No abstract

Nickel is the most frequent cause of contact allergy worldwide and has been studied extensively. This clinical review provides an updated overview of the epidemiology, exposure sources, methods for exposure quantification, skin deposition and penetration, immunology, diagnosis, thresholds for sensitization and elicitation, clinical pictures, prevention, and treatment. The implementation of a nickel regulation in Europe led to a decrease in the prevalence of nickel allergy, and changes in the clinical picture and disease severity. Nevertheless, the prevalences of nickel allergy in the European general population are approximately 8% to 19% in adults and 8% to 10% in children and adolescents, with a strong female predominance. Well‐known consumer items such as jewellery and metal in clothing are still the main causes of nickel allergy and dermatitis, although a wide range of items for both private and occupational use may cause dermatitis. Allergic nickel dermatitis may be localized to the nickel exposure site, be more widespread, or present as hand eczema. Today, efficient methods for exposure quantification exist, and new insights regarding associated risk factors and immunological mechanisms underlying the disease have been obtained. Nevertheless, questions remain in relation to the pathogenesis, the persistent high prevalence, and the treatment of severe cases.

The objective of the present study is to describe any changes in the prevalence of sensitization to common contact allergens in patch-tested patients over a 12-year period. Attention is given to possible effects of preventive strategies introduced in Denmark regarding nickel and chromate sensitization during that period, and particular areas of concern are identified. Members of the Danish Contact Dermatitis Group collected patch-test results from consecutive eczema patients as well as information about exposures and demographic variables over a 6-month period in 1985-86. The investigation was repeated in 1997-98 in the same clinics, at the same time of year, using identical methods and patch-test substances, including nickel sulphate 5%, potassium dichromate 0.5% and fragrance mix 8%. Nickel was the most common contact allergen in both study periods, followed by the fragrance mix. In children 0-18 years of age, the frequency of nickel allergy decreased from 24.8% in the first study period to 9.2% in the second study period (P < 0. 0008). Fragrance mix allergy doubled in frequency from 4.1% in 1985-86 to 9.9% in 1997-98, an increase that affected all age groups. Contact allergy to potassium dichromate decreased significantly from 3.0% in the first period to 1.2% in the second period (P = 0. 001). The decrease was seen in both sexes and was most pronounced among those of working age. No other significant changes were found in the frequency of sensitization to common allergens over the 12-year observation period.

Objectives: To provide an updated estimate of the prevalence of contact allergy in the general population based on data from our previous review combined with new data from an updated search for relevant studies published between 2007 and 2017. Methods: Two authors independently searched PubMed for studies reporting on the prevalence of contact allergy in samples of the general population. Proportion meta-analyses were performed to calculate the pooled prevalence estimates of contact allergy. Results: A total of 28 studies were included in the analysis, covering 20 107 patch tested individuals from the general population. Overall, the pooled prevalence of contact allergy was 20.1% (95% confidence interval [CI]: 16.8%-23.7%). In children and adolescents (<18 years), the prevalence was 16.5% (95%CI: 13.6%-19.7%). The prevalence was significantly higher in women (27.9% [95%CI: 21.7%-34.5%]) than in men (13.2% [95%CI: 9.3%-17.6%]). The most common allergen was nickel (11.4% [95%CI: 9.4%-13.5%]), followed by fragrance mix I (3.5% [95%CI: 2.1%-5.4%]), cobalt (2.7% [95%CI: 2.1%-3.4%]), Myroxylon pereirae (1.8% [95%CI: 1.0%-2.7%]), chromium (1.8% [95%CI: 1.3%-2.6%]), p-phenylenediamine (1.5% [95%CI: 1.0%-2.1%]), methylchloroisothiazolinone/methylisothiazolinone (1.5% [95%CI: 0.8%-2.5%]), and colophonium (1.3% [95%CI: 1.0%-1.6%]).Conclusions: This meta-analysis confirmed that at least 20% of the general population are contact-allergic to common environmental allergens. It highlights the need for more effective preventive strategies for common allergens in consumer goods, cosmetics, and the workplace.contact allergy, epidemiology, general population, hapten, meta-analysis, prevalence and Janssen Pharmaceuticals. J. P. Thyssen is supported by an unrestricted grant from the Lundbeck Foundation. ORCID Farzad Alinaghi

Accurate assessments of the burden of hand eczema (HE) in the general population are important for public awareness and intervention. The aim of this systematic review and meta-analysis was to provide updated estimates of prevalence and incidence, alongside additional epidemiological endpoints on HE in the general population.PubMed, Embase and Web of Science were searched for studies reporting the prevalence and/or incidence of HE in the general population. Proportion meta-analyses were performed to calculate pooled estimates of prevalence, incidence, severity, and the proportion of individuals with HE and a history of atopic dermatitis. Sixty-six studies were included in the quantitative analysis encompassing 568 100 individuals. The pooled estimates for lifetime, 1-year, and point prevalence were 14.5% (95% confidence interval [CI]: 12.6-16.5), 9.1% (95% CI: 8.4-9.8) and 4.0% (95% CI: 2.6-5.7), respectively. The pooled incidence rate of HE was 7.3 cases/1000 person-years (95% CI: 5.4-9.5). The occurrence of HE was 1.5-2 times higher in females than males. More than one third suffered from moderate/severe disease and around one third had a history of atopic dermatitis. HE was a recurrent, long-lasting disease with an average age at onset of the early-to mid-twenties. In conclusion; HE is a highly prevalent disease in the general population and carries a significant risk of long-term or chronic disease.

