Current frequency of contact allergy to isothiazolinones (methyl-, benz- and octylisothiazolinone) across Europe.

BACKGROUND: The use of methylisothiazolinone (MI) as a preservative in cosmetic products caused an alarming increase in MI contact allergy across Europe in the 2010s. This was followed by regulations of use with a total ban on leave-on (implemented in 2017) and reduced use concentrations in rinse-off cosmetics (2018). OBJECTIVE: To follow-up on the prevalence of contact allergy to MI and the related benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in consecutively patch-tested patients in Europe. METHODS: A cross-sectional audit following the design of two previous audits on MI contact allergy from 1 May 2022 to 31 October 2022 included all patients patch tested with the European baseline series, including or supplemented with MI, BIT and OIT across 10 departments in eight European countries. RESULTS: A total of 2554 patients were consecutively patch tested with the three isothiazolinones during the study period. The prevalence of MI and BIT contact allergy was 2.9% (95% confidence interval [CI]: 2.3%-3.7%; range 1.1%-5.8%) and 3.1% (95% CI: 2.4%-3.9%; range 0.0%-6.6%), respectively; that of OIT was 0.7% (95% CI: 0.4%-1.1%; range 0%-3.2%). Rinse-off cosmetic (73.3%) and leave-on cosmetic products (13.3%) were still associated with eliciting allergic contact dermatitis to MI. CONCLUSION: We confirmed a positive impact of regulatory measures on the prevalence of MI contact allergy in Europe, which halved compared to 2015. However, our data suggest that consumers may still be exposed to older cosmetic products containing MI. BIT has superseded MI in causing contact allergy, despite not being allowed for use in cosmetic products.

Contact allergy to neomycin in consecutively patch tested Danish eczema patients from 2000 to 2023: A cross-sectional study.

BACKGROUND: Neomycin is an aminoglycoside antibiotic that may cause contact allergy. It was withdrawn as a medicine for human use in Denmark in October 2009 but is still found in some vaccines. OBJECTIVES: To identify time trends in contact allergy to neomycin in the period from 2000 to 2023. METHODS: A cross-section study of patients ≥18 years consecutively patch-tested with neomycin sulfate (20% in pet.) at Gentofte Hospital, Denmark, during the period 2000-2023 was conducted. RESULTS: The overall prevalence of contact allergy to neomycin was 1.4%. The prevalence was significantly lower in the period '2010-2023' (1.2%) than in '2000-2009' (1.8%) (p < 0.005). Contact allergy to neomycin was significantly positively associated with facial dermatitis and age >40 years, and significantly negatively associated with occupational dermatitis and hand dermatitis. No changes in sex, occupational dermatitis, atopic dermatitis, hand dermatitis, leg dermatitis, facial dermatitis, or age > 40/≤40 (the MOAHLFA-index) were identified when comparing neomycin contact allergic-patients in the two periods '2010-2023' and '2001-2009'. CONCLUSION: Neomycin is a rare cause of contact allergy in Denmark with a significantly lower prevalence following its withdrawal as a medicinal product for human use in Denmark in 2009.

Evaluation of Delayed Contact Hypersensitivity in Patients with Rosacea.

Introduction: Rosacea is a common chronic inflammatory dermatosis characterized by erythema, telangiectasia, papules, and pustules on the central face. The frequency of contact sensitization complicating rosacea and its therapy is unknown, with only few studies published in the literature. In the present study, we aimed to evaluate contact sensitivity in patients with rosacea. Methods: A total of 50 rosacea patients and 50 age- and sex-matched healthy controls were enrolled. Both groups were patch tested with the European Baseline Series. Results: A positive reaction to at least one allergen of the European Baseline Series was observed in 15 (30%) of rosacea patients and 10 (20%) of the healthy controls. Although the rate of positive reaction in the rosacea group was higher than in the controls, no statistically significant difference was documented. In addition, the total number of positive reactions to allergens in the rosacea group was higher than the control group, namely, 26 versus 17. Conclusion: Contact hypersensitivity may coexist with rosacea. Its identification holds significant clinical relevance, influencing the long-term management and justifying the application of patch testing in rosacea patients.

