Patch testing fifth edition 

Against all odds: a fifth edition

When the 4th edition of Patch testing came out in 2018, I was almost certain that it would be the last. The first edition appeared in 1986, the second in 1994, the third in 2008 (self-published from here onwards) and the fourth 10 years later. The period between two editions of the book has thus varied from 8 to 14 years. If that time frame becomes much shorter, then there is actually too little new material to justify a new edition. Moreover, I would end up with a large number of unsold books and printing a new edition is expensive. In addition, I took into account that, for reasons explained elsewhere, fewer and fewer books would be sold. Not everyone who has bought edition 4 is willing to buy edition 5 after a few years, if it contains little news. And suffering a loss on adegroot publishing, which already has a high hot air content anyway, was not the intention. Therefore, I reasoned, logically a fifth edition could not be published until 2026-2028. I had serious doubts whether I would still feel like doing this at the age of 75 or 77 and, let's not forget, I would also need the opportunity to do so, both quoad vitam and in terms of adequate data provision: I would need access to a digital university library! And yet that 5th edition has appeared; I'd like to tell you how this persued. 

Free digital updates

With the 3rd edition (2008) I had written in my advertising email messages to the members of the American Contact Dermatitis Society (ACDS), the European Society of Contact Dermatitis (ESCD) and selected members of the Dutch Association for Dermatology and Venereology (NVDV), that everyone who purchases a copy is entitled to free digital updates. Indeed, I wrote such an update to the third edition 3 times (2008-2010, 2008-2012 and 2008-2015) and they could download it for free from my account at www.researchgate.netI soon decided that I'd better make the updates accessible to everyone, hoping that this would entice some to buy the book for themselves. The journal Dermatitis was willing to publish a very brief note from me stating that updates were available. So these were all updates to the 3rd edition of Patch testing from 2008.

Until recently I had no plans for a digital update of the 4th edition (2018), because very few new allergens have been published in recent years. However, that changed when I wrote the book Monographs in Contact Allergy, Volume 4 – Systemic Drugs. It contains many test concentrations of drugs that were not yet available in the 4th edition. By the way, most of these were already published before 2018, so you would think I had been sleeping, because I missed these test concentrations (and therefore had not included them in the 4th edition). Fortunately that was not the case. The vast majority of allergy studies to these drugs have been published in non-dermatology journals, which I (obviously) did not screen for test concentrations. But I had now found them all while writing the book on Systemic drugs.     

This changed the playing field. I counted 225 'new' allergens with test concentrations in my Monographs 4 book and in the recent volumes of Contact Dermatitis and Dermatitis (2018 – March 2022). New in the sense that they were not yet included in the 4th edition of Patch testing. So now it was worth while making a new digital update 2018-2022 and so I did. I applied for an ISBN/EAN number (actually this is double: the N of ISBN and EAN already stands for 'number') and turned it into a formal digital booklet: De Groot AC. Patch testing, 4th Edition: Update 2018 – 2022. Wapserveen, The Netherlands: acdegroot publishing, 2022 (37 pages). ISBN/EAN 978-90-813233-7-6.


The announcement of its release, together with the publication of the Systemic drugs book in March 2022, was sent to all members of the ESCD, ACDS and NVDV. I hoped that this would allow me to sell a few more copies of my Patch testing book, but that plan seems to have failed miserably. I personally informed the members of the ESCD (about 320) and those of the NVDV (about 800) via personalized emails, which of course was quite a job. In earlier books I had also sent a message to all members of the ACDS myself, but there are about 2500 of them! I was not really looking forward to that now. So I approached Ginger from the ACDS office and asked if she could help me a bit with this. I would have been happy with all the email addresses on an Excel sheet or something similar, but she offered to send my mail (in a slightly modified form, but with the essence of my [advertising] message intact) via the ACDS mailing system, and so it happened. Fantastic! My email to Ginger was overflowing with gratitude. Thus, in the emails announcing the release of Monographs in contact allergy, Volume 4 – Systemic drugs, and the Patch testing update, there were links or attached PDF files presenting the entire table of contents of the Monograph as well as two complete sample chapters that I had selected myself.

I received quite a few nice reactions, especially about the new book in the Monographs in contact allergy series, there were many enthusiastic comments. At least eight colleagues have announced that they had already ordered the book or will do so. I have sent everyone who responded a short thank you email.

When ointments are applied to a so-called 'hypostatic eczema' on the lower legs or to leg ulcers (ulcus cruris), there is a greatly increased risk that the patient will become sensitized and develops  allergic contact dermatitis . The allergen is often lanolin alcohol (wool alcohols) or derivatives thereof (base component), preservatives, Balsam of Peru or topical drugs such as neomycin.

Get to the point, De Groot!

Now I can understand if you are getting a bit impatient and think: 'What does that have to do with the 5th edition, please explain that'. That's a good question, and I'll answer it directly and concisely:  EVERYTHING. Because once the UPDATE 2018-2022 had been produced, all I had to do was insert the data into the existing Word files from Patch testing 2018, have a new cover made, adjust the front matter, write a new Foreword, adjust About the author (and in a frivolous mood I added a color photo of the author this time), renumber the Contents, make one PDF of the entire manuscript and everything is set! And oh yes, I also included the anecdote in which I describe how I earned 30,000 guilders (about 13,500 euros) in 1985 on the first edition. The message was that not only good deeds are punished ('no good deed goes unpunished'), but that this can also apply to enthusiasm. Just read along.