Background Clinical surveillance of the prevalence of contact allergy in consecutively patch tested patients is a proven instrument to continually assess the importance of contact allergens (haptens) assembled in a baseline series. Objectives To present current results from the European Surveillance System on Contact Allergies, including 13 countries represented by 1 to 11 departments. Methods Anonymized or pseudonymized patch test and clinical data from various data capture systems used locally or nationally as transferred to the Erlangen data centre were pooled and descriptively analysed after quality control. Results In the 4 years (2015‐2018), data from 51 914 patients patch tested with the European baseline series (EBS) of contact allergens were analysed. Contact allergy to nickel was most frequent (17.6% positive), followed by contact allergy to fragrance mix I (6.9%), methylisothiazolinone (MI; 6.2%), and Myroxylon pereirae resin (balsam of Peru; 5.8%). Conclusions While the prevalence of MI contact allergy decreased substantially following regulatory intervention, the persistently high levels of allergy to metals, fragrances, other preservatives, and rubber chemicals point to problems needing further research and, potentially, preventive efforts. Results with national additions to the baseline series provide important information on substances possibly to be considered for inclusion in the EBS.

Background: Polyethylene glycols (PEGs) are polymers of varying molecular weight (MW) used widely as excipients in drugs and other products, including the mRNA vaccines against coronavirus disease 2019. Allergy to PEGs is rare. Skin testing and graded challenge carries a high risk of inducing systemic reactions. Objective: We evaluated skin prick test (SPT) results and in vitro reactivity over time to different MW PEGs and assessed cross-sensitization patterns in PEG allergy. Methods: Ten patients with previously diagnosed PEG allergy underwent SPT twice with PEGs 26 months apart. Lower MW (PEG 300, 3000, 6000) were tested, followed by PEG 20,000, in stepwise, increasing concentrations. Cross-sensitization to polysorbate 80 and poloxamer 407 was assessed. SPT was performed in 16 healthy controls. In vitro basophil histamine release (HR) test and passive sensitization HR test were performed in patients and controls. Results: Patients previously testing positive on SPT to PEG 3000 and/or 6000 also tested positive to PEG 20,000. Patients with a longer interval since diagnosis tested negative to lower MW PEGs and positive mainly to higher concentrations of PEG 20,000. Three patients developed systemic urticaria during SPT. Eight patients showed cross-sensitization to poloxamer 407 and 3 to polysorbate 80. All controls tested negative. In vitro tests showed limited usefulness. Conclusions: Skin test reactivity to PEG can decrease over time, but titrated SPT with increasing concentrations of PEG 20,000 can be diagnostic when lower MW PEGs test negative. To avoid systemic reactions, stepwise SPT is mandatory. (J Allergy Clin Immunol 2021;nnn:nnn-nnn.)

Background Polyethylene glycols (PEGs) are widely used as excipients in drugs, cosmetics and household products. Immediate‐type allergy to PEGs including anaphylaxis is rare. The recent introduction of the mRNA‐based COVID‐19 vaccines has led to an increased focus on PEG as a possible culprit of allergic reactions to the vaccines. A low awareness of the allergenic potential of PEG among consumers, manufacturers and doctors leads to under‐diagnosis and under‐reporting of allergy to PEGs, putting patients at risk of repeated severe reactions. Objectives To investigate clinical manifestations, time to diagnosis and impact of a PEG allergy diagnosis on the daily life of patients diagnosed with allergy to PEG from 2010 to 2019. Method Ten patients diagnosed with allergy to PEG were included. Detailed clinical history was obtained, and allergy investigations had been performed at the time of diagnosis. All patients were contacted and asked to retrospectively complete a questionnaire about causes and impact on daily life of an allergy to PEG, scored on a likert scale (0–10) before and after diagnosis. Results Eight patients had experienced at least one anaphylactic reaction requiring adrenaline treatment. Anaphylaxis was primarily caused by antibiotic/analgesic tablets, depot‐steroids, antacids and laxatives. Seven patients reported repeated reactions before diagnosis (median 3, range 2–6). Median time from first reaction to diagnosis was 20 months (range 2–120). None of the patients experienced severe allergic reactions after the diagnosis. Median likert score of the impact on daily life before diagnosis was 7 compared with 4 after diagnosis. Conclusion and clinical relevance The clinical manifestations of PEG allergy are often dramatic. Improved awareness about the clinical presentation and common culprits, clear product labelling and a standardized nomenclature is needed to ensure the timely diagnosis of PEG allergy to prevent repeated anaphylactic reactions with severe impact on patients’ lives.