Fragrance Contact Allergy - A Review Focusing on Patch Testing.

Fragrance materials are widely used in various types of products in daily life and many of them can be contact sensitizers. Contact allergy to fragrances has been reported to be common worldwide. Unlike other groups of contact allergens such as metals and preservatives, fragrance materials in consumer products can be present as single fragrance chemicals or in the form of mixtures known as natural complex substances. Due to the complexity of the fragrance materials and the high number of fragrance substances known to cause contact sensitization, selecting suitable materials for patch testing is challenging. Emerging fragrance markers have been additionally introduced in different baseline series for screening to enhance the rate of fragrance contact allergy detection. Moreover, there have been continual updates on basic knowledge, clinical perspectives, sources of exposure, and regulations on the use of fragrance materials. Avoiding pitfalls while performing patch testing with fragrance test materials is also crucial and should not be overlooked. Therefore, this review aims to update knowledge to provide a high-quality holistic approach to fragrance contact allergy diagnosis and management.

Eyelid dermatitis in patch-tested adult patients: a systematic review with a meta-analysis.

Eyelid dermatitis (ED) affects a cosmetically significant area and leads to patients' distress. Despite ongoing and recent research efforts, ED remains a multidisciplinary problem that needs further characterization. We aimed to evaluate the atopic eyelid dermatitis (AED) frequency in ED patients and to perform their clinical profiling. PubMed databases were searched from 01.01.1980 till 01.02.2024 to PRISMA guidelines using a search strategy: (eyelid OR periorbital OR periocular) AND (dermatitis or eczema). Studies with patch-tested ED patients were included. Proportional meta-analysis was performed using JBI SUMARI software. We included 65 studies across Europe, North America, Asia and Australia, with a total of 21,793 patch-tested ED patients. AED was reported in 27.5% (95% CI 0.177, 0.384) of patch-tested ED patients. Isolated ED was noted in 51.6% (95% CI 0.408, 0.623) of 8453 ED patients with reported lesion distribution, including 430 patients with isolated AED. Our meta-analysis demonstrated that the AED frequency in patch-tested ED patients exceeded the previous estimate of 10%. Isolated AED was noted in adult patients, attending contact allergy clinics. Future studies are needed to elucidate the global prevalence and natural history of isolated AED in adults.

Nine years of patch testing with isocyanates in a clinic of occupational dermatology.

BACKGROUND: Isocyanates are used as starting materials of polyurethane (PU) products. They are relatively important occupational skin sensitizers. OBJECTIVES: To analyse results of a large isocyanate patch test series of 19 isocyanate test substances and 4,4'-diaminodiphenylmethane (MDA), a marker of 4,4'-diphenylmethane diisocyanate (MDI) hypersensitivity. METHODS: Test files were screened for positive reactions in the isocyanate series. Patients with positive reactions were analysed for occupation, exposure and diagnosis. RESULTS: In 2010-2019, 53 patients had positive reactions in the series (16% of 338 patients tested). MDA, the well-established screening substance for MDI allergy, was positive in 30 patients, an in-house monomeric MDI test substance in 23 patients and 3 different polymeric MDI test substances in 19-21 patients. We diagnosed 16 cases of occupational allergic contact dermatitis (OACD) from MDI including 3 pipe reliners. Hexamethylene-1,6-diisocyanate (HDI) oligomers in paint hardeners caused 5 cases of OACD, more cases than 2,4-toluene diisocyanate (TDI; n = 3) and isophorone diisocyanate (IPDI; n = 1) put together. CONCLUSIONS: In contrast to previous studies, polymeric MDI test substances were not superior to a monomeric MDI. Pipe reliners may get sensitised not only by epoxy products and acrylates but also by MDI in hardeners of PU pipe coatings. HDI oligomers were the second most important causes of OACD after MDI.

A re-assessment of the value of markers of corticosteroid contact allergy in the Spanish baseline series: Clobetasol propionate in the spotlight.

