It is not always chlorhexidine: Identification of benzoxonium chloride and lauramine oxide as culprit allergens in a popular antiseptic in Switzerland.

BACKGROUND: A popular antiseptic spray in Switzerland (Merfen spray), containing chlorhexidine digluconate, benzoxonium chloride and lauramine oxide, is frequently used to treat skin wounds. However, it is also increasingly reported as a major cause of adverse skin reactions, including allergic contact dermatitis (ACD). OBJECTIVES: To investigate the contact allergens responsible for ACD from this antiseptic. PATIENTS/METHODS: Patch tests were performed on seven patients with a clinical history compatible with contact dermatitis from this antiseptic mixture. RESULTS: All patients presented with acute eczematous reactions following contact with either Merfen spray alone, or with multiple products including this spray. Patients showed positive reactions to this product in both patch tests and repeated open application tests (ROATs). Four patients showed dose-dependent reactions to both benzoxonium chloride and lauramine oxide. One patient showed a dose-dependent reaction to the former and a non-dose-dependent reaction to the latter. Finally, two subjects showed responses only to lauramine oxide. One patient reacted to chlorhexidine digluconate 0.5% aq. in addition to both other allergens. CONCLUSIONS: Two commercially unavailable allergens, that is, benzoxonium chloride and/or lauramine oxide were identified as major causes of ACD from Merfen antiseptic spray, whereas chlorhexidine digluconate was a contributing culprit in only one patient.

Contact allergy to and allergic contact dermatitis from formaldehyde and formaldehyde releasers: A clinical review and update.

This review aims to provide a clinically useful update regarding the role of formaldehyde (FA) and its five main releasers (FRs) quaternium-15, diazolidinyl urea, DMDM hydantoin, imidazolidinyl urea, and 2-bromo-2-nitropropane-1,3-diol (bronopol) in contact allergy and allergic contact dermatitis. These ubiquitous preservatives are still often present, and sometimes undeclared, in cosmetics, pharmaceuticals, medical devices, household detergents, and chemical (industrial) products. In Europe, the use of free FA and quaternium-15 in cosmetics is forbidden and contact allergy rates have been found to be stable to decreasing. However, FA/FRs still readily provoke localized (eg, facial/hand), airborne, and generalized dermatitis, and may also complicate atopic and stasis dermatitis, or result in nummular dermatitis. Seborrheic-, rosacea- and impetigo-like dermatitis have recently been reported. For a correct diagnosis, FA 2% aq. (0.60 mg/cm2 ) should be used, and particularly the FRs bronopol 0.5% pet. and diazolidinyl urea 2% pet. should be patch tested separately in a baseline series. If sensitization to FA occurs, both FA and FRs should preferably be avoided, except perhaps for bronopol in case it tests negatively. If a patient reacts to one or more FRs (such as bronopol or diazolidinyl/imidazolidinyl urea), but not to FA, then the specific FR(s) should be avoided.

Contact allergy in a paediatric population observed in a tertiary referral centre in Belgium.

BACKGROUND: Contact allergy is increasingly recognized as being important in children with eczema. OBJECTIVES: To retrospectively analyse the patch test results in children over the past 10 years, aiming to (1) evaluate demographic characteristics and lesion locations, (2) describe frequencies of positive patch test reactions, and (3) investigate the relationship with atopic dermatitis (AD). METHODS: A total of 329 children were patch tested between January 2010 and December 2019 with the European (children) baseline series and/or other series, and the personal product(s) used. RESULTS: A total of 119 (36%) children presented with at least one positive reaction. Children with AD had a higher prevalence of positive reactions compared with the non-AD group (P = .002), but without statistically significant difference regarding sensitization to more than one hapten (P = .39). The face (20.2%), hands (19.3%), feet (16.8%), arms (12.6%), and body folds (10.9%) were the most common sites of primary localizations. The most frequent contact allergens were nickel sulfate and linalool hydroperoxide (both 16%), limonene hydroperoxide (13.5%), and para-phenylenediamine (10.9%). No statistically significant difference for nickel sulfate was found between the AD and non-AD group (P = .20). CONCLUSIONS: Contact allergy in children with eczema was frequently observed in our tertiary referral centre in Belgium as well, confirming the need for patch testing.

