially more recent articles have appeared there, which is partly a result of my joining the 'Editorial Advisory Board' in 2013, a total of 17 publications. Two or more articles were published in Journal of the American Academy of Dermatology (n=3), British Journal of Dermatology (n=3), Lancet (n=2), International Journal of Cosmetic Science (n=2), and Clinics in Dermatology (n=2). One article was published in each of the following journals (in no particular order): British Journal of Clinical Pharmacology, Clinical and Experimental Dermatology, Archives of Dermatology, Journal of Applied Cosmetology, Dermatologic Clinics, British Medical Journal, Cosmetics & Toiletries, Urology, Drugs and Therapeutics Bulletin, Journal of Toxicology – Cutaneous and Ocular Toxicology and European Journal of Dermatology.

In The Lancet twice!

I am proud of my 2 publications in The Lancet (plus a Letter to the Editor), which is the second most important general medical scientific journal after the New England Journal of Medicine. One article was about the (in)effectiveness of minoxidil in the treatment of hair loss and the other about methyl(chloro)isothiazolinone, better known at the time as Kathon CG. I'll tell you more about that below. I must confess and acknowledge that the adoption of the articles was probably facilitated by Andrew Herxheimer being my co-author (at my request); he was well connected to the editors of the Lancet.

Period of great activity

My most active period of international publishing was between 1984 and 1988 in the context of my doctoral research: 11 articles in 1987 and 14 in 1988. The collaboration with members of the Contact Dermatoses Committee made a major contribution to this. The years that followed, 1989-1991, were still very productive with 24 publications, but after that it dropped off somewhat. In the period 1998-2002 I had only 1 publication per year in international journals. The reason is clear: I had left the Contact Dermatoses Committee in 1999 (on my own initiative, I had been chairman until my departure), there was no longer any research activity of that committee and I was already thinking about ending my practice, and would then leave dermatology behind.

Stopped for a while

From 2003 to 2008 I had no publications at all in international journals. Incidentally, I was all the more active for and in the Dutch Journal of Dermatology and Venereology, of which I had become editor-in-chief for the second time in 2001. 'Only ad interim, you know', that's how I set the condition, but it turned out to become 5 years. The reason was that the then editor-in-chief, Jan Gerrit van der Schroeff was elected Chairman of the Dutch Society for Dermatology and Venereology and no (suitable) member of the society was prepared to become editor-in-chief. Of course I couldn't let the journal, of which I had been a co-founder, go to waste. 

Started again

Writing and self-publishing my book Patch testing in 2008 changed everything. I suddenly felt like publishing again and I was able to do so, because I was now teaching interns in Groningen and I had been given access to the University's digital library through a proxy account, so I could work from my study at home. The republishing started with 13 articles on formaldehyde and formaldehyde donors in 2009 and 2010. 'I can see that you're back', my friend Ian White wrote wryly in his typically undercooled British humour. After that I devoted myself to writing review articles about, among other things, henna tattoos, propolis, octocrylene, fragrances, tea tree oil, other essential oils, balsam of Peru, limonene, linalool and allergenic ingredients in toothpastes. These articles were based on my books and case histories in the context of my work as a 'supervising dermatologist' at the CESES project. The review on Myroxylon pereirae resin (Peru balsam) already had 15 literature citations after 15 months and was one of the most downloaded and read articles in Contact dermatitis in 2019.

Below is the list of my articles in international journals. I will tell you more about some of them, including how Anton C. de Groot almost was renamed Kathon C. de Groot!

• Herxheimer A, de Groot AC. Some effects of injected hyoscine butylbromide: a versatile class experiment in human pharmacology. Brit J Clin Pharmacol 1977;4:337-342
• De Groot AC, Nater JP. Contact allergy to dithranol. Contact Dermatitis 1981;7:5-8
• De Groot AC, Nater JP, Bleumink E, de Jong MCJM. Does DNCB therapy potentiate sensitization to non-related contact allergens? Clin exp Dermatol 1981;6:139-144
• De Groot AC. Contact allergy to clindamycin. Contact Dermatitis 1982;8:428
• De Groot AC. Contact allergy to sodium fusidate. Contact Dermatitis 1982;8:429
• De Groot AC, Liem DH. Facial psoriasis caused by contact allergy to linalool and hydroxycitronellal in an aftershave. Contact Dermatitis 1983;9:230-232
• De Groot AC, Liem DH. Contact allergy to Tinuvin P. Contact Dermatitis 1983;9:324-325
• De Groot AC, Liem DH. Contact urticaria to rouge. Contact Dermatitis 1983;9:322
• De Groot AC, Bos JD, Liem DH. Contact allergy to bornelone. Contact Dermatitis 1984;10:45-46
• De Groot AC, Messerschmidt HJM. Laboratory animal allergy. Contact Dermatitis 1984;11:121-122