The correlation between self-reported hand eczema and clinically based diagnosis in professional cleaners.

BACKGROUND: Most studies investigating the prevalence of hand eczema (HE) in professional cleaners use self-reported questionnaire-based data. However, no validation studies of self-reporting of HE among professional cleaners have previously been conducted. OBJECTIVES: To investigate (1) the point prevalence of self-reported HE, (2) the point prevalence of HE estimated by physical examination of the hands and (3) the sensitivity and specificity of self-reporting of HE compared with the diagnosis based on physical examination among professional cleaners. METHODS: Professional cleaners at three different hospitals in Region Zealand were invited to fill out a questionnaire. The point prevalence of self-reported HE was estimated based on questions from the Nordic Occupational Skin Questionnaire. After completing the questionnaire, each cleaner underwent a physical examination of the hands by a dermatologist on the same day. RESULTS: In total, 234 cleaners were invited to participate in the study, and 224 (response rate = 96.0%) agreed to take part. Based on the self-reported questionnaires, 5.3% (n = 12) of the cleaners had current HE. Based on an examination by a physician, 19.2% (n = 43) of the cleaners had current HE. The sensitivity of self-reported HE was found to be 28.0%, while the specificity was found to be 100.0%. The positive predictive value was found to be 100.0%, while the negative predictive value was 85.0%. CONCLUSION: The true point prevalence of HE among professional cleaners is underestimated when based on self-reporting.

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.

Ecotoxicity, Health Risks and Contact Allergy Due to p-Phenylenediamine in Hair Dyes and Tattoos: Female Students' Perspectives.

While the financial advantages of hair coloring and tattooing are widely acknowledged, environmental hazards and health risks linked to this trend due to their p-phenylenediamine (PPD) content have received less attention. Health education on hair-dying products is warranted to enhance the public's awareness of hair-dying ingredients and their side effects.  A cross-sectional study was therefore conducted with 319 students to assess knowledge of ecotoxicity, health risks, and practices of hair dyeing and tattooing among undergraduate students. A random sample of 59 students was checked for any allergic morphology in the scalp and exposed areas of skin near the neck, ears, palms, and nails. Responses collected were used for data analyses using IBM SPSS Statistics for Windows, Version 17 (Released 2008; IBM Corp., Armonk, New York, United States). Use of hair dye was significantly high among study participants 58.5% (n=187; p<0.05). However, their knowledge regarding the presence of PPD in hair dyes and associated environmental toxicity (37.8%, n=121) was very limited. The majority of participants did not do any allergy tests before applying hair dye (88.9%, n=283). The study revealed that the main reason for hair coloring was as a fashion statement (93.7%, n=299). Regarding tattooing practices, 96.9% (n=309) of study participants had never practiced tattoos, and hence, the prevalence of tattooing was 3.9% (n=12). These data confirmed that the practice of hair dyeing as a style statement was high among students. However, the majority were unaware of their PPD contents and their potential ecotoxicity and health risks.

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.

Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) after administration of corticosteroids: Case series and review of literature.

BACKGROUND: Cutaneous manifestations of drug-induced type IV reactions vary widely, with symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) being a less common presentation. Corticosteroids (CS), primarily known for their anti-inflammatory effects, rarely induce hypersensitivity reactions. OBJECTIVE: The aim of this case series is to report four cases of SDRIFE following systemic prednisolone therapy and to review existing CS classification proposals to better understand cross-reactivity of CS. PATIENTS/METHODS: Patients recruited at a German dermatology centre underwent allergologic evaluation including prick and patch testing with various CS. Positive cases underwent oral challenge testing with alternative agents. The classification systems of Coopman et al. and Baeck et al. were taken into account. DISCUSSION: Despite a paucity of literature, CS-induced type IV reactions do occur, including SDRIFE. Classification systems based on chemical structure provide insight into cross-reactivity patterns. Provocation tests with alternative CS highlight the complexity of managing CS hypersensitivity. CONCLUSION: SDRIFE may develop following systemic prednisolone therapy. Classification systems are helpful in understanding cross-reactivity and help in the selection of alternative preparations but are not always reliable. Individualised assessment is crucial for managing CS hypersensitivity, with consideration of alternative agents and emergency use of CS when necessary.

