This is the second part of a two-part narrative review of contact allergy and allergic contact dermatitis to alkyl glucosides (AGs), presenting patient demographics, products causing allergic contact dermatitis, patch test considerations, co-/cross-reactions, and the presence of AGs in cosmetics and other products. There are strong indications that atopic patients, or at least those with a history of atopic dermatitis, have an increased risk of becoming sensitized to AGs. This results in higher prevalences of sensitization to AGs in pediatric populations. Female sex does not appear to be a risk factor. The sites most commonly affected by allergic contact dermatitis are the face (+/- neck and scalp), hands, and "generalized." Occupational allergic contact dermatitis from AGs does not occur frequently and usually manifests as hand dermatitis from shampoos (in hairdressers) and hand cleansers. Cosmetics are by far (>80%) the most common products responsible for allergic reactions to AGs. Other culprit products include household and industrial cleansers, topical medications, wound foam dressings, and antiseptic products. Patch testing with commercial decyl glucoside (5% pet.) and lauryl glucoside (3% pet.) results not infrequently in dubious (?+) and irritant reactions. There are concerns that some weak "allergic" reactions may actually be false-positive. Frequent coreactivity between AGs may be caused by cross-reactions, concomitant sensitization due to mixed alkyl chain compositions, common allergenic impurities, and overlapping composition of patch test materials. Cosmetics with the highest prevalences of one or more AGs are cleansing products for babies and children.
BACKGROUND:Surfactants in personal care products are an established trigger of allergic contact dermatitis. However, regional data comparing market usage with sensitization rates remain limited. OBJECTIVES:To examine 15-year trends in Thai surfactant prevalence and correlate them with clinical patch test reactivity. METHODS:Surfactant prevalence in 6864 personal care products was surveyed using the Thai Contact Allergen Avoidance Program database (2010-2024). Concurrently, patch test results from 6603 patients were analyzed across 3 5-year intervals. RESULTS:Cocamidopropyl betaine (CAPB) was the most prevalent surfactant overall (20.3%) and in cleansers (43.2%), whereas polysorbates predominated in non-cleansing formulations (17.9%). In cleansers, use of CAPB (P < 0.001), glucosides (P = 0.009), and cetrimonium chloride (P < 0.001) rose over time. Cetrimonium bromide, benzalkonium chloride, and CAPB showed the highest patch test positivity rates. Conversely, positivity declined for CAPB (P < 0.001), benzalkonium chloride (P = 0.007), lauryl glucoside (P = 0.019), and cocamide diethanolamine (P < 0.001). CONCLUSIONS:The Thai market is shifting toward milder surfactants. A paradoxical decline in CAPB and lauryl glucoside sensitization occurred despite their rising prevalence. Continuous market monitoring is essential to keep patch test series and patient counseling relevant.
INTRODUCTION:This study assessed disease control and symptom burden among US adults with moderate-to-severe atopic dermatitis (AD) treated with topical-only or systemics (conventional [corticosteroids/immunosuppressants]/advanced [biologics/JAKi]) ± topicals. METHODS:Data were obtained from the Adelphi Atopic Dermatitis Disease Specific Programme, a cross-sectional real-world survey (August 2022-March 2023). Physicians completed patient record forms, and patients completed quality-of-life and symptom questionnaires. Uncontrolled AD was defined by physician-reported flares, dissatisfaction with control, and/or deteriorating disease. Patient-reported outcomes included the Dermatology Life Quality Index (DLQI), Patient-Oriented Eczema Measure (POEM), and Work Productivity and Activity Impairment (WPAI-AD). RESULTS:Among 619 analyzed patients (mean age 40.5, 50% female), 30.2% had uncontrolled AD-36.4% treated with topicals-only and 63.6% with systemics ± topicals. Patients with uncontrolled AD on systemics reported higher symptom burden (DLQI 10.0, POEM 11.8) and activity impairment (WPAI 30.9) versus topicals-only (DLQI 3.3, POEM 8.7, WPAI 13.9). Absenteeism was notable in systemic-treated patients (12.1) but absent in topical-only groups. Patients with controlled AD showed lower symptom scores and better quality of life (QoL) across all treatments. Conventional systemics were associated with greater burden than advanced systemics. CONCLUSION:Despite available treatments, a substantial proportion of patients with moderate-to-severe AD remain uncontrolled, experiencing significant symptom burden and impaired QoL-underscoring the need for improved therapeutic strategies.