Oleamidopropyl dimethylamine

• De Groot AC, Liem DH. Contact allergy to oleamidopropyl dimethylamine. Contact Dermatitis 1984;11:298-301

This and some other discoveries (contact allergy to oleamidopropyl dimethylamine had not been described before) stimulated my interest in cosmetic allergy. Plans were made and in 1988 I obtained my PhD on the subject of Adverse reactions to cosmetics. Oleamidopropyl dimethylamine was a separate chapter in my dissertation. The producer of the baby body lotion contacted me and invited me to talk about the problems at a dinner at Chalet Royal in 's-Hertogenbosch. The gentlemen themselves also thought that the dinner portions were a bit on the meager side (nouveau cuisine) and a second steak for Dr. De Groot was no problem at all! It has given me many years of advisory work and a good relationship with the manufacturer…..

A few years later, in a study together with some colleagues who had also seen patients with this allergy, I investigated the cross reaction pattern of oleamidopropyl dimethylamine (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). There were often multiple reactions. The other substances similar to oleamidopropyl dimethylamine probably contain the same allergen: a common component, a substance used during production or a chemical contaminant. In retrospect, I think that some of these reactions were false-positives and were based on irritation rather than on 'real' allergy.

• De Groot AC, Conemans J, Liem DH. Contact allergy to benzoxonium chloride (Bradophen). Contact Dermatitis 1984;11:324-325

Kathon ® CG: the start of a long series of publications

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

Read all about the Kathon CG saga here including a visit from the US, a threatening letter from an American law firm, swearing and ranting in the Jaarbeurshallen in Utrecht and much more.

• 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, Bos JD. Preservatives in the European standard series for epicutaneous testing. Brit J Dermatol 1987;116:289-292
• De Groot AC. Contact allergy to cosmetics: causative ingredients. Contact Dermatitis 1987;17:26-34
• De Groot AC. Isothiazolinone preservative as important contact allergen in cosmetics. Dermatosen 1987;35:169-173
• De Groot AC, Weijland JW. Kathon CG: A review. J Am Acad Dermatol 1988;18:350-358

• De Groot AC, Barella CGJ, Conemans JMH. Risk of sensitization to Kathon CG. Contact Dermatitis 1988;19:210-211
• 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, 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, 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, Bruijnzeel DP. Kathon CG: risk of sensitization. J Appl Cosmetol 1988;6:161-168
• De Groot AC, Herxheimer A. Isothiazolinone preservative: cause of a continuing epidemic of cosmetic dermatitis. The Lancet 1989;i:314-316

• De Groot AC. Methylisothiazolinone/methylchloroisothiazolinone (Kathon CG) allergy: an updated review. Amer J Contact Dermatitis 1990;1:151-156
• De Groot AC. Water versus petrolatum for patch testing methylisothiazolinone + methylchloroisothiazolinone. Contact Dermatitis 1990;23:300-301
• De Groot AC. Kontaktallergie voor een "nieuw" conserveermiddel in cosmetica: Kathon CG. Nieuwsbrief Contactdermatologie 1986;23:368-376
• De Groot AC. Kathon CG: onderzoeksresultaten van de Commissie Contactdermatosen, en praktische informatie voor de patient. Bulletin Contactdermatosen 1989:3:77-92
• De Groot AC, van Ulsen J, Weijland JW. Allergisch contacteczeem rond de anus met dyshidrotisch eczeem van de handen door Kathon CG in vochtige toiletdoekjes. Ned Tijdschr Geneeskd 1991;135:1048-1049
• De Groot AC. Cosmetica die geen methyl(chloor)isothiazolinon (Kathon CG) bevatten. Ned Tijdschr Derm Venereol 1992;2:142-146

Up to here publications on Kathon CG

• De Groot AC, Weijland JW, Bos JD, Jagtman BA. Contact allergy to preservatives (1). Contact Dermatitis 1986;14:120-122
• De Groot AC, Conemans J. Allergic urticarial rash from oral codeine. Contact Dermatitis 1986;14:209-214
• De Groot AC. Contact allergy to EDTA in a topical corticosteroid preparation. Contact Dermatitis 1986;15:250-252
• De Groot AC, Weijland JW. Contact allergy to chloroacetamide in an "anti-wrinkle" serum. Contact Dermatitis 1986;15:97-98
• 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

Chloral hydrate

• De Groot AC, Conemans J. Chloral hydrate: the contact allergen that fell asleep. Contact Dermatitis 1987;16:229-231

Chloral hydrate was a sleeping aid that for some reason was incorporated into a topical remedy. Because contact allergy hadn't been published for the previous 50 years, I ended the article with the sentence 'Our case report may be just a ''yawn'' of a contact allergen that has fallen asleep'.