Sunscreens Part 2: Regulation and Safety.

The second part of this CME article discusses sunscreen regulation and safety considerations for humans and the environment. First, we provide an overview of the history of the United States Food and Drug Administration's regulation of sunscreen. Recent Food and Drug Administration studies clearly demonstrate that organic ultraviolet filters are systemically absorbed during routine sunscreen use, but to date there is no evidence of associated negative health effects. We also review the current evidence of sunscreen's association with vitamin D levels and frontal fibrosing alopecia, and recent concerns regarding benzene contamination. Finally, we review the possible environmental effects of ultraviolet filters, particularly coral bleaching. While climate change has been shown to be the primary driver of coral bleaching, laboratory-based studies suggest that organic ultraviolet filters represent an additional contributing factor, which led several localities to ban certain organic filters.

Contact allergy to topical ophthalmic medications: A retrospective single-centre study of three decades.

BACKGROUND: The prevalence of contact allergy to various ophthalmic medications appears to be rare; however, data on culprits, clinical relevance of sensitizations, and changes in frequency within recent decades are limited. OBJECTIVE: This study aimed to investigate the clinical relevance, risk factors, and prevalence of contact allergy to topical ophthalmic medications in patients suspected of allergic contact dermatitis to ophthalmic medication. METHODS: We retrospectively analysed patch test results and clinical data for 754 patients patch-tested with an ophthalmic medication series at our tertiary referral centre between January 1992 and December 2022. RESULTS: In total, 37.5% (283/754) of patch-tested patients had a contact allergy to at least one ophthalmic allergen, with 87.3% (247) being clinically relevant sensitization. Phenylephrine (31.8%, 192/604), povidone-iodine (29%, 27/93), and tobramycin (23%, 46/200) were the most important sensitizers. The incidence of contact allergies increased significantly in a linear manner (p = 0.008) from 20% to 44.1% within the study period. Male sex and age above 40 were risk factors for contact allergy to ophthalmic medication. CONCLUSIONS: One third of patch tested patients had allergic contact dermatitis to ophthalmic medication, particularly phenylephrine. Male sex and age above 40 years were independent risk factors and drove the linear increase in contact allergy to ophthalmic medications within the past 31 years.

Hand eczema symptoms, exposures and skin care in orthodontics : A national, cross-sectional questionnaire-based survey.

OBJECTIVES: Occupational hand eczema is a common inflammatory skin condition among healthcare professionals. Orthodontists are frequently exposed to a variety of irritating and allergenic substances, and therefore they belong to a predisposed group to develop hand eczema. However, current data on the prevalence and predisposing factors among orthodontists to provide adequate prophylaxis are lacking. METHODS: An anonymous online survey was conducted in Germany between January and February 2023 and distributed to 2402 orthodontists. The questionnaire addressed general information on current skin status, as well as occupational skin exposure and skin care. RESULTS: A total of 209 orthodontists responded to the survey. Seventy-four percent reported experiencing hand eczema-specific symptoms within the last 12 months, with 24% describing moderate and 10% describing severe symptoms. The average daily glove wearing time was stated to be 6 ± 2 h. The most frequently reported triggers at work were frequent hand washing (62.7%) and hand disinfection (59.1%). Among all the respondents, 22.6% stated not using either barrier cream or moisturizer. CONCLUSIONS: This study showed a high prevalence of hand eczema symptoms among orthodontists, which is probably due to frequent disinfection, hand washing, and contact with allergens such as acrylates. In this professional group especially, against a background of future increasing acrylate and epoxy resin exposures due to in-office three-dimensional printing processes, timely education and skin protection could decisively counteract the pathogenesis of hand eczema.