BACKGROUND:Treatment discontinuation is common with Janus kinase inhibitors, such as upadacitinib, in moderate-to-severe atopic dermatitis (AD), and this often results in disease relapse and an increased patient burden. OBJECTIVE:To explore reasons for discontinuation, risk factors, and willingness to reuse upadacitinib. METHODS:This retrospective study enrolled 104 patients with AD (50 in the discontinuation, 54 in the non-discontinuation) from Xiangya Third Hospital (Feb-Mar 2026). Data on DLQI, pruritus NRS, and SD-NRS were collected. Recurrence was defined as a ≥25% increase in pruritus after discontinuation. χ2 tests, Fisher's exact test, t tests, and logistic regression were used. RESULTS:Upadacitinib significantly relieved pruritus and improved sleep in both groups. The main reason for discontinuation was satisfactory efficacy, whereas unsatisfactory efficacy was associated with multiple concomitant factors. Shorter diagnosis duration was associated with satisfaction-driven withdrawal, while no such correlation was found among medication continuers. The overall relapse rate was 36.0%. Male sex and smoking were independent relapse risk factors. Among relapsed patients, only 27.8% were willing to resume upadacitinib (61.1% refused). Those who previously discontinued treatment for unfavorable reasons tended to decline retreatment for identical causes. CONCLUSIONS:Upadacitinib is effective for early AD. Close monitoring, targeted education, financial support, and optimized care can improve adherence and reuse willingness.
BACKGROUND:Isothiazolinones are responsible for an epidemic of allergic contact dermatitis across Europe over the past 2 decades. Regulatory restrictions on methylisothiazolinone (MI) in cosmetics have been followed by declining sensitization rates in surveillance networks. Benzisothiazolinone (BIT) and octylisothiazolinone (OIT) have emerged as sensitizers of growing clinical relevance. OBJECTIVE:To characterize temporal trends in sensitization to MCI/MI, MI, BIT, and OIT over more than 2 decades at a single center in Gran Canaria, Spain. METHODS:Cross-sectional study of patients patch-tested between 2003 and 2025. Temporal trends were analyzed using univariate analysis and generalized additive logistic regression models adjusted for age, sex, atopic dermatitis, and occupation. RESULTS:Sensitization rates were 11.1% for MCI/MI, 11.6% for MI, 7.6% for BIT, and 0.9% for OIT. MCI/MI and MI sensitization peaked around 2014-2015 and 2020-2021, respectively, then declined following European cosmetic regulatory restrictions. BIT sensitization showed a flatter, sustained trend and was independently associated with older age, male sex, and absence of atopic dermatitis. CONCLUSIONS:There has been a decline in MCI/MI and MI sensitization after regulatory restrictions on cosmetic application. BIT is an emerging isothiazolinone of concern with a distinct occupational profile, warranting regulatory attention to household cleaners and industrial sources.
BACKGROUND:Various diseases are induced by allergic reactions to metals, among which nickel, cobalt, and chromium are representative examples. OBJECTIVE:To investigate sensitization to these metals in Japan from April 1990 to March 2025. METHODS:A total of 1985 patients were patch tested with nickel sulfate, cobalt chloride, and potassium dichromate. Reactions ranging between + and +++ by the International Contact Dermatitis Research Group scoring system at day 3 or 7 were regarded as positive. RESULTS:Positive rates to nickel, cobalt, and chromium were 26.1%, 9.0%, and 4.9%, respectively. Significantly more women positively reacted to nickel than men, and there was an overt tendency toward a higher rate in the younger age group. 62.1% of cobalt-positives also reacted positively to nickel, and the positive rate to chromium decreased throughout 35 years. CONCLUSION:Accessories such as ear piercing (wounded skin) continue to play an essential role in nickel sensitization among young women. The high positive rate of nickel and cobalt co-sensitization suggests a potential synergy in immune activation. On the contrary, the decrease in chromium sensitization correlates with decreased use of cement and reduced exposure sources, such as decreased use in leather tanning. The challenge facing both Japan and the US is to reduce nickel sensitization following the successful European Union's regulations model.