Allergic contact dermatitis from ("hypoallergenic") adhesives containing D-limonene.

BACKGROUND: Besides being a potential component of (some species of) colophonium, D-limonene is also used as a tackifier in the production of adhesives. Hydroperoxides of limonene are well-known skin sensitizers. OBJECTIVES: To show that D-limonene may be present in colophonium-containing but also colophonium-free ("hypoallergenic") adhesives, and that patients suffering from allergic contact dermatitis (ACD) from both types of adhesives might display positive patch test reactions to limonene hydroperoxides in this regard. METHODS: Five patients with suspected ACD from adhesives were patch tested to the baseline series (containing limonene hydroperoxides 0.3 and 0.2% pet.), additional series and, if available, to the culprit adhesives. The adhesives labelled as containing colophonium (n = 3) or free from it (n = 2) were analysed with gas chromatography - mass spectrometry (GC-MS) for the presence of D-limonene. RESULTS: All five patients sensitised to adhesives had (strong) positive patch test reactions to limonene hydroperoxides. The presence of D-limonene, and/or related components, could be demonstrated in all three colophonium-containing and, surprisingly, also in two colophonium-free ("hypoallergenic") tapes. CONCLUSIONS: D-limonene may be present in both regular and "hypoallergenic" adhesives, with limonene hydroperoxides potentially contributing to ACD from such medical devices. The use of fragrance chemicals in adhesives deserves further research.

Iatrogenic allergic contact dermatitis in the (peri)anal and genital area.

BACKGROUND: Allergic contact dermatitis (ACD) from topical medication often occurs in occluded areas, for example, with wound treatment, but also in certain body locations, such as the anogenital area. OBJECTIVES: To investigate the demographics and specific lesion location of patients with ACD from topical drugs applied onto the (peri)anal/genital area, and to identify the respective causal topical pharmaceutical products and ingredients involved. METHODS: From January 2000 to December 10, 2018, 532 patients were tested with the baseline series, sometimes with additional series, and the topical medication used along with the ingredients. The relevant data were extracted from our electronic databases developed in-house. RESULTS: Forty-four patients (9%) out of 473 patients suffering from lesions in the (peri)anal/genital area had positive patch test results to topical drug preparations and/or their ingredients, sometimes in association with cosmetics for intimate hygiene. The most frequent sensitizing active principles were local anaesthetics and corticosteroids, while wool alcohols and to a minor extent benzoic acid were the most frequent culprits among the vehicle components and preservative agents, respectively. CONCLUSIONS: The local conditions (eg, occlusion, sweating, moist) in the anogenital area may favour skin sensitization to topical medication used to treat various skin diseases.

Allergic contact dermatitis from potassium sorbate and sorbic acid in topical pharmaceuticals and medical devices.

BACKGROUND: The preservatives sorbic acid (SA) and potassium sorbate (PS) are considered rare skin sensitizers. PS-containing products always contain SA to a certain extent, and positivity to PS may reflect sensitization to SA. Their optimal patch-test conditions are unknown. OBJECTIVES: To report on the outcome of testing with SA and PS in various concentrations and/or vehicles. PATIENTS AND METHODS: Seventeen patients with allergic contact dermatitis from PS/SA-containing topical pharmaceuticals and medical devices were patch tested to SA 2% and 5% pet.; SA 1%, 2%, 3%, 5%. eth.; and/or SA 2% aq., whereas PS was patch tested 5% pet. and/or 5% aq. RESULTS: Only one patient, not tested to the ethanol preparations, presented with a (doubtful) positive reaction to SA 2% pet., while this remained negative in 13 patients who reacted to SA 2% eth. The preparations containing SA 5% pet.; 1%, 3%, and 5% eth.; and SA 2% aq. had little or no additional value. PS 5% pet. performed better than 5% aq., and always mirrored SA sensitization. CONCLUSIONS: Sensitization to SA and PS is probably underestimated. SA 2% eth. and PS 5% pet. are preferred for patch testing, and patients sensitized to SA should avoid PS-containing products. HIGHLIGHTS: Potassium sorbate (PS) and sorbic acid (SA) are widely used preservatives. PS-containing products always contain some SA. Both are considered rare skin sensitizers, but contact allergy in response to them might be underestimated. SA 2% eth. and PS 5% pet., rather than SA 2% pet. and PS 5% aq., respectively, may be required to diagnose contact allergy from PS/SA-containing topical pharmaceuticals and medical devices. A positive patch test to PS reflects sensitization to SA, and patients sensitized to SA should also avoid PS-containing products.