• De Groot AC, Nater JP, Herxheimer A. Minoxidil: hope for the bald? The Lancet 1987;i:1019-1022
• 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
• De Groot AC, Weijland JW. Contact allergy to butyl methoxydibenzoylmethane. Contact Dermatitis 1987;16:278
• 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, Weijland JW. Hidden contact allergy to formaldehyde in imidazolidinyl urea. Contact Dermatitis 1987;17:124-125
• De Groot AC, Conemans J. Contact allergy to metipranolol. Contact Dermatitis 1988;18:107-108
• 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, van Joost Th, Bos JD, van der Meeren HLM, Weijland JW. Patch test reactivity to DMDM hydantoin. Relationship to formaldehyde allergy. Contact Dermatitis 1988;18:197-201
• De Groot AC, Bruijnzeel DP, Jagtman BA, Weijland JW. Contact allergy to diazolidinyl urea (Germall II). Contact Dermatitis 1988;18:202-205
• De Wit FS, de Groot AC, Weijland JW, Bos JD. An outbreak of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener. Contact Dermatitis 1988;18:280-283
• De Groot AC, Bruijnzeel DP, van Joost Th, Weijland JW. Cosmetic allergy from myristyl alcohol. Contact Dermatitis 1988;19:76-77
• 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, Gerkens F. Contact urticaria from a chemical textile finish. Contact Dermatitis 1989;20:63-64

This is one of my favorite publications, described by Contact Dermatitis' editor-in-chief, Richard Rycroft, as 'superb', because of its humour. It's about a man who developed an allergy to a component of his trousers, which gave him hives and made him subsequently go into shock. I described it like this:

'Sometimes, attacks on human health come from unexpected directions. This is the story of a man whose very own trousers caused him to collapse.

Case Report

A 55-year-old man in good health noticed a burning feeling on his legs while driving his car to work. He then developed shortness of breath and became dizzy. The patient just managed to get to work, but collapsed as soon as he had arrived. He was brought to a hospital, where a 'rash' was noted on his upper legs, which 'soon' disappeared. The patient quickly recovered in hospital. No cause for the collapse was found, but hyperventilation was suggested as a possible etiology. Ten minutes after the patient had dressed to go home, he once again noticed burning on his legs and shortness of breath. He took off his trousers, told the doctor that his diagnosis had been wrong, and asked his wife to bring him an old pair of trousers that he knew he could trust'.

• De Kort WJA, de Groot AC. Clindamycin allergy presenting as rosacea. Contact Dermatitis 1989;21:72-73
• De Groot AC, Weijland JW. Cosmetic allergy to the UV-absorber bornelone. Dermatosen 1989;37:13-15
• De Groot AC. Oleamidopropyl dimethylamine. Dermatosen 1989;37:101-105
• De Groot AC, Young E. The role of contact allergy to aeroallergens in atopic dermatitis. Contact Dermatitis 1989;21:209-214
• De Groot AC, Conemans JMH. Nystatin allergy: Petrolatum is not the optimal vehicle for patch testing. Dermatol Clin 1990;8:153-155
• De Groot AC, Conemans JMH. Contact allergy to furazolidone. Contact Dermatitis 1990;22:202-205
• De Groot AC. The frequency of contact allergy in atopic patients with dermatitis. Contact Dermatitis 1990;22:273-277
• De Groot AC. Labelling cosmetics with their ingredients. Brit med J 1990;300:1636-1638
• De Groot AC, Weijland JW. Cosmetic allergy from the aminoketone colour Basic blue 99 (CI 66059). Contact Dermatitis 1990;23:56-57
• De Groot AC, Gerkens F. Occupational airborne contact dermatitis from octyl gallate. Contact Dermatitis 1990;23:184-186
• De Groot AC, van Wijnen WG, Van Wijnen-Vos M. Occupational contact dermatitis of the eyelids, without ocular involvement, from thimerosal in contact lens fluid. Contact Dermatitis 1990;23:195
• De Groot AC, Baar AJM, Terpstra H, Weijland JW. Contact allergy to moist toilet paper. Contact Dermatitis 1991;24:135-136
• De Groot AC, Conemans JMH. Systemic allergic contact dermatitis from intravesical instillation of the antitumor antibiotic mitomycin C. Contact Dermatitis 1991;24:201-209

