Contact Allergy to Allergens in the Swedish Baseline Series Overrepresented in Diabetes Patients with Skin Reactions to Medical Devices - A Retrospective Study from Southern Sweden.

Allergic contact dermatitis is reported among individuals using continuous glucose monitoring systems and insulin pumps. The aim of this study was to describe contact allergy patterns for allergens in the Swedish baseline series and medical device-related allergens among users. Contact allergy to baseline series allergens and isobornyl acrylate was compared between diabetes patients and dermatitis patients patch-tested at the Department of Occupational and Environmental Dermatology during 2017 to 2020. Fifty- four diabetes patients and 2,567 dermatitis patients were included. The prevalence of contact allergy to fragrance mix II and sesquiterpene lactone mix was significantly higher in diabetes patients compared with dermatitis patients. Of the diabetes patients 13.0% and of the dermatitis patients 0.5% tested positive to sesquiterpene lactone mix (p < 0.001). Of the diabetes patients 7.4% and of the dermatitis patients 2.3% tested positive to fragrance mix II (p = 0.041). Of the diabetes patients 70.4% tested positive to medical device-related allergens. Of the diabetes patients 63.0% and of the dermatitis patients 0.2% were allergic to isobornyl acrylate (p < 0.001). In conclusion, not only medical device-related contact allergies, but also contact allergy to baseline series allergens (fragrance mix II and sesquiterpene lactone mix), is overrepresented in diabetes patients who use medical devices.

Patterns of simultaneous contact allergies in patients with contact sensitization to oxidised linalool and oxidised limonene.

BACKGROUND: Contact allergy rates of linalool and limonene hydroperoxides (HPs) have increased. OBJECTIVES: To demonstrate the patterns of simultaneous positive patch test (PT) reactions and prevalences of multiple contact allergies (MCAs) in patients with contact allergy to linalool and/or limonene HPs. METHODS: A retrospective analysis of consecutive dermatitis patients in 2015-2020 was performed. RESULTS: Of all 4192 patients, 1851 had at least one positive PT reaction. Of these, 410 (22.2%) had MCAs, significantly related to a higher age (p-value = 0.003). Patients with an exclusively positive reaction to linalool HPs but not limonene HPs were shown to have MCAs (p-value <0.001, odds ratio (95% confidence interval) = 4.15 (3.01-5.73)). Patients with simultaneous contact allergies to both linalool and limonene HPs had contact allergies to many other screening and fragrance allergens. CONCLUSIONS: Simultaneous positive PT reactions to allergens in baseline series and fragrances are common in patients with the HPs contact allergy, especially linalool HPs. The pattern of simultaneous PT reactions principally suggested the co-sensitization of the cosmetic allergens.

New device, 'old' allergens. Allergic contact dermatitis caused by the Dexcom G7 glucose sensor.

BACKGROUND: Allergic contact dermatitis (ACD) has been reported as an adverse effect from the use of several glucose sensors and insulin pumps from different manufacturers. Isobornyl acrylate (IBOA) has been identified as a major culprit sensitizer, but also other acrylates and (modified) colophonium have been reported as causes of ACD. OBJECTIVES: To report the two first cases diagnosed with ACD caused by the Dexcom G7 (DG7) glucose sensor. PATIENTS AND METHODS: Two children with suspected ACD from DG7 were patch tested with our medical device series with an addition of selected test preparations including two variants of modified colophonium - methyl hydrogenated rosinate (MHR) and glyceryl hydrogenated rosinate (GHR). Both patients were also tested with acetone extracts made from different parts of the DG7 sensor. The extracts were analysed by gas chromatography-mass spectrometry (GC-MS). RESULTS: Both patients tested positive to IBOA, hydroabietyl alcohol and GHR. In addition, patient 1 had a positive reaction to MHR and patient 2 had a positive reaction to colophonium. The GC-MS analyses showed the presence of IBOA and colophonium-related substances in the DG7 extracts. CONCLUSIONS: Both patients were diagnosed with contact allergy to well-known medical device-related sensitizers. The presence of IBOA and (modified) colophonium in a newly introduced (on the Swedish market in 2023) glucose sensor is remarkable and indicates an inadequate toxicological assessment of the materials used in the sensor.

Allergic contact dermatitis due to 1,6-hexanediol diacrylate in ostomy patients.