Evolution of methylisothiazolinone sensitization: A Belgian multicentric study from 2014 to 2019.

BACKGROUND: In the 2010s an epidemic of allergic contact dermatitis to methylisothiazolinone (MI) occurred in Europe. European authorities banned the use of methylisothiazolinone in leave-on cosmetics in 2017 and limited its use in rinse-off products in 2018. OBJECTIVES: To investigate the sensitization rate to MI in Belgium between January 2014 and December 2019, and to assess cosensitizations to octylisothiazolinone (OIT) and benzisothiazolinone (BIT) in MI-sensitized patients. METHODS: A retrospective study of patch test results with MI, OIT, and BIT observed in patients attending five Belgian hospitals. RESULTS: Overall, 560 of 10 029 patients (5.58%) had a positive patch test reaction to MI, and its sensitization rate decreased from 7.9% in 2014 to 3.1% in 2019. Rinse-off cosmetics, paints, and detergents were the most prevalent sensitization sources in recent years. Simultaneous reactions readily occurred to OIT, and, surprisingly, and increasingly, also to BIT. CONCLUSIONS: Contact allergy to MI in Belgium has reached a pre-epidemic level, reflecting the impact of recent regulatory measures. Leave-on cosmetics, in contrast to rinse-off products, have almost disappeared as sensitization sources in Europe. Paints and detergents also remain problematic. The remarkably high number of patients (co)sensitized to BIT should be a focus of future research.

Concomitant positive patch test reactions in FreeStyle-allergic patients sensitized to isobornyl acrylate.

BACKGROUND: Concomitant positive patch test reactions in patients sensitized to isobornyl acrylate (IBOA) have rarely been documented. OBJECTIVES: To report concomitant sensitizations in patients with allergic contact dermatitis (ACD) from the glucose sensor FreeStyle Libre and sensitized to IBOA. METHODS: In 2019, 26 patients with suspected ACD from FreeStyle Libre were patch tested to a baseline series and to a (meth) acrylate series containing IBOA and 2-phenoxyethyl acrylate (PEA) 0.1% pet. Diabetes devices and patch test preparations were analyzed with gas chromatography - mass spectrometry (GC-MS) for the presence of IBOA and PEA. RESULTS: Of the 26 patients, 18 (69%) were sensitized to IBOA, and eight (44%) and 11 (61%) of these were co-sensitized to sesquiterpene lactones and fragrances, respectively. Ten patients (56%) were co-sensitized to PEA, which, contrary to IBOA, could not be detected in any device. The PEA test material was shown to be contaminated with IBOA. CONCLUSIONS: Contact allergy to IBOA appears to be declining and IBOA-sensitized patients are most often co-sensitized to sesquiterpene lactones and fragrances. Vigilance is required when patch testing (acrylate) materials obtained from industry, as these might be contaminated and, hence, alter the results and their interpretation.

The presence of benzophenone in sunscreens and cosmetics containing the organic UV filter octocrylene: A laboratory study.