Euxyl ® K 400 (Methyldibromo glutarinitrile and phenoxyethanol)

• De Groot AC, Weijland JW. Contact allergy to methyldibromoglutaronitrile in the cosmetics preservative Euxyl K 400. Am J Contact Dermatitis 1991;2:31-32

Euxyl ® K 400 is a preservative consisting of methyldibromo glutaronitrile and phenoxyethanol. Due to the many allergic reactions to Kathon CG and the extensive coverage of it in the scientific literature and the popular press, the cosmetic industry had to look for another effective preservative and Euxyl K 400 was thought to be a suitable candidate. It was certainly effective, but unfortunately it also caused a great number of allergic reactions caused by the component methyldibromo glutaronitrile. I have also written several articles about this, which are listed below. The substance caused so many cases of allergic contact eczema that we already asked the question in 1992 in the Dutch Journal of Medicine (Nederlands Tijdschrift voor Geneeskunde) whether replacing Kathon CG with Euxyl K 400 had not actually changed the situation from bad to worse. Three years later, when we had gained some more experience in the Netherlands and many publications about allergy problems with Euxyl K 400 had also appeared from other countries, we answered the question, again in the Dutch Journal of Medicine, with 'yes, is has gotten worse'.

The European Society of Contact Dermatitis urged the European Commission to regulate the use of the preservative. From 2008 on, Euxyl K 400 was no longer allowed to be used in stay-on cosmetics, i.e. cosmetics that remain on the skin after application, such as creams. Its use was also banned from 2010 in rinse-off (wash-off) products. The latter was probably an exaggeration. These products, such as shampoo, liquid soap and bubble bath, are immediately strongly diluted with water during use and are also washed off the skin after a short time. The contact time with the skin is therefore short, the concentration particularly low. The risk of allergic reactions is therefore very small, certainly no greater than many other ingredients that are allowed in stay-on products.

• De Groot AC, Bruijnzeel DP, Coenraads PJ, Crijns MB, van Ginkel CJW, van Joost Th, van der Kley AJM, Meinardi MMHM, Smeenk G, Weijland JW. Frequency of allergic reactions to methyldibromoglutaronitrile (1,2-dibromo-2,4-dicyanobutane) in the Netherlands. Contact Dermatitis 1991;26:260-261
• Hulsmans R-FHJ, van der Kleij AMJ, Weijland JW, de Groot AC. Vervangen van Kathon CG door Euxyl K 400: van de regen in de drup? Ned Tijdschr Geneeskd 1992;136:587-588
• Hulsmans R-FHJ, Lucker GPH, van der Kleij AMJ, de Groot AC. Kathon CG und Methyldibromglutaronitril: wichtige Kontaktallergene bei Patienten mit Perianalekzem. Vasomed 1994;4:706-709
• De Groot AC. Methyldibroomglutaronitril: een belangrijk allergeen in kosmetica en vochtige toiletdoekjes. Ned Tijdschr Derm Venereol 1995;5:258-259
• De Groot AC. Methyldibroomglutaronitril: inderdaad van de regen in de drup. Ned Tijdschr Geneeskd 1995;139:1850
• De Groot AC, van Ginkel CJW, Weijland JW. Methyldibromoglutaronitrile (Euxyl K 400): An important "new" allergen in cosmetics. J Am Acad Dermatol 1996;35:743-747
• De Groot AC, de Cock PAJJM, Coenraads PJ, CJW van Ginkel, BA Jagtman, T van Joost, AMJ van der Kleij, MMHM Meinardi, G Smeenk, PGM van der Valk, HB van der Walle, JW Weijland. Methyldibromoglutaronitrile is an important contact allergen in the Netherlands. Contact Dermatitis 1996;34:118-20
• De Groot AC, van Ginkel CJW, Weijland JW. How to detect sensitization to Euxyl K 400. Contact Dermatitis 1996;34:373-374