BACKGROUND: Many people live with ostomies after life-saving surgery. Ostomy patients often suffer from peristomal dermatitis. Allergic contact dermatitis (ACD) has been reported, mostly due to contact allergy (CA) to topical agents. OBJECTIVES: We present three patients with therapy resistant peristomal dermatitis, suggesting ACD caused by different stoma products. METHODS: Patch testing was performed with baseline series, additional series, and selected allergens. They were also tested with their own ostomy products as is and separate extracts of the products. Extracts were analysed using Gas Chromatography-Mass Spectrometry (GC-MS). RESULTS: In all three patients we diagnosed CA to 1,6-hexanediol diacrylate (HDDA), +++ in case (C) 1 and 3, ++ in C 2. HDDA was detected in C 2's ostomy pouch adhesive and in C 1's and 3's flange extenders used to improve the adhesion of the ostomy pouches. CONCLUSION: Therapy resistant peristomal dermatitis should always be suspected of ACD and patch testing, especially with the patient's own products, should be performed.

Contact allergy to oxidised geraniol may be over-represented in individuals with photocontact allergy to ketoprofen.

BACKGROUND: Simultaneous overrepresentations of contact allergies and photocontact allergies are common in individuals with photocontact allergy to ketoprofen. AIMS: To investigate whether contact allergy to oxidised (ox.) geraniol, geraniol, geranial, neral and citral is overrepresented in individuals with photocontact allergy to ketoprofen. METHODS: The contact allergy rates to ox. geraniol, geraniol, geranial, neral and citral in routinely patch tested dermatitis patients were compared with the corresponding rates in individuals with photocontact allergy to ketoprofen. RESULTS: Allergic patch test reactions were noted to ox. geraniol 11% (n = 39, 5.8%), ox. geraniol 6% (n = 12, 1.8%), geraniol 6% (n = 2, 0.3%), geranial (n = 18, 2.7%), neral (n = 7, 1.0%) and citral (n = 15, 2.2%). In those four patients who were diagnosed with photocontact allergy to ketoprofen during the test period, a significant overrepresentation (p = 0.020) of simultaneous contact allergy to ox. geraniol 11% was demonstrated. Overrepresentation of simultaneous contact allergy to various combinations of ox. geraniol, ox. limonene and ox. linalool was also noted in ketoprofen-photoallergic patients. CONCLUSIONS: Contact allergy to ox. geraniol, geranial and citral is common in routinely tested dermatitis patients. There is an overrepresentation of simultaneous contact allergy to ox. geraniol, ox. limonene and ox. linalool in patients with photocontact allergy to ketoprofen.

Use of sorbitan sesquioleate in patch test preparations and patch testing with the substance-What do our results mean?

BACKGROUND: Sorbitan sesquioleate (SSO) is a sorbitan fatty acid ester, an emulsifier used in topical products and certain patch test preparations. SSO may affect the patch test results. It has been debated whether to include the substance in the baseline series to avoid misinterpretation of the results. OBJECTIVES: To report the prevalence and simultaneous reactions of SSO with other patch test preparations containing SSO as an emulsifier. MATERIALS AND METHODS: A retrospective analysis of 3539 dermatitis patients who underwent patch testing from 2016 to 2020 was performed. RESULTS: The 5-year SSO contact allergy prevalence was 0.48%, and 1.3% had a doubtful reaction. Patients with a stronger positive reaction (2+, 3+) were more likely to react simultaneously to other allergen preparations containing SSO (p value = 0.018). One patient with a strong reaction to SSO reacted positively to all SSO-containing patch test preparations. Definite fragrance allergens could not be identified in the patients who had simultaneous reactions to SSO and fragrance mix (FM) I. CONCLUSIONS: Patch testing with allergen preparations containing SSO affected the patch test interpretation. Fragrance contact allergy could not be ruled out when a patient simultaneously reacted to SSO and FM I. Changing emulsifiers in patch test preparations would be advantageous.

4,4'-Thiobis(2-tert-butyl-5-methylphenol), an antioxidant in medical devices that may cause allergic contact dermatitis.

BACKGROUND: Antioxidants in medical devices, added to protect polymers or adhesives, may also cause contact dermatitis in some individuals. OBJECTIVES: To present data on sensitization to 4,4'-thiobis(2-tert-butyl-5-methylphenol), an antioxidant detected in some types of medical devices, for six patients that experienced eczematous reactions to different medical devices. METHODS: Patch testing with 4,4'-thiobis(2-tert-butyl-5-methylphenol), 1% pet was performed. Gas chromatography-mass spectrometry (GC-MS) was used for identification of 4,4'-thiobis(2-tert-butyl-5-methylphenol) in different medical device products. RESULTS: Six patients with contact allergy to 4,4'-thiobis(2-tert-butyl-5-methylphenol) also had relevant contact allergic reactions to medical devices containing the antioxidant. The presence of the antioxidant in products was detected using GC-MS analysis. CONCLUSIONS: The antioxidant 4,4'-thiobis(2-tert-butyl-5-methylphenol) may cause allergic contact dermatitis after exposure to different medical devices.