BACKGROUND: The reason why patients photosensitized to the drug ketoprofen (KP) may develop severe photoallergic skin reactions to octocrylene (OCT), an organic ultraviolet filter in sunscreens and cosmetics, remains largely unknown. OCT can be synthesized by using unsubstituted benzophenone (BP), a possible human carcinogen. OBJECTIVES: To verify if, and to what extent, BP residues are present in OCT-containing consumer products. METHODS: The raw material of OCT and 39 skincare products, of which 28 contain OCT, were chemically analysed for the presence of BP by means of liquid chromatography. RESULTS: In the OCT raw material and in all 28 OCT-containing products the presence of BP could be demonstrated, mostly in concentrations above 10 ppm (0.001%), whereas a majority of OCT-free products (8/11, 73%) did not contain BP. Moreover, BP concentrations significantly increased, in a time- and temperature-dependent manner, likely due to the additional degradation of OCT. CONCLUSIONS: Photoallergic contact dermatitis from OCT in patients photosensitized to KP might rely on residual BP impurities. Toxicological and ecological studies that evaluate the safety of OCT might also need to consider the concomitant presence of BP.

Occupational allergic contact dermatitis from systemic drugs.

BACKGROUND: Health-care workers (HCWs) and professionals working in the pharmaceutical industry are at risk of developing occupational allergic contact dermatitis (OACD) from systemic drugs (or drug intermediates). OBJECTIVES: To study demographic characteristics and identify systemic drugs responsible for OACD in patients investigated for contact allergy during the period 2001-2019. METHODS: In the study period, 9780 patients were patch tested with the European baseline series, sometimes with additional series, and other relevant potential allergens. All patients with a positive patch-test reaction to systemic medication exposed to at work were included for further analysis. RESULTS: Of 1248 HCWs examined in our clinic, 201 suffered from OACD. In 26 (13%) dermatitis was caused by skin contact with a systemic drug: 19 nurses, five chemists working in the pharmaceutical industry, one physician, and one veterinarian. In total, 45 positive patch-test reactions to 20 different systemic drugs were found, with tetrazepam (n = 11), ranitidine hydrochloride (n = 5), and zolpidem (n = 4) being the most frequent. Three pharmaceutical chemists were sensitized to a drug intermediate. The lesions were mostly localized on the hands, but often also on the face, as airborne dermatitis. CONCLUSION: As much as 13% of OACD in HCWs, diagnosed in our tertiary referral center, was attributable to systemic drugs, most frequently in nurses.

A survey of members of the European Surveillance System on Contact Allergy and the EU project "StanDerm" to identify allergens tested in cosmetic series across Europe.

BACKGROUND: There is currently no agreed cosmetic series for use across Europe. OBJECTIVES: To establish allergens currently tested in local and national cosmetic series. METHOD: Members of the European Surveillance System on Contact Allergy and the European Cooperation in Science and Technology project TD1206 ("StanDerm") were surveyed to establish their current practice. RESULTS: A wide range of allergens was tested but there was significant variation between centres on the allergens considered to be important in screening for allergy to cosmetics. The number of allergens tested in addition to the baseline series varied between 2 and 50. CONCLUSIONS: There is a need for further investigation to establish the frequency and relevance of reactions to cosmetic allergens to enable an agreed evidence-based cosmetic series to be produced. Criteria for inclusion need to be established.

Adding sorbitan sesquioleate to the European baseline series: Necessary, reasonable, or unavoidable?

Positive reactions to fragrance mix I (FM I) are frequent in consecutively patch tested patients suspected of having allergic contact dermatitis. However, the FM I test preparations contain 5% of the emulsifier sorbitan sesquioleate (SSO), and it is well known that SSO can cause contact allergic reactions in its own right. Indeed, the available data show that some patients with contact allergy to SSO react to FM I but are not allergic to fragrances. When SSO is not tested, this situation may go unnoticed, a wrong diagnosis of fragrance allergy may be given to the patient, and unjustified advice to avoid fragrances and fragranced products will be given in such cases. To avoid such suboptimal patient care, we postulate that testing with SSO in all patch tested individuals is mandatory. As it is well known that only a minority of FM I-reactive patients will undergo a breakdown test with the ingredients and SSO, testing with SSO in all patients can only be achieved by adding it to the European baseline series. Not testing with SSO may also result in misinterpretation of patch test reactions to Myroxylon pereirae resin and 2-hydroxyethyl methacrylate in the baseline series, as both (may) contain SSO, and, for the same reason, of reactions to several other hapten test materials.