Up to here articles on Euxyl K 400

• De Groot AC. Choosing preservatives: Dermato-allergenic considerations. Cosmetics & Toiletries 1991;106:37-38
• De Groot AC, van der Meyden APM. Purpuric allergic drug eruption from intravesical instillation of the antitumor antibiotic Mitomycin C. Dermatosen 1991;39:84-86
• De Groot AC, Conemans JMH, Schutte Th. Contact allergy to di-isopropyl sebacate in Zineryt @ lotion. Contact Dermatitis 1991;25:260-261
• De Groot AC, White IR. Cosmetic ingredient labelling in the European Community (Editorial). Contact Dermatitis 1991;25:273-276
• De Groot AC, Berretty PJM, van Ginkel CJW, den Hengst CW, van Ulsen J, Weijland JW. Allergic contact dermatitis from tocopheryl acetate in cosmetic creams. Contact Dermatitis 1991;25:302-304
• De Groot AC, van der Meijden APM, Conemans JMH, Maibach HI. Frequency and nature of cutaneous reactions to intravesical instillation of mitomycin for superficial bladder cancer. Urology 1992;40(suppl1):16-19
• De Groot AC, Weijland JW. Systemic contact dermatitis from tea tree oil. Contact Dermatitis 1992;27:279-280
• De Groot AC (anoniem). Rash promises for topical antihistamines. Drugs and Therapeutics Bulletin 1992;30:49-50
• De Groot AC, van der Kleij AMJ, Bruijnzeel DP, Meinardi MMHM, Smeenk G, van Joost Th, Pavel S. Frequency of false-negative reactions to the fragrance mix. Contact Dermatitis 1993;28:139-140
• De Groot AC, Weijland JW. Contact allergy to tea tree oil. Contact Dermatitis 1993;28:309-310

Lipoatrophia semicircularis

• De Groot AC. Is lipoatrophia semicircularis induced by pressure? Brit J Dermatol 1994;131:887-890

This is one of the few articles that is not about contact allergy. Lipoatrophia semicircularis is a characteristic condition seen mainly in young women. It is characterized by semicircular depressions in the front and sides of the thighs due to loss of subcutaneous fat (lipoatrophia). In the popular press it is sometimes referred to as 'dented thighs' or 'ribbed thighs' (literal translation from Dutch).

Lipoatrophia semicircularis (photo derived from Nederlands Tijdschrift voor Geneeskunde 2005;149:952)

I described 10 women with this harmless condition. The first patient who came to me with this told me that several others in the company where she worked had similar abnormalities. By sending a letter to all employees via the human resources department, I tracked down 9 others with lipoatrophia semicircularis.

• De Groot AC. Contact allergy to calcipotriol. Contact Dermatitis 1994;30:242-243
• De Groot AC. Occupational contact allergy to alpha-naphthyl glycidyl ether. Contact Dermatitis 1994;30:253-255
• De Groot AC, van der Walle HB, Weijland JW. Contact allergy to cocamidopropyl betaine. Contact Dermatitis 1995;33:419-22
• De Groot AC, Weijland JW. Contact allergy to disodium cocoamphodipropionate. Contact Dermatitis 1996;35:248-249
• De Groot AC. Contact allergy to polyvinylpyrrolidone/hexadecene copolymer previously reported. Am J Contact Dermatitis 1996;7:260
• De Groot AC. Airborne allergic contact dermatitis from tea tree oil. Contact Dermatitis 1996;35:304-5 

• De Groot AC, Frosch PJ. Adverse reactions to fragrances . A clinical review. Contact Dermatitis 1997;36:57-86

Until recently, this review article on side effects of fragrance ingredients was the largest article ever published in Contact Dermatitis with 29 pages. Currently, the largest is another publication written by me: De Groot AC. Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review. Contact Dermatitis 2022;86(6):443-479, which has 37 pages. Up to 2020, the fragrance article has had 197 citations, i.e. it has been referred to in 197 scientific publications. It established my name in the field of allergy to perfumes and I have subsequently received several invitations to write articles on the subject, especially chapters in books. I received a very nice response from Prof. Albert Kligman from the United States; his letter (at that time we still wrote letters, e-mails were not really established yet) is pictured below.

Kligman was famous for his multifaceted research, including on acne and eczema. His most famous research concerned the effect of vitamin A acid (retinoic acid) on acne and skin aging. He showed that the skin does indeed become 'younger' and that the product can improve (superficial) wrinkles. To date, this is the only substance that has a proven 'anti-wrinkle' effect. Prof. Kligman, then in his late 70s, was highly critical of several aspects of routine patch testing, including its interpretation. He ended his publication 'Kligman AM. A personal critique of diagnostic patch testing. Clin Dermatol 1996;14:35-40' with the following words:

'I have a suggestion for the leadership of the contact dermatitis societies. Instead of holding so many luxurious meetings in charming places where there is excellent food and drink, a fund could be set up from the mostly well-off members to support rigorous investigations of the many serious and unsolved problems. A proper mix of investigators would include dermatologists, epidemiologists, statisticians, immunologists, and allergists. This is clearly what should be done now. Unfortunately, at age 79, I shall not live to see it come about'. Kligman could not have known at that time that he would die only 14 years later.