BACKGROUND: Budesonide and tixocortol pivalate as markers of contact allergy to corticosteroids have been questioned, as they are not able to detect a significant percentage of allergic patients. OBJECTIVES: To investigate the potential role of clobetasol propionate in enhancing corticosteroid sensitisation detection. METHODS: Between January 2022 and December 2023, patients who attended centres involved in the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy were tested with an extended baseline series that included budesonide, tixocortol pivalate, clobetasol propionate 0.1% in ethanol and 1% in petrolatum. RESULTS: A total of 4338 patients were tested. Twenty-four patients were allergic to budesonide (0.55%, 95% CI: 0.37-0.82); nine patients were allergic to tixocortol pivalate (0.21%, 95% CI: 0.11-0.39); and 23 patients were allergic to clobetasol (0.53%, 95% CI: 0.35-0.79). Only four of those patients allergic to clobetasol were detected by budesonide and one by tixocortol pivalate. No significant differences in the number of positive tests were found between clobetasol in petrolatum or ethanol. CONCLUSIONS: In Spain budesonide remains the main corticosteroid allergy marker whereas the role of tixocortol pivalate is questionable. The addition of clobetasol propionate to the Spanish baseline series would improve the ability to detect patients allergic to corticosteroids.

Evaluation of atopic diseases in patients with allergic contact dermatitis.

Background: There is controversy on whether allergic contact dermatitis (ACD) is associated with atopy. Research on eczema and the risk of ACD is mixed, and there is sparse literature on other atopic conditions. Objective: Our study examined the prevalence of several atopic conditions, including allergic rhinitis, eczema, asthma, and food allergies in patients with ACD, and compared these to patients without ACD. Methods: We retrospectively reviewed adult patients ages ≥ 18 years with ACD (n = 162) with positive patch testing results and documented any history of atopy, including childhood eczema, asthma, allergic rhinitis, and immunoglobulin E-mediated food allergy. The prevalence of atopic conditions was compared between our ACD cohort and controls without ACD (n = 163) from our electronic medical records system (age and gender matched). Results: Among our patients with ACD, 53 (33%) had allergic rhinitis, 22 (14%) had childhood eczema, 32 (20%) had asthma, and 8 (5%) had food allergies. We observed that the odds of atopy overall (n = 76) in the ACD group compared with the control group were increased (odds ratio [OR] 1.88; p = 0.007). Allergic rhinitis was the highest risk factor (n = 53) with an OR of 12.64 (p < 0.001). Childhood eczema (n = 22) was also increased in the ACD group (OR 2.4; p = 0.026). The odds of asthma and food allergy in the ACD group were also increased; however, the difference was not statistically significant from the control group (OR 1.76 [p = 0.071] and OR 2.76 [p = 0.139], respectively). Conclusion: Patients with ACD had increased odds of eczema, allergic rhinitis, and atopic conditions overall. Asthma and food allergies were not found to have a statistically significant correlation. Larger studies that delve into atopic risk factors in ACD would be important to confirm these findings.

Epidemiological case-control study on contact sensitisation in female foot care specialists with occupational contact dermatitis: Patch test data of the Information Network of Departments of Dermatology (IVDK), 2008 to 2022.

BACKGROUND: Mainly women work as foot care specialists (FCS). They are at risk to develop occupational dermatitis (OD). OBJECTIVES: The objective of this study is to describe the contact sensitisation pattern of female FCS with OD. METHODS: In a retrospective study, patch test and clinical data collected by the Network of Departments of Dermatology (IVDK) from 2008 to 2022 were analysed. Data of 116 female FCS with OD were compared with data of 13 930 female patients with OD working in other professions and 78 612 female patients without OD. RESULTS: Hand dermatitis (93.1%) was significantly more common and face dermatitis (0.9%) significantly less common in female FCS with OD compared to other female patients with or without OD. Frequent suspected allergen sources were disinfectants, gloves, leave-on and nail cosmetics. Occlusion and wetness were important co-factors. The most common diagnoses were irritant contact dermatitis (26.7%) and allergic contact dermatitis (21.6%). No sensitisation to any of the baseline series allergens was significantly more frequent in female FCS with OD than in the two control groups. However, sensitisations to allergens which FCS are abundantly exposed to, including fragrances, preservatives, rubber ingredients and disinfectants, were most common. CONCLUSIONS: FCS should be aware of the OD risk and prevention should be promoted.