Allergic reactivity for different dilutions of eugenol in repeated open application test and patch testing.

BACKGROUND: Eugenol is a known contact sensitiser included in fragrance mix I. OBJECTIVE: To assess the allergic reactivity to eugenol in different concentrations using patch test as well as repeated open application test (ROAT). METHODS: Overall 67 subjects from 6 European dermatology clinics participated in the study. The ROAT was performed for 21 days twice a day, applying 3 dilutions of eugenol (2.7%-0.5%) and a control. Before and after the ROAT, patch testing with 17 dilutions of eugenol (2.0%-0.00006%) and controls was performed. RESULTS: Out of the 34 subjects with contact allergy to eugenol, 21 (61.8%) showed a positive patch test before ROAT was performed, the lowest positive concentration was 0.031%. The ROAT was positive in 19 (55.9%) of the 34 subjects, the time until a positive reaction occurred was negatively associated with the concentration of the ROAT solution, as well as with the allergic reactivity of the subjects as defined by patch testing. In the patch test after ROAT, 20 of the 34 test subjects (58.8%) showed a positive reaction. In 13 (38.2%) of the 34 test subjects, the patch test result was not reproduceable, still 4 (31.0%) of these 13 subjects developed a positive ROAT. CONCLUSION: Eugenol can provoke a positive patch test reaction in a very low dose; besides, this hypersensitivity may persist even if a former positive patch test is not reproduceable.

Contact dermatitis in children caused by diabetes devices.

BACKGROUND: Insulin pumps and glucose monitoring devices improve diabetes mellitus control and enhance patients' quality of life. However, a growing number of adverse cutaneous reactions related to the use of these devices have been reported. OBJECTIVE: To investigate the culprits of localized contact dermatitis in paediatric patients with diabetes caused by insulin pumps and glucose monitoring devices. METHODS: Retrospective analysis of 15 paediatric patients patch tested as part of a clinical investigation for skin reactions associated with insulin pumps and glucose monitoring devices. RESULTS: Seven patients had positive patch test reactions to isobornyl acrylate (IBOA) and five had positive reactions to benzoyl peroxide (BP). Positive patch test reactions to materials from the glucose sensor and/or insulin pump were seen in 10 of the 15 patients. Three had positive reactions to adhesive remover wipe from Smith and Nephew Remove and four had reactions to EMLA plaster. CONCLUSION: A high share of patients showed positive reactions to IBOA and/or their medical devices (insulin pumps or glucose devices). A third of patients showed positive reactions to BP. The presence of additional unidentified allergens cannot be excluded, highlighting the importance of access to a full description of the chemical composition of the devices.

Simultaneous patch testing with fragrance markers in the baseline series and the ingredients of fragrance mixes: An update from southern Sweden.

BACKGROUND: Regularly updating the prevalence of fragrance contact allergy (CA) is important. Patch testing with fragrance markers in the baseline series and the ingredients of fragrance mixes (FMs) is still debated. OBJECTIVES: To update the prevalence and clinical characteristics of patients with fragrance CA. To establish the results of patch testing with individual allergens of FMs. METHODS: A retrospective analysis of 3539 patients with dermatitis who were patch tested with the baseline series and FMs ingredients during 2016 to 2020 was performed. RESULTS: The prevalence of fragrance CA was 13%. About 10% of these patients with fragrance CA would be missed if the individual ingredients were not tested. Unlike hydroxyisohexyl 3-cyclohexene carboxaldehyde, there was no decreasing trend of CA to Evernia prunastri (oakmoss) extract after the EU regulation came into force. Patients with CA from only one ingredient of the mixes or having a weak positive reaction to the ingredients were significantly missed when tested with only the fragrance markers in the baseline series. CONCLUSIONS: Patch testing with individual fragrance allergens is crucial for experts to expand knowledge in the fragrance CA field. The concentrations of the allergens in FMs may need to be adjusted to detect patients with fragrance CA, since some were significantly overlooked.