In our review article, Peter Frosch and I had criticized the very many 'positive' patch test reactions of the fragrance mix in particular, which in our opinion were often the result of irritation and were therefore 'false positive'. The distinction between irritation and allergy was also an important topic in Kligman's critical article, which probably prompted his kind and complimentary letter. Incidentally, he made a mistake, because he wrote 'Adverse reactions to cosmetics' (the title of my dissertation) instead of 'Adverse reactions to fragrances'. I hope that I will also be able to make such small mistakes at that age.

• De Groot AC. Vesicular dermatitis of the hands secondary to perianal allergic contact dermatitis caused by preservatives in moistened toilet tissues. Contact Dermatitis 1997;36:173-174
• De Groot AC. Cocamidopropyl betaine: A "new" important cosmetic allergen. Dermatosen 1997;45:60-63
• De Groot AC. Contact allergens - What's new? Cosmetic dermatitis. Clinics in Dermatology 1997;15:485-492
• De Groot AC, Weijland JW. Conversion of common names of cosmetic allergens to the INCI nomenclature. Contact Dermatitis 1997;37:145-150
• De Groot AC. Fatal attractiveness: the shady side of cosmetics. Clinics in Dermatology 1998;16:167-179
• De Groot AC. Clinical relevance of positive patch test reactions to preservatives and fragrances. Contact Dermatitis 1999;41:224-227
• De Groot AC, Coenraads PJ, Bruynzeel DP, Jagtman BA, van Ginkel CJW, Noz K, van der Valk PGM, Pavel S, Vink J, Weijland JW. Routine patch testing with fragrance chemicals in The Netherlands. Contact Dermatitis 2000;42:184-185
• De Groot AC, Klein Poelhuis JW. Ectropion caused by periocular dermatitis. J Am Acad Dermatol 2001;44:385-386
• Roggeband R, Basketter DA, de Groot AC, Robinson MK, Gerberick GF. Labelling of skin sensitizers: the new European Dangerous Preparations Directive. Contact Dermatitis 2001;44:321-324
• De Groot AC. Dermatological problems linked to perfumes. J Toxicol – Cutaneous and Ocular Toxicology 2002;21:265-271
• De Groot AC, Flyvholm M-A, Lensen GJ, Menné T, Coenraads PJ. Formaldehyde releasers: relationship to formaldehyde contact allergy. I. Contact allergy to formaldehyde and inventory of formaldehyde-releasers. Contact Dermatitis 2009;61:63-85
• Jonkman MF, de Groot AC, Slegers TPAM, de Jong MCJM, Pas HH. Immune diagnosis of pure ocular mucous membrane pemhigoid: indirect immunofluorescence versus immunoblot. Eur J Dermatol 2009;19:456-460
• De Groot AC, White IR, Flyvholm M-A, Lensen G, Coenraads P-J. Formaldehyde-releasers: relationship to formaldehyde contact allergy. II. Formaldehyde-releasers used in cosmetics. Part 1. Characterization, frequency and relevance of sensitization, and frequency of use in cosmetics. Contact Dermatitis 2010;62:2-17
• De Groot A, White IR, Flyvholm M-A, Lensen G, Coenraads P-J. Formaldehyde-releasers: relationship to formaldehyde contact allergy. II. Formaldehyde-releasers used in cosmetics. Part 2. Patch test relationship to formaldehyde contact allergy, experimental provocation tests, amount of formaldehyde released and assessment of risk to consumers allergic to formaldehyde. Contact Dermatitis 2010;62:18-31
• De Groot AC, Maibach HI. Does allergic contact dermatitis from formaldehyde in clothes treated with durable-press chemical finishes exist in the USA? Contact Dermatitis 2010;62:127-136
• De Groot AC, Veenstra M. Formaldehyde-releasers in cosmetics in the USA and in Europe. Contact Dermatitis 2010;62:221-224
• De Groot AC, Coenraads P-J. Twenty-five years quaternium-15 in the baseline series: does it deserve its place there? Contact Dermatitis 2010:62:210-220
• De Groot AC, Le Coz CJ, Lensen G, Flyvholm M-A, Maibach HI, Coenraads P-J. Formaldehyde releasers: relationship to formaldehyde contact allergy. Formaldehyde-releasers in clothes: durable press chemical finishes. Part 1. Contact Dermatitis 2010;62:259-271
• De Groot AC, Maibach HI. Frequency of sensitization to common allergens: comparison between Europe and the USA. Contact Dermatitis 2010;62:325-329
• De Groot AC, Le Coz CJ, Lensen GJ, Flyvholm M-A, Maibach HI, Coenraads P-J. Formaldehyde-releasers: relationship to formaldehyde contact allergy. Part 2. Formaldehyde-releasers in clothes: durable press chemical finishes. Contact Dermatitis 2010;63:1-9
• Emeis D, de Groot AC, Brinkmann J. Determination of formaldehyde in formaldehyde-releaser patch test preparations. Contact Dermatitis 2010;63:57-62
• De Groot AC, Geier J, Flyvholm M-A, Lensen G, Coenraads P-J. Formaldehyde-releasers: Relationship to formaldehyde contact allergy. Metalworking fluids and remainder, part 1. Contact Dermatitis 2010;63:117-128
• De Groot AC, Geier J, Flyvholm M-A, Lensen G, Coenraads P-J. Formaldehyde-releasers: Relationship to formaldehyde contact allergy, part 2. Metalworking fluids and remainder. Contact Dermatitis 2010;63:129-139
• De Groot AC, Blok J, Coenraads P-J. Relationship between formaldehyde and quaternium-15 contact allergy. Influence of strength of patch test reaction. Contact Dermatitis 2010;63:187-191
• De Groot AC. Contact allergy to formaldehyde (Invited commentary). Br J Dermatol 2011;164(3):463
• De Groot AC. Side-effects of henna and semi-permanent ‘black henna’ tattoos: a full review. Contact Dermatitis 2013;69:1-25