Potassium dichromate sensitivity presenting as tefillin dermatitis: A retrospective cohort study.

BACKGROUND: Tefillin are a religious article worn by Jewish men during daily prayer. Tefillin dermatitis secondary to potassium dichromate sensitivity is recognised, but data remain sparse. OBJECTIVE: To investigate the prevalence and clinical characteristics of tefillin dermatitis. METHODS: Patients who underwent patch testing with the European baseline series in a tertiary dermatology clinic in 2009-2023 and were diagnosed with tefillin dermatitis were identified by file review and their clinical data recorded. RESULTS: Of 1679 consecutive male patients tested, 25 (1.49%) were diagnosed with tefillin dermatitis, accounting for 15.34% of all potassium-dichromate-positive patients (163/1679). Mean pre-symptomatic duration of tefillin use was 38 ± 16.9 years, and mean follow-up time, 3.1 ± 2.9 years. Patients presented with an eczematous rash on body areas in direct contact with the leather box or straps of the tefillin. An id reaction was noted in 32%, and sensitivity to other leather accessories, in 44%. Fourteen patients (56%) switched to chromate-free tefillin: symptoms resolved completely in 11 (79%) and partially in 2. LIMITATIONS: Retrospective cohort design. CONCLUSION: This is the largest study to date of tefillin dermatitis caused by sensitivity to potassium dichromate used in leather production. Prognosis after switching to chromate-free tefillin was good-to-excellent. Tefillin dermatitis may be more prevalent than previously thought.

Contact sensitization to fragrance mix I and fragrance mix II among European dermatitis patients: A systematic review.

BACKGROUND: Fragrance substances are a frequent cause of contact allergy worldwide. Fragrance exposure varies by sex, age and possibly country, influenced by cosmetic availability, environmental conditions and cultural practices. OBJECTIVES: To systematically review and gather prevalence of sensitization to fragrance mix I (FM I) and fragrance mix II (FM II) in consecutively patch tested European dermatitis patients. METHOD: A total of 4134 publications on patch test results of European dermatitis patients, published from 1981 to 2022, were systematically reviewed according to a previously registered and published PROSPERO protocol. RESULTS: Eighty-four eligible original articles were analysed. Overall prevalence of sensitization to fragrance mix I (FM I) was 6.81% (95% CI: 6.37-7.28), and FM II was 3.64% (95% CI: 3.3-4.01). Sensitization to FM I was most prevalent in Central and Eastern Europe and to FM II in Western Europe. No clear time trends were observed. Among paediatric dermatitis patients, sensitization prevalence for FM I and FM II was 4.09% (95% CI: 3.37-4.96) and 2.17% (95% CI: 1.53-3.07). CONCLUSION: The frequency of positive patch test results for both FMI and FMII remains high. Sensitization is also prevalent among children. Enhanced regulation and labelling of cosmetic products play a vital role in averting exposure and sensitization to fragrance allergens.

Identification of the pigments used in permanent makeup and their ability to elicit allergic contact dermatitis.

BACKGROUND: Decorative tattoos are known to contain ingredients that may elicit allergic contact dermatitis; it is less well-known if permanent makeup pigments carry the same risk. OBJECTIVE: Identify pigments used in permanent makeup inks sold in the United States and review cases of allergic contact dermatitis to these pigments. METHODS: Using internet searches, permanent makeup inks sold in the United States were identified. Safety data sheets were used to catalog pigments used in permanent makeup. A subsequent literature search was performed to identify cases of allergic contact dermatitis to these pigments. RESULTS: A total of 974 permanent makeup inks were reviewed, and 79 unique pigments were identified. The average product contained 4 pigments. Twenty of the pigments were inorganic metals, including carbon, iron, chromium, manganese, and molybdenum. Fifty-nine pigments were organic, of which most were azo, quinacridone, or anthraquinone dyes. A literature search revealed that 10 of the 79 pigments were associated with allergic contact dermatitis. CONCLUSION: Permanent makeup primarily uses organic pigments, although some metallic pigments are still used. Physicians should also be aware that some of these pigments-both organic and inorganic-are known causes of allergic contact dermatitis. Of note, patch testing to these ingredients can be negative.

