The Effect of Atopy in the Prevalence of Contact Sensitization: The Experience of a Greek Referral Center

Prevalence of Contact Allergy to Neomycin in Dermatitis Patients: A Systematic Review and Meta-Analysis

Neomycin, an aminoglycoside antibiotic frequently employed in topical formulations, is a recognised allergen that is part of many baseline series and can cause contact allergy (CA) in both adults and children. It is an allergen of interest as it has a widespread use in over-the-counter and prescription products globally, but geographical variations may exist. This study aimed to establish prevalence estimates of CA to neomycin in dermatitis patients and to investigate potential geographical variations. Three databases (PubMed, Embase, and Web of Science) were screened, revealing 70 included studies comprising 456 372 adults and 17 720 children who underwent patch testing. The pooled prevalence of CA to neomycin was found to be 3.2% (95% confidence interval [CI]: 2.6%-3.8%) in adults and 4.3% (95% CI: 2.65%-6.3%) in children. The highest prevalences were observed in North America (adults: 6.4%; children: 8.1%) and South Asia (adults: 4.9%), while Europe showed lower rates (adults: 2.5%; children: 0.8%). Studies after the year 2000 indicated a prevalence of 2.1% in adults and 5.1% in children across geographical regions. These findings highlight a public health concern, particularly in regions with high prevalence rates. The study underscores the need for more restrictive use of neomycin to reduce the incidence of neomycin-induced CA.

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.

Patch Testing in Patients With Severe Atopic Dermatitis Treated With Dupilumab: A Multicentric Approach in Spain

Background: Persistent localized dermatitis (PLD) or eczema flare-ups (EF) may occur in atopic dermatitis (AD) patients treated with dupilumab. They may reflect concomitant allergic contact dermatitis (ACD) exposed by the inhibition of the Th2 pathway by dupilumab in some cases. Objective: To evaluate the prevalence and etiology of these events and the impact of dupilumab on patch test outcome. Methods: We performed patch tests on 54 AD patients treated with dupilumab and evaluated the prevalence and final diagnosis of EF and PLD as well as the patch test results. Results: The patch test results were positive in 20/54 (37.0%). 21/54 patients (38.9%) had PLD and 12/54 (22.2%) had EF. Ten of 54 (18.5%) had both conditions and 11/54 (20.4%) had neither PLD nor EF. 64.5% of PLD involved the face. 83.9% patients with PLD and 90.9% patients with EF were diagnosed with inadequately controlled AD. 9.7% patients with PLD and 4.5% patients with EF were finally diagnosed with ACD. Nine of 21 (42.9%) patients patch tested twice were positive either before and/or during dupilumab. Patch tests results changed over time in all of them. Conclusions: Patch testing assisted us to exclude ACD as the cause of PLD/EF in AD patients treated with dupilumab. Most PLD and EF were, however, diagnosed as poorly controlled AD. Dupilumab appeared to impact the patch test outcomes.

[Translated article] Haptens, Proteins, and Atopic Dermatitis

Atopic dermatitis is a chronic inflammatory disease that is multifactorial in nature. Allergic contact dermatitis and protein contact dermatitis are allergic conditions that may occur in the context of atopic dermatitis and be the cause of exacerbations. Although the prevalence of allergic contact dermatitis is similar in atopic patients and the general population, these 2 conditions are frequently associated because atopic inflammation disrupts the skin barrier. Skin tests are therefore recommended in atopic individuals. Dupilumab could be useful for treating allergic contact dermatitis if it is mediated by type 2 helper T cells but could exacerbate inflammation if mediated by TH1 cells: further study is needed before conclusions can be drawn. Although the mechanism by which exposure to environmental proteins exacerbates atopic dermatitis remains under discussion, such exacerbations are routinely seen in clinical practice. Prick testing is recommended in symptomatic atopic dermatitis. When prick-test findings are positive, patients should be advised to avoid the culprit substances.

A Retrospective Analysis to Investigate Contact Sensitization in Greek Population Using Classic and Machine Learning Techniques

Allergic contact dermatitis (ACD) is an inflammatory reaction affecting all age groups and both sexes. ACD is characterized by a delayed-type hypersensitivity reaction IV caused by skin contact with haptens. Chronic exposure typically leads to a decrease in erythema accompanied by lichenification (thickening and hardening of the skin) and persistent itching. The current study aims to investigate the patterns of contact sensitization in the Greek population using patch test data analysis. Patch test data from 240 patients (120 Males/120 Females) with allergic contact dermatitis were collected at the Laboratory for Patch Testing, National Reference Center for Occupational Dermatoses "Andreas Syggros" Hospital in Athens Greece. The contact allergic reactions were caused by ethylenediamine dihydrochloride 1%, thimerosal 0.5%, and methyldibromo-glutaronitrile 0.1% from the European baseline series of allergens; information was also collected for ICDRG evaluation, an extended MOAHLFA index and patient-reported outcomes (daily routine questionnaire). The chi-square test for independence and Spearman's rank were used to evaluate the association and correlation, respectively, between patient characteristics and ACD-related factors. Multiple correspondence analysis (MCA), which is a data analysis approach, was used to find and depict underlying structures in the data collection for nominal categorical data. Statistically significant associations were found between the following pairs of characteristics: eczema triggers and gender and eczema triggers and hand dermatitis. The results from MCA showed that there is correlation between allergic contact dermatitis onset, allergens, and demographic variables.

Haptens, Proteins, and Atopic Dermatitis

Atopic dermatitis is a chronic inflammatory disease that is multifactorial in nature. Allergic contact dermatitis and protein contact dermatitis are allergic conditions that may occur in the context of atopic dermatitis and be the cause of exacerbations. Although the prevalence of allergic contact dermatitis is similar in atopic patients and the general population, these 2 conditions are frequently associated because atopic inflammation disrupts the skin barrier. Skin tests are therefore recommended in atopic individuals. Dupilumab could be useful for treating allergic contact dermatitis if it is mediated by type 2 helper T cells but could exacerbate inflammation if mediated by T_H1 cells: further study is needed before conclusions can be drawn. Although the mechanism by which exposure to environmental proteins exacerbates atopic dermatitis remains under discussion, such exacerbations are routinely seen in clinical practice. Prick testing is recommended in symptomatic atopic dermatitis. When prick-test findings are positive, patients should be advised to avoid the culprit substances.

Analysis of Prevalence and Risk Factors of Contact Sensitization with respect to the Occupational Profiles in a Greek Patient Cohort: A Retrospective Analysis of a Greek Referral Centre and Future Perspectives

Contact dermatitis is a frequent skin disorder related to environmental and occupational etiological factors, which could potentially affect all age groups, as well as both genders. The current study is aimed at exploring the patterns of contact sensitization with respect to the population's occupational patterns in Greece. A retrospective analysis was performed in a cohort of 1978 patients from 2014 to 2016. Patients were divided into two categories; blue collars (BlC) and white collars (WhC), as well as detailed occupation was considered. Separation was performed on the basis of their profession, i.e., labor workers and handicraftsmen were sorted to the BlC group, while office employees were sorted to the WhC group. The common allergen in all occupational subgroups was nickel sulphate. The three most prevalent allergens in both BlC and WhC were nickel sulphate 5%, fragrance mix (I) 8%, and Balsam of Peru 25%. WhC males were uniquely sensitized to colophony 20% and formaldehyde 2%, and WhC females were uniquely sensitized to 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT) and neomycin sulphate 20%. Sensitization to allergens manifested occupation-specific patterns. Allergic contact dermatitis surveillance is of great importance towards the clinical and systematic understanding of the disease, especially with respect to the patient's occupational profile.