• Franken L, de Groot A, Laheij-de Boer A-M. Allergic contact dermatitis caused by menthoxypropanediol in a lip cosmetic. Contact Dermatitis 2013;69:377-378

Allergic contact eczema of the lips and the skin around them due to the use of lip balm

• De Groot AC. Propolis: a review of properties, applications, chemical composition, contact allergy, and other adverse effects. Dermatitis 2013;24:263-282
• De Groot AC, van Zuuren EJ, Hissink D. Contact allergy to Tinosorb® M: recommendations for diagnostic improvement. Contact Dermatitis 2014;70:251-254
• De Groot AC, Roberts DW. Contact and photocontact allergy to octocrylene: a review. Contact Dermatitis 2014;70:193-204
• Dong H, Xu D, Hu Y, de Groot AC. Erythema multiforme-like eruption following acute allergic contact dermatitis after exposure to the emulsified herbicide acetochlor. Contact Dermatitis 2014;71:178-179
• De Groot AC, Rustemeyer Th, Hissink D, Bakker M. Contact allergy to capryloyl salicylic acid. Contact Dermatitis 2014;71:185-187
• De Groot AC. New contact allergens: 2008 to 2015. Dermatitis 2015;26:199-215                                                                    

Essential oils  

After the release of the book De Groot AC, Schmidt E. Essential oils: contact allergy and chemical composition. Boca Raton, Fl., USA: CRC Press, Taylor and Francis Group, 2016, Erich Schmidt and I published 8 articles on essential oils, mainly in Dermatitis and Contact Dermatitis. That was easy, because we already had all the literature plus the data had all been presented in the book. And yes, it was the perfect way to promote the book repeatedly!

• De Groot AC, Schmidt E. Eucalyptus oil and tea tree oil. Contact Dermatitis 2015;73:381-386
• De Groot AC, Schmidt E. Essential Oils, Part I: Introduction. Dermatitis 2016;27:39-42
• De Groot AC, Schmidt E. Essential Oils, Part II: General aspects. Dermatitis 2016;27:43-49
• De Groot AC, Schmidt E. Essential Oils, Part III: Chemical composition. Dermatitis 2016;27:161-169       
• De Groot AC, Schmidt E. Essential oils, Part IV: Contact allergy. Dermatitis 2016;27:170-175
• De Groot AC, Schmidt E. Tea tree oil: contact allergy and chemical composition. Contact Dermatitis 2016;75:129-143
• De Groot AC, Schmidt E. Essential Oils, Part V: Peppermint oil, lavender oil, and lemongrass oil. Dermatitis 2016;27:325-332
• De Groot AC, Schmidt E. Essential oils, Part VI: Sandalwood oil, ylang-ylang oil, and jasmine absolute. Dermatitis 2017;28:14-21