Diagnosing contact dermatitis using machine learning: A review.

BACKGROUND: Machine learning (ML) offers an opportunity in contact dermatitis (CD) research, where with full clinical picture, may support diagnosis and patch test accuracy. OBJECTIVE: This review aims to summarise the existing literature on how ML can be applied to CD in its entirety. METHODS: Embase, Medline, IEEE Xplore, and ACM Digital Library were searched from inception to February 7, 2024, for primary literature reporting on ML models in CD. RESULTS: 7834 articles were identified in the search, with 110 moving to full-text review, and six articles included. Two used ML to identify key biomarkers to help distinguish between allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD), three used image data to distinguish between ACD and ICD, and one used clinical and demographical data to predict the risk of positive patch tests. All studies used supervision in their ML model training with a total of 49 704 patients across all data sets. There was sparse reporting of the accuracy of these models. CONCLUSIONS: Although the available research is still limited, there is evidence to suggest that ML has potential to support diagnostic outcomes in a clinical setting. Further research on the use of ML in clinical practice is recommended.

Preservative contact allergy in occupational dermatitis: a machine learning analysis.

Occupational dermatoses impose a significant socioeconomic burden. Allergic contact dermatitis related to occupation is prevalent among healthcare workers, cleaning service personnel, individuals in the beauty industry and industrial workers. Among risk factors, the exposure to preservatives is frequent, since they are extensively added in products for occupational use. The goal of this study is to investigate the contact allergy patterns in order to understand the linkage among hypersensitivity to preservatives, occupational profiles, patients' clinical and demographic characteristics. Patch test results were collected from monosensitized patients to Formaldehyde 2%, KATHON 0.02%, thimerosal 0.1%, and MDBGN 0.5%; information was also collected for an extended MOAHLFA (Male-Occupational-Atopic-Hand-Leg-Face-Age) index. To assess the relationship between allergen group and occupational-related ACD, the chi-square test for independence was utilized. To uncover underlying relationships in the data, multiple correspondence analysis (MCA) and categorical principal components analysis (CATPCA), which are machine learning approaches, were applied. Significant relationships were found between allergen group and: occupation class, atopy, hand, leg, facial, trunk, neck, head dermatitis, clinical characteristics, ICDRG 48 h and ICDRG 72 h clinical evaluation. MCA and CATPCA findings revealed a link among allergen group, occupation class, patients' demographic and clinical characteristics, the MOAHLFA index, and the ICDRG scores. Significant relationships were identified between the allergen group and various manifestations of dermatitis. The utilization of machine learning techniques facilitated the discernment of meaningful patterns in the data.

[Translated article] Standard and Expanded Series Patch Testing Update by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC).

After the meeting held by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC) back in October 2021, changes were suggested to the Spanish Standard Series patch testing. Hydroxyethyl methacrylate (2% pet.), textile dye mixt (6.6% pet.), linalool hydroperoxide (1% pet.), and limonene hydroperoxide (0.3% pet.) were, then, added to the series that agreed upon in 2016. Ethyldiamine and phenoxyethanol were excluded. Methyldibromoglutaronitrile, the mixture of sesquiterpene lactones, and hydroxyisohexyl 3-cyclohexene (Lyral) were also added to the extended Spanish series of 2022.

[Is occupational allergic contact dermatitis within the armed forces an unrecognized problem?] / Kontaktallergiskt eksem ­ vanlig arbetsskada i försvaret?

In the armed forces, marching still remains a major component in the training of the young recruits. In the following we describe a young recruit who, following instructions, prophylactically used adhesives to prevent chafing. The recruit developed an allergic contact dermatitis with generalized spreading. The adhesive products recommended are sold on a global market and are extensively used.  Allergic contact dermatitis from these products have so far only been reported from Sweden. Unfortunately, even though the first cases were reported some years ago, new cases are still diagnosed. When medical devices are recommended to be used on the skin for a prolonged time and under extreme conditions, sensitization and a subsequent allergic contact dermatitis must be considered.