Allergic contact dermatitis caused by topical ophthalmic medications: Keep an eye on it!

BACKGROUND: Allergic contact dermatitis (ACD) caused by topical ophthalmic medications is often overlooked. OBJECTIVES: To study the demographic characteristics, lesion locations and associated medical conditions of the patients with ACD caused by ophthalmic drugs, and to identify the most common allergenic culprits, as well as trends in frequencies over the years. METHODS: From January 1990 until December 2016, 16 065 patients were investigated in our clinic; all patients with a positive patch test reaction to an eye medication or its ingredient(s) having caused ACD were assessed. For each allergen identified, the number of positive test results as compared with the total number of those in the total population, as well as trends across three periods, namely 1990 to 1998, 1999 to 2007, and 2008 to 2016, were studied. RESULTS: One hundred and eighteen patients (0.7%) presented with positive patch test reactions to ingredients of and/or topical ophthalmic medications. Aminoglycoside antibiotics, followed by corticosteroids, as pharmacologically active ingredients, as well as wool alcohols, thiomersal, and benzalkonium chloride, as excipients, were the most frequent culprits. Chloramphenicol showed a decreasing trend of positive reactions over time, whereas reactions to tobramycin increased. CONCLUSION: ACD caused by eye medication is mainly attributable to active principles, but other excipient ingredients, beside the products "as is," should be tested as well.

Concomitant contact-allergic reactions to iodopropynyl butylcarbamate and iodine.

BACKGROUND: Iodopropynyl butylcarbamate (IPBC) is a broad-spectrum preservative for use in several product types, including cosmetics, in which its concentrations have been limited by EU legislation because of concerns related to its iodine content and release, and the risk of subsequent iodine overdose. OBJECTIVES: To report on concomitant patch test reactions observed with iodine and IPBC in patients sensitized to iodine-containing antiseptics. PATIENTS: Between 2012 and 2018, seven patients, six from Belgium and one from France, two suffering from acute dermatitis during surgical interventions, four from dermatitis caused by wound treatment, and one from occupational dermatitis, were shown to be sensitized to iodine and/or povidone-iodine (PVP-I), which was considered to be relevant for their dermatitis. All patients were coincidentally also patch tested with IPBC. RESULTS: All patients showed positive patch test reactions to several other allergens, including IPBC. No relevance could be detected for IPBC. CONCLUSIONS: We suspect that, notwithstanding the absence of firm evidence for IPBC being dehalogenated to produce free iodine in animals or in humans, the patch test reactions to IPBC in iodine-allergic subjects were possibly caused by free iodine released from this preservative agent, thus underlining the EU restrictions regarding the use of this preservative in cosmetics.

Allergic contact dermatitis caused by isobornyl acrylate in the Enlite glucose sensor and the Paradigm MiniMed Quick-set insulin infusion set.

BACKGROUND: The FreeStyle Libre glucose sensor has caused many cases of allergic contact dermatitis, and isobornyl acrylate (IBOA) in this sensor has been identified as one of the culprit allergens. OBJECTIVES: To report on the presence of IBOA in devices produced by Medtronic, namely, the Enlite sensor and the insulin infusion set Paradigm MiniMed Quick-set. PATIENTS AND METHODS: Five patients reacting to the glucose sensor Enlite and/or the insulin infusion set Paradigm MiniMed Quick-set observed in three clinics (two Belgian and one Swedish) were patch tested with the baseline and other series, as well as with IBOA; four of them also with pieces of adhesive patches from the devices, and two with a thin layer chromatogram of Enlite glucose sensor extracts. Gas chromatography-mass spectrometry (GC-MS) analyses were performed. RESULTS: Four patients reacted to IBOA and one to colophonium, a known allergen in Enlite, and three to the adhesive part of the sensor or the insulin infusion set. IBOA was identified in the sensor by GC-MS, and its presence was indicated in the infusion set. CONCLUSIONS: IBOA is a contact allergen in Enlite glucose sensor, and likely also in the infusion set. Therefore, these devices are not suitable alternatives for patients sensitized to the FreeStyle Libre sensor.