• De Groot AC, Tupker R, Hissink D, Woutersen M. Allergic contact cheilitis caused by olaflur in toothpaste. Contact Dermatitis 2017;76:61-62
• De Groot AC. Contact allergy to (ingredients of) toothpastes. Dermatitis 2017;28:95-114
• De Groot AC, Jagtman BA, Woutersen M. Contact allergy to neem oil. Dermatitis 2017;28:360-362
• De Groot AC. Myroxylon pereirae resin (Balsam of Peru) – A critical review of the literature and assessment of the significance of positive patch test reactions and the usefulness of restrictive diets. Contact Dermatitis 2019;80:335-353. 

• De Groot AC. Linalool hydroperoxides. Dermatitis 2019;30(4):243-246
• De Groot A, Gilissen L, Geier J, Orton D, Goossens A. Adding sorbitan sesquioleate to the European baseline series: Necessary, reasonable, or unavoidable? Contact Dermatitis 2019;81:221-225
• De Groot AC. Limonene hydroperoxides. Dermatitis 2019;30:331-335
• De Groot AC. Fragrances: Contact allergy and other adverse effects. Dermatitis 2020;31;13-35 Dermatitis Review Article of the Year 2020
• Van Amerongen CCA, de Groot A, Volkering RJ, Schuttelaar MLA. Cheilitis caused by contact allergy to toothpaste containing stannous (tin) – two cases. Contact Dermatitis 2020;83:126-129
• De Groot AC. Allergic contact dermatitis from topical drugs: An overview. Dermatitis 2021;32(4):197-213
• De Groot AC. Systemic allergic dermatitis (systemic contact dermatitis) from pharmaceutical drugs: a review. Contact Dermatitis 2022;86:145-164 doi: 10.1111/cod.14016

• De Groot AC. Patch Testing in drug eruptions: Practical aspects and literature review of eruptions and culprit drugs. Dermatitis 2022;33(1):16-30 Dermatitis Review Article of the Year 2022
• De Groot AC. Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review. Contact Dermatitis 2022;86(6):443-479. doi:10.1111/cod.14090 
• De Groot AC. Results of patch testing in Acute generalized exanthematous pustulosis (AGEP): a literature review. Contact Dermatitis 2022;87(2):119-141. doi:10.1111/cod.14075                                                                                  

• De Groot AC, Rustemeyer T. 2-Hydroxyethyl methacrylate (HEMA): A clinical review of contact allergy and allergic contact dermatitis—Part 1. Introduction, epidemiology, case series and case reports. Contact Dermatitis. 2023;89(6):401-433. doi: 10.1111/cod.14405.

• De Groot AC, Rustemeyer T. 2-Hydroxyethyl methacrylate (HEMA): a clinical review of contact allergy and allergic contact dermatitis. Part 2. Cross- and co-sensitization, other skin reactions to HEMA, position of HEMA among (meth)acrylates, sensitivity as screening agent, presence of HEMA in commercial products and practical information on patch test procedures. Contact Dermatitis 2024;90(1):1-16. doi: 10.1111/cod.14430

• Steunebrink IM, de Groot A, Rustemeyer T. Presence of 2-hydroxyethyl methacrylate (HEMA) and other  meth)acrylates in nail cosmetics, and compliance with EU legislation: An online market survey.

  Contact Dermatitis. 2024 Jan;90(1):60-65. doi: 10.1111/cod.14441. 

• Steunebrink IM, de Groot A, Rustemeyer T. Contact allergy to acrylate-containing nail cosmetics: A retrospective 8-year study. Contact Dermatitis. 2024;90:262-265. doi:10.1111/cod.14475.

• Kocabas G, Steunebrink IM, de Groot A, Rustemeyer T. Results of patch testing 2-hydroxyethyl methacrylate (HEMA) in the European baseline series: A 4-year retrospective study. Contact Dermatitis 2024;90:466-469. doi: 10.1111/cod.14488.

• Kocabas G, Ipenburg NA, de Groot A, Rustemeyer T. Results of patch testing propolis in the European baseline series: A 4-year retrospective study. Contact Dermatitis  2024;91(5):375-378. doi: 10.1111/cod.14678.

• Kocabas G, Ipenburg NA, de Groot AC, Rustemeyer T. 2-Hydroxyethyl methacrylate (HEMA) 1% versus 2%.

  Contact Dermatitis. 2024;91(2):171‐172. doi:10.1111/cod.14571

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