In 1984, I purchased a personal computer, one out of the first shipment of 20 IBM AT’s to arrive in The Netherlands. It cost 17,000 Dutch guilders (DFl.), about 7,725 Euro’s or 8,730 USD. It had a hard disk of 5 Mb (sic) and if you had the bad luck that the disk would crash after a year and one day or later (which was far from uncommon those days), it would set you back another 5,000 DFl. I also bought a D-base program and made a file for each entry in Patch testing: name of the chemical, synonyms, patch test concentrations and vehicles with references, Merck Index number, Cosmetic Ingredient Dictionary Monograph (Yes/No) and Comments (e.g., contact urticaria or photosensitivity reported, 20 controls performed, etc.). With these individual files, I could make a print of the entire Table 1, the heart of the book, in alphabetical order. In fact, by many trials and errors (and admittedly, many sighs and curses), I managed to print the entire book. From a current perspective, it looked rather ugly, but in those days, nobody perceived it as such.

In 1985, I had had several contacts with Elsevier by telephone and letters, I had explained all details of the book and there was much interest in publishing it. One sunny day, I went to Amsterdam to make the final arrangements and sign the contract with the Management. In my briefcase, I had some 30 printed pages (which would now be called Camera-ready copy) with me, of which they knew nothing: I had never told them anything about it. I hoped they would like it and I was certainly not disappointed: the Elsevier people were overflowing with enthusiasm! And then, one of the management team made a tactical error: ''This saves us 200 DFl. per page for typing costs'', she exclaimed. My brain rattled for one second and I quickly responded: ''Excellent, then you can give me half of your savings''. The management was very sporty about it, acknowledged that my request was reasonable and agreed without hesitation. The book had 295 pages, so you do the math! I had earned my computer back and received a handsome royalty on top of this. And an anecdote which still can make me smile, even now, 38 years and 4 more editions of Patch Testing later…….  

For select audience

Incidentally, I decided before I started working on it that I would not publish this 5th edition for commercial purposes as  printed book: producing a completely new edition for 4 years after the previous edition for sale is commercial suicide. But I did plan to have about 30 books produced for myself, family, friends and a number of colleagues.

Was that all I would do with that 5th edition? No, because in the meantime I had approached the ESCD and ACDS and asked their boards if they were interested in the digital files of my book Patch testing to put them on their website and make the book available online for the members of these associations. The fourth edition has already been on the ACDS website since December 2021 and it was replaced by this 5th edition ( The ESCD ( mean-while had also decided to include the book on the website and they were grateful for this new the 5th edition.

In the end, it still took me another week or two to write the 5th edition. Especially delivering the copy exactly the right size and in the right shape to the - new - printing company has been quite problematic. This is because the original Dbase files from 1985 were later converted to Word, but it never became completely perfect. I had to cut the book into 8 different parts and edit each one separately, making sure everything is exactly in the right place with the right margins and the right page numbers. This was not done automatically like in a modern Word file, it all had to be done manually.

Some of the parts of text I wanted out refused to disappear without completely changing the formatting of the rest (that's often a problem with tables). I had to obtain a license to a PDF editing program (no problem, 10 euros for a month; , excellent website, recommended) to be able to perform all kinds of editing. Anyway, with a lot of puzzling I managed to get everything perfect and deliver it to the printer as one complete PDF file of the entire book.

The book needs to be printed

Now to the printer. The book could not be printed by the company that had produced the 4th edition (Bariet Ten Brink in Meppel) because they demanded a minimum edition of 300. That's because this printer uses offset printing, which is very expensive. Therefore, a more modern company, which had previously produced my 2020 autobiography came back into the picture. This company is much more flexible with digital printing and also does printing on demand, and you can order for example 20 copies.  

Previously I was very satisfied with my biography produced by them, which was of perfect quality: snow-white glossy paper, ink-black and razor-sharp lettering, and beautifully sewn bound. Even the photos I scanned turned out beautiful. Every reason to work with this company again, except ……….that they are all smooth modern hip boys and girls who work there. 'What's wrong with that?' I can hear you think. Well, that those modern boys and girls are so busy and - partly because of that - so terribly sloppy!!!!!!! It all has to be done way too fast these days and then mistakes are being made and things are forgotten. From that first time with my biography I can pull out 5 emails from me to my contact at the company in which I politely (it wasn't always easy to be polite I can assure you, I have little tolerance for easily avoidable mistakes) that he had done something wrong again. Hence my hesitation to work with this company again.

Despite this, I decided to hire them and ordered 30 copies of the book. However, my hesitation turned out to be understandable and justified: now I can show 6 of those e-mails in which I point out errors and I have even called them twice! That's very special for me, I prefer email over telephone calls, because in an email I can formulate better and I don't have to be afraid of getting angry on the phone. In one of those conversations I said, 'I'm starting to get a little desperate'. Ah well, I hoped and assumed that the book would turn out very nice again, which it did. And yes, they were nice enough, those boys and girls and never made a fuss, which helps.

The end result

The cover is slightly different from that of the previous editions. The words 'Patch testing, 5th edition. Test concentrations and vehicles for 5200 chemicals' on the cover are now printed in gold and the paper is also of a heavier quality than edition 4 (which was not my intention, but I missed it in the quotation). All in all this 5th edition has become a handsome and rather voluminous book. But the smooth young people had made an error again (Murphy visited them repeatedly): the first batch of 30 books contained my photo in grayscale! Well, of course I rejected them, so they had to produce new ones (and of course had to use their gold stock again, bummer). Also here: all is well that ends well!

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