The preservative 2-(thiocyanomethylthio)benzothiazole: A potential allergen in leather products.

BACKGROUND: Allergic contact dermatitis caused by leather is common, and several responsible allergens, such as tanning agents, glues, mercaptobenzothiazole derivatives, and dyes, but also antimicrobials and antifungals, are involved. MATERIAL AND METHODS: Three female patients were referred to the Departments of Dermatology in a Belgian university hospital following skin reactions caused by leather products (shoes, belt, and car seats). They were patch tested with the European baseline series and samples of suspected leather products, and additionally with 2-(thiocyanomethylthio)benzothiazole (TCMTB), an antifungal agent previously reported to be a contact allergen in footwear. Chromatographic analyses of samples of all the leather materials tested were performed at the Department of Occupational and Environmental Dermatology in Malmö, Sweden. RESULTS: The patients reacting to the leather samples were shown to be sensitized to TCMTB, the presence of which could be confirmed by chemical analyses of samples obtained from the patients. CONCLUSION: Patch tests with TCMTB should be considered in patients with contact dermatitis caused by leather items.

Unexpected positive patch test reactions to sesquiterpene lactones in patients sensitized to the glucose sensor FreeStyle Libre.

BACKGROUND: Most diabetic patients sensitized to FreeStyle Libre react to isobornyl acrylate (IBOA), with a considerable number of them also showing unexpected positive patch test reactions to sesquiterpene lactone (SL) mix (SLM) tested in the baseline series. OBJECTIVES: To compile patch test results of subjects affected, and provide potential explanations for this association. PATIENTS AND METHODS: Fifty-three Freestyle Libre-allergic patients were patch tested with IBOA and/or SLM, and several were also patch tested with the components of SLM. Chromatographic analyses were performed on the glucose sensor, IBOA, and the components of SLM. RESULTS: Thirty-three patients reacted positively to the components of SLM, and 11 of 27 patients reacted positively to alantolactone, in particular. Gas chromatography-mass spectrometry (GC-MS) analyses did not detect these chemicals in the different parts of the glucose sensor, or in IBOA. CONCLUSION: Significant co-sensitizations between SLs on the one hand and the glucose sensor FreeStyle Libre and/or isobornyl acrylate on the other hand exist, without evidence of the presence of SLs via GC-MS analysis. Cross-reactions between them seem improbable. As a possible hypothesis, a common precursor for both, such as camphene, may exist.

Allergic contact dermatitis caused by calcipotriol.

BACKGROUND: Calcipotriol, a synthetic vitamin D analogue, is widely used for the topical treatment of psoriasis. It often causes irritant reactions, whereas allergic contact dermatitis has less commonly been reported. OBJECTIVES: To report on 6 patients (among them an 11-year-old child) who presented with eczematous lesions complicating pre-existing dermatitis, observed in our tertiary referral patch test clinic between 2004 and 2016. METHODS: Patch tests were performed with the commercial preparation used by the patients and/or its ingredients, including calcipotriol (2 or 10 µg/ml in isopropyl alcohol), according to ESCD patch test guidelines. RESULTS: Allergic contact dermatitis was confirmed in all cases, and the lesions improved following treatment with topical corticosteroids and/or oral medication. CONCLUSIONS: When topical treatment with calcipotriol fails to improve, or even worsens, existing skin lesions, contact allergy should be suspected. A patch test concentration of 2 µg/ml in isopropyl alcohol seems to be the most suitable. According to the literature, patients sensitized to calcipotriol may tolerate topical therapy with other vitamin D3 analogues, particularly tacalcitol.