Contact allergy to oxidized linalool and oxidized limonene: Patch testing in consecutive patients with dermatitis.

BACKGROUND: Contact allergy to oxidized (ox.) linalool and ox. limonene has been reported to have a high prevalence, raising the question of inclusion into the baseline series. However, several important issues should be clarified and further investigated before inclusion can be warranted. OBJECTIVES: To report the trends of ox. terpenes allergy in patients with dermatitis, features of the patch test reactions, and clinical characteristics of the patients. METHODS: A retrospective analysis of 5773 patients was performed. All patients were patch tested with baseline series, individual ingredients of fragrance mix I and II, ox. linalool, and ox. limonene from 2013 to 2020. RESULTS: The prevalence rates of contact allergy to ox. linalool and ox. limonene were 7.0% and 5.1%, respectively. Significantly increasing trends of contact allergy were observed. More than 95% of contact allergy cases were identified on Day 3/4. Patients with contact allergy to ox. linalool and ox. limonene were significantly younger than those with contact allergy to other fragrances and were predominantly female. Strong reactions were associated with older age and multiple fragrance allergies. CONCLUSIONS: Contact allergy to ox. linalool and ox. limonene is becoming increasingly important, and findings show intriguing features. More studies concerning the clinical relevance before recommending these substances for screening are required.

Outbreak of occupational allergic contact dermatitis from a smartphone screen protector glue.

BACKGROUND: Sensitization to acrylates is a concern in the occupational/environmental dermatology field. OBJECTIVE: To describe an occupational allergic contact dermatitis (ACD) outbreak from a smartphone screen protector glue. METHODS: Thirteen affected workers of a chain store selling phone screen protectors were investigated in five Spanish dermatology departments. The glue datasheet and label were assessed. A chemical analysis of the glue was performed. Based on this, some patients underwent additional testing. RESULTS: All patients (all female, mean age: 25) had severe fingertip dermatitis. The datasheet/label indicated that the glue contained isobornyl acrylate (IBOA), a "photoinitiator" and polyurethane oligomer. The company informed us that the ingredients were polyurethane acrylate, "methacrylate" (unspecified), acrylic acid, hydroxyethyl methacrylate, propylmethoxy siloxane, and photoinitiator 184. Isobornyl acrylate (or IBOA) and N,N-dimethylacrylamide (DMAA) were patch tested in eight and two cases, respectively, with negative results. A chemical analysis revealed 4-acryloylmorpholine (ACMO); isobornyl methacrylate (IBMA), and lauryl acrylate in one glue sample. Seven patients were patch tested with dilutions of the identified substances and six of seven were positive for ACMO 0.5% pet. CONCLUSION: An outbreak of occupational ACD, likely from ACMO in a glue is described. Further investigations are needed to corroborate the role played by each compound identified in the chemical analyses.

Contact Allergy to Oxidized Linalool and Oxidized Limonene is Over-represented in Individuals with Photocontact Allergy to Ketoprofen.

Simultaneous contact allergies are common in individuals with photocontact allergy to ketoprofen. The rate of contact allergy to the fragrance substances oxidized linalool and oxidized limonene in ketoprofen-photo-allergic individuals were investigated in comparison with the corresponding rates in individuals without photo-contact allergy to ketoprofen, using Fisher's exact test. A total of 4,021 patients were routinely tested with oxidized linalool; of whom 190 (4.7%) tested positively. For oxidized limonene the numbers were 3,797 patients and 111 positive reactions (2.9%). A total of 19 contact allergic reactions to oxidized linalool were noted in 29 patients (65.5%) who also had photocontact allergy to ketoprofen (p < 0.0001). The corresponding figures for oxidized limonene were 10 positive reactions in 24 ketoprofen-photoallergic individuals (41.7%) (p < 0.0001). Contact allergy to oxidized linalool and/or oxidized limonene is common in routinely tested patients with dermatitis and, particularly, in those patients who are photoallergic to ketoprofen.

Contact allergy to fragrance mix I and its components in individuals with photocontact allergy to ketoprofen.

