Correspondence Clinical Letter
Clinical Letter Occupational koebnerization of psoriasis caused by glyphosate
DOI: 10.1111/ddg.13393
Dear Editors, Glyphosate (N-(phosphonomethyl) glycine), brand name: Roundup®) [1] is a broad-spectrum herbicide that is widely used in agriculture. Controversy as to its approval in the EU has been lingering since it was classified as “probably carcinogenic to humans” by the International Agency for Research on Cancer (IARC) [2]. There is confl icting data on the cutaneous toxicity of glyphosate [1, 3-5]. According to the safety data sheet [6], “Roundup® Solid” is a mixture composed of the isopropylamine salt of glyphosate, a wetting agent, and water. The concentrate is mixed with water and then transferred into a spray container. According to the safety data sheet, no significant adverse effects are to be expected with short-term skin contact, as long as the instructions for use are followed [6]. In case of skin contact, the contaminated clothing as well as the watch and jewelry should be removed, and the affected skin should be rinsed with plenty of water. A case evaluated in the context of an expert medical assessment commissioned by a social welfare court shows that irritant contact dermatitis is to be expected after accidental exposure to glyphosate, which – in the present case – led to koebnerization of psoriasis. A 53-year-old woman, who worked as a park gardener and had no history of previous skin problems, sued for recognition of her skin lesions as the result of an occupational accident. While pouring the Roundup® Solid fluid into a container, some of it had entered the claimant’s forearm-length rubber gloves, thus contaminating her elbows, forearms, and hands. She had immediately doffed the gloves and rinsed her arms with water. The accident report fi led by her employer confi rmed this course of events. A week later, skin lesions had developed on the woman’s arms and forearms. Based on the clinical fi ndings consisting of painful erythematous swelling and scaling of the hands and forearms, the treating dermatologist had diagnosed toxic hand dermatitis and initiated treatment with topical and systemic corticosteroids. Subsequently, the patient had developed erythematous plaques on the hands and forearms, which had then spread across the entire body. Given these typical skin lesions, psoriasis had been diagnosed without histological confi rmation. Extensive patch testing had only revealed a positive reaction to nickel-II sulfate. Standard
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prick testing (including inhalant allergens) had shown no pathological fi ndings; however, the atopy score had been increased (16 points). Despite multimodal therapy as an inpatient, cream-PUVA therapy of the hands, and systemic treatment with acitretin, methotrexate, and cyclosporine A, the lesions had not completely resolved. Clinical examination in the context of the expert medical assessment showed hyperkeratotic plaques with erythema on the dorsal aspects of the metacarpophalangeal joints. Isolated erythemato-squamous plaques were noted on the extensor aspects of the forearms, the elbows, as well as the legs and ears. The three typical psoriasis phenomena were positive. All fi ngernails revealed longitudinal and transverse grooves as well as small pits. Based on history, medical records, and clinical fi ndings, the patient was diagnosed with psoriasis (as Koebner phenomenon) on the hands and forearms caused by acute irritant contact dermatitis following accidental skin contact with Roundup® Solid. Irritant contact dermatitis following accidental contact with Roundup® may not only be caused by the active ingredient glyphosate but also by the wetting agent (polyethoxylated tallow amine [POEA] is most frequently used) as well as by the interaction of both substances. Other undeclared components contained in a mixed Roundup® solution may include antifoaming agents, dyes, biocides, and inorganic ions for pH adjustment. According to the German Institute for Risk Assessment (BfR), the toxicity of certain glyphosate-containing herbicides may be higher than that of the active substance itself [7] due to additives in the solution (such as tallow amines used as wetting agents). A study by Maibach investigating the irritant effects of glyphosate by performing patch tests (with glyphosate 10 % in aqueous solution) on 346 volunteers found no evidence of induction of allergic or irritant contact dermatitis [1]. The herbicide was reported to be less irritant than a conventional dishwashing detergent or an all-purpose cleaner. The substance is therefore classified as having no sensitizing, corrosive, or irritant effects. However, there have also been case reports of acute irritant contact dermatitis following exposure to glyphosate [3, 5]. This apparent contradiction is resolved by reviewing the Maibach study more closely [1]: While glyphosate had virtually no irritant effects on intact skin, it led to pronounced irritant reactions in half of the subjects when applied to abraded skin; these effects were significantly stronger than those produced by the irritants used for comparison. In individuals with preexisting skin damage and under occlusive conditions, contact with glyphosate is likely to result in irritant contact dermatitis, which may be severe in some cases. The delayed onset of skin lesions in this patient may be regarded as a case of acute delayed irritant dermatitis, as described for certain irritants [8].