BACKGROUND:Propolis, Myroxylon pereirae resin (balsam of Peru), and colophonium are complex botanical materials that frequently co-react when patch tested. Detailed knowledge of their compositions may help explain the co-reactivity pattern and identify the haptens responsible for positive patch tests. OBJECTIVE:To study the compositions of propolis, M. pereirae resin, and colophonium used for patch testing and assess whether they contain identical ingredients. METHODS:The ingredients of 3 samples of propolis, 2 of M. pereirae resin and 2 of colophonium used for preparing patch test preparations by Chemotechnique and SmartPractice (brand Allergeaze) were analyzed using gas chromatography-mass spectrometry. RESULTS:Major ingredients in Brazilian propolis were non-volatile fatty materials; in Chinese propolis tectochrysin, pinostrobin, pinocembrin, and p-vinylguaiacol; in M. pereirae resin benzyl benzoate, benzyl cinnamate and nerolidol; in colophonium Chemotechnique isoabienol, β-caryophyllene, sandaracopimarinal, sandaracopimarinol and longifolene; in colophonium Allergeaze lupeol acetate, longifolene, sandaracopimarinol, abietinal and isoabienol. Only 11 chemicals were present in 2 materials, none in all 3. CONCLUSIONS:Very few identical chemicals were found in propolis, M. pereirae resin, and colophonium. The results do not support the notion that the frequently observed co-reactivity to these complex natural materials can be explained by identical chemicals detected in this study.
The understanding of atopic dermatitis (AD) pathogenesis is evolving beyond the barrier-immune dichotomy, with neuropsychological factors gaining prominence as a central component. This review systematically decodes the multi-level crosslink within the "brain-skin axis" in AD, encompassing recent advances in peripheral sensory neuron sensitization, central neural remodeling, and neuro-immune interactions. We elaborate on the roles of neuropeptides, cytokines, the autonomic nervous system, and the hypothalamic-pituitary-adrenal axis in the itch-scratch cycle, inflammation amplification, and mood disorders. Furthermore, we examine the influence of novel therapeutic strategies, including biologics, Janus kinase inhibitors, psychological approaches, and microbiome modulation, on these neuropsychological components. Finally, we outline future research directions, such as elucidating the molecular mechanisms of neuro-immune crosstalk, identifying relevant biomarkers, and establishing interdisciplinary diagnostic and treatment models. A deeper understanding of the role of neuropsychological factors in AD not only drives innovation in treatment strategies but also offers new perspectives for breaking the vicious cycle of "pruritus-inflammation-psychological distress."
INTRODUCTION:Lauryldimethylamine oxide (LDAO), or lauramine oxide, is an amine-oxide-based surfactant to which allergic contact dermatitis (ACD) has been reported. We present our experience of routinely patch testing LDAO between 2024 and 2026, characterizing positivity rate, clinical relevance, and concomitant reactions with the cocamidopropyl betaine (CAPB) family. METHODS:Seven hundred sixty-six patients were tested to LDAO at our tertiary referral center. Data collection included reaction strength, clinical relevance, primary site of dermatitis, exposure sources, and concomitant reactions. RESULTS:Twenty-nine patients (3.79%) reacted to LDAO at their final reading, and LDAO had definite or probable clinical relevance in 8 of these patients (27.6%). Primary sites of dermatitis included the face (4), hands (2), eyelids (1), and scalp (1). LDAO was declared in dishwashing soaps (6) and hand soaps (2) in clinically relevant cases. Cross-reactivity between LDAO and the CAPB family was clinically and statistically significant. CONCLUSION:Our results suggest clinical cross-reactivity between amine oxides and the CAPB family. LDAO-allergic patients should avoid amine oxides and CAPB-related compounds. We recommend LDAO be more routinely tested, as it may help identify amine oxide- or CAPB-related ACD that would otherwise be missed.