BACKGROUND: Contact allergy to fragrance mix I (FM I) is over-represented in patients photoallergic to ketoprofen. The prevalence of contact allergy to two components of FM I, cinnamal and cinnamyl alcohol, in ketoprofen-photoallergic patients is higher than in dermatitis patients. OBJECTIVE: To explore the prevalence of contact allergy to FM I and its individual components in patients with photocontact allergy to ketoprofen, and to compare with a dermatitis and the general population. METHODS: Data on patch and photopatch tests performed between 2009-2018 were collected. Ketoprofen-photoallergic patients were compared with dermatitis patients and published data on the general population regarding the prevalence and the distribution of contact allergy to FM I and its components. RESULTS: A higher prevalence of contact allergy to cinnamyl alcohol compared with cinnamal (23.3% vs 10.0%), and eugenol compared with isoeugenol (23.3% vs 6.7%), was observed in ketoprofen-photoallergic patients, while the relationship was the opposite in the dermatitis group (0.7% vs 1.05%; 0.4% vs 0.9%). The overall prevalence of contact allergy to several components of FM I was significantly higher in ketoprofen-photoallergic patients. CONCLUSIONS: Contact allergy to FM I and many of its components is over-represented in patients photoallergic to ketoprofen compared with dermatitis patients and the general population.

Changes in adhesive ingredients in continuous glucose monitoring systems may induce new contact allergy pattern.

BACKGROUND: Medical devices (MD) in close skin-contact for a prolonged time, such as glucose monitoring (CGM) systems, are a risk factor for contact allergy, and there has been an increase in patients using these. Correct diagnosis demands targetted testing. OBJECTIVES: We report a new allergen in a continuous CGM system in which the adhesive was changed. The allergy pattern of the patients diagnosed is reported. METHODS: The three patients reported were patch tested with an MD series, own material, and possible allergens found through analysis with gas chromatography-mass spectrometry, comparing analysis from the CGM system before and after change. RESULTS: The patients were sensitized to isobornyl acrylate (IBOA), found in previously used devices and the present CGM. Apart from IBOA, the culprit allergen was found to be 2,2'-methylenebis(6-tert-butyl-4-methylphenol) monoacrylate. CONCLUSION: Allergic contact dermatitis due to CGM systems and insulin pumps are difficult to investigate and require chemical analysis. Because of the lack of information on substances used in the production, and when changes with MDs are initiated, it is difficult to advise patients, especially since they risk sensitization to several allergens. The use of MDs has increased and, thus, the need for collaboration between manufacturers, clinicians, and patient organizations.

A comparative study between the two patch test systems Finn chambers and Finn chambers AQUA.

BACKGROUND: Finn Chambers AQUA (FCA) is a development of the Finn Chambers (FC) test system in which the test chambers are mounted on a moisture-resistant adhesive patch. FCA has pre-fixed filter papers. Because the use of FCA does not require any extra taping or use of separate filter papers, a change from FC to FCA chambers may be beneficial for both patients and patch test technicians. OBJECTIVES: To investigate whether there are any differences regarding detection of contact allergy when simultaneous patch testing is performed with FC and FCA. MATERIALS AND METHODS: Results from 434 dermatitis patients simultaneously tested with 10 allergens in both FC and FCA were evaluated. RESULTS: There were no significant differences regarding detection of positive reactions between the two test systems. There were significantly more doubtful reactions to methylisothiazolinone, fragrance mix I and hydroperoxides of linalool when testing with FCA. We only observed significantly more doubtful reactions in FC regarding nickel(II)sulfate. Irritant reactions to formaldehyde were also significantly more common when using FCA. CONCLUSION: The FC and FCA had good agreement in detection of positive reactions. However, the results including doubtful and irritant reactions justify further research regarding optimization of the dose.

Contact dermatitis from glucose sensors in Spain: A multicentric approach.

BACKGROUND: Allergic contact dermatitis from glucose sensors may interfere with their ongoing application. OBJECTIVE: To evaluate a series of Spanish patients with contact dermatitis to glucose sensors regarding former sources of contact allergens, patch test results, and outcomes from the ongoing use of the device. METHODS: A series of patients with contact dermatitis from glucose sensors was investigated in eight dermatology departments across Spain (epidemiological features, brands, latency time to develop dermatitis, the ability to continue using the devices as well as the patch test results). RESULTS: Thirty patients were evaluated (mean age 20.9 years). A total of 66.7% were children and 66.7% female. Ninety per cent used Freestyle Libre (FSL). Eight of 26 (30.8%) reacted to isobornyl acrylate (IBOA) and two of 20 (10.0%) to N,N dimethylacrylamide (DMAA). The mean latency time to develop dermatitis was 9 months. Sixteen of 29 (55.2%) patients continued using the same sensor causing the reaction. Thirteen of 29 (44.8%) patients were unable to continue using the sensor because of severe reactions. Of these, five were positive to IBOA, one to IBOA and DMAA, one to DMAA, one to colophony, and one to isopropyl alcohol wipes. In one patient, the outcome was unknown. CONCLUSION: The frequency of sensitisation to IBOA and DMAA, was lower than in other European series, but similar to a previously published Spanish article. Legislation requiring manufacturers to provide information regarding the composition of medical devices and cooperate with the investigations into contact dermatitis is urgently needed.