© 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd. | JDDG | 1610-0379/2018/1601
Correspondence Clinical Letter
The term ‘isomorphic response’ (Koebner phenomenon) refers to the occurrence of isomorphic cutaneous lesions as a consequence of mechanical, chemical, thermal, or infectious triggers in (inducible) dermatoses such as psoriasis [9]. In the present case, the expert medical assessment was supposed to determine whether, in terms of scientific and legal causation, there was more evidence for than against the claim that the psoriasis of the hands and forearms had been triggered by irritant contact dermatitis as the result of an occupational accident [10, 11]. Given the temporal and local correlation, the claim was recognized as regards the psoriatic lesions on the hands and forearms, yet not for the generalized lesions as there is no evidence for the induction of generalized psoriasis by a localized Koebner phenomenon. Conflict of interest None.
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Peter Elsner, Susanne Darr-Foit, Sibylle Schliemann Department of Dermatology, Jena University Hospital
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Correspondence to Prof. Dr. med. Peter Elsner Department of Dermatology Jena University Hospital
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Erfurter Strasse 35 07743 Jena, Germany E-mail:
[email protected]
References 1
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Fritschi L, McLaughlin J, Sergi CM et al. Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. Red 2015; 114 . Available from: http://www.gmofreeusa. org/wp-content/uploads/2015/03/2015_03_TheLancetOncology_CarcinogenicityOfTetrachlorvinphosParathionMalathionDiazinonGlyphosate.pdf [Last accessed May 24, 2017]. Heras-Mendaza F, Casado-Fariñas I, Paredes-Gascón M, Conde-Salazar L. Erythema multiforme-like eruption due to an irritant contact dermatitis from a glyphosate pesticide. Contact Dermatitis 2008; 59 (1): 54 – 6. Bradberry SM, Proudfoot AT, Vale JA . Glyphosate poisoning. Toxicol Rev 2004; 23( 3): 159 – 67. Amerio P, Motta A , Toto P et al. Skin toxicity from glyphosatesurfactant formulation. J Toxicol Clin Toxicol 2004; 42(3): 317– 9. Monsanto Europe SA. Sicherheitsdatenblatt Roundup Solid. 2012. Available from: http://www.wurth-pflanzenschutz.de/tl_files/Sicherheitsdatenblatt/sdb/Pflanzenschutz_5411773999999.html. Risikobewertung BF. Fragen und Antworten zum Verfahren der Neubewertung von Glyphosat im Rahmen der EU-Wirkstoffprüfung 2015. Available from: http://www.bfr.bund.de/ cm/343/fragen-und-antworten-zum-verfahren-der-neubewertung-von-glyphosat-im-rahmen-der-eu-wirkstoffpruefung. pdf [Last accessed January 1, 2017]. Chew A-L, Maibach HI. Occupational issues of irritant contact dermatitis. Int Arch Occup Environ Health 2003; 76( 5): 339 – 46. Weiss G, Shemer A , Trau H. The Koebner phenomenon: review of the literature. J Eur Acad Dermatol Venereol 2002; 16( 3): 241 – 8. Mahler V, Diepgen T, Skudlik C et al. Psoriasis predisposition and occupational triggering factors in the appraisal of occupational medical expertises. J Dtsch Dermatol Ges 2014; 12(6):519 –29. Angelovska I, Mahler V. Occupational palmoplantar psoriasis: a clinical case series with consideration of the S1 guidelines on expert medical assessments of occupational psoriasis. J Dtsch Dermatol Ges 2014; 12(8):697–708.
Maibach HI. Irritation, sensitization, photoirritation and photosensitization assays with a glyphosate herbicide. Contact Dermatitis 1986; 15( 3): 152 – 6.
© 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd. | JDDG | 1610-0379/2018/1601
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