Can reducing cosmetic substances help prevent chromate contact allergy?

BACKGROUND: Allergic contact dermatitis caused by Cr(VI) is often severe and difficult to treat. Therefore, primary prevention is a main goal but, secondary prevention can be valuable to ease the symptoms or prevent relapse of Cr(VI) dermatitis when sensitization has occurred. Barrier creams have been tried for many chemical substances, but until now there is no successful barrier cream against Cr(VI). OBJECTIVES: To investigate the ability of reducing agents to transform Cr(VI) into Cr(III) in an experimental situation, in order to find suitable chemicals to investigate for possible use in a barrier cream. METHODS: The capacity to reduce the amount of Cr(VI) was analyzed in water solutions of acetylcysteine, cysteine, dihydroxyacetone, glutathione, and iron sulfate heptahydrate. Thereafter the reducing capacity of acetylcysteine, dihydroxyacetone, glutathione, and iron sulfate on the amount of Cr(VI) in cement extracts was investigated. The content of Cr(VI) in the test solutions and in the cement extracts was estimated by the diphenyl carbazide spot test. RESULTS: All of the chosen chemicals reduced the amount of Cr(VI) in the test solutions and in the cement extracts to some extent. The reducing capacity was most prominent for iron sulfate. CONCLUSION: A reducing capacity was found for all chosen chemicals.

Skin application of glutathione and iron sulfate can inhibit elicitation of allergic contact dermatitis from hexavalent chromium.

BACKGROUND: Allergic contact dermatitis (ACD) caused by hexavalent chromium, Cr(VI), is often severe and difficult to treat. The most common source of exposure to Cr(VI) in Sweden used to be cement, and more recently leather. The contact allergy can be diminished or inhibited if the exposure is decreased or ceases. Barrier creams against different kinds of allergens have been investigated for their protective properties which may offer protection against Cr(VI) exposure. OBJECTIVES: To investigate the capacity of formulas containing glutathione (GSH) and iron sulfate to inhibit elicitation of ACD in Cr(VI)-allergic individuals when exposed to Cr(VI). METHODS: In 18 Cr(VI)-allergic volunteers the back was divided into eight patch test areas which were treated with preparations of possible barrier creams, prior to patch testing with a dilution series of potassium dichromate and a buffered extract of cement. RESULTS: A significant reduction in reactivity to Cr(VI) and cement extract on skin treated with formulas containing GSH or iron sulfate was noticed, compared with untreated skin. CONCLUSION: Formulas containing GSH or iron sulfate in barrier creams inhibit ACD in individuals allergic to Cr(VI) when applied before exposure to Cr(VI) and cement extract.

Contact dermatitis caused by glucose sensors-15 adult patients tested with a medical device patch test series.

BACKGROUND: Several cases of allergic contact dermatitis (ACD) to the glucose sensor FreeStyle Libre have been reported. Isobornyl acrylate (IBOA) and N,N-dimethylacrylamide (DMAA) are known culprit allergens. OBJECTIVES: To evaluate patients with suspected ACD to FreeStyle Libre in a standardized manner, present causative allergens, and assess patient-reported implications. METHODS: A total of 15 patients with suspected ACD to FreeStyle Libre were patch tested with the Swedish baseline series and a new medical device series. IBOA and DMAA were tested at 0.1% and 0.3% in petrolatum (pet.). Readings were performed on day (D) 3 and D7. Background data, details on skin reactions, and associated implications were assessed using a questionnaire. RESULTS: Thirteen patients were sensitized to IBOA and four to DMAA. Two positive reactions to IBOA and one to DMAA were seen only at 0.3% concentration on D7. Median duration of sensor use before dermatitis onset was 6 months. Half the number of the patients took precautions in everyday life due to sensor-related skin reactions. Six patients discontinued sensor usage. CONCLUSIONS: Patients with suspected ACD to glucose sensors should be evaluated with a relevant patch test series containing IBOA and DMAA. Adding the 0.3% pet. concentration is recommended. The reading on D7 is necessary.