Allergic contact dermatitis in children

Intermittent Fasting Modulates Immune Response by Generating Tregs via TGF-β Dependent Mechanisms in Obese Mice with Allergic Contact Dermatitis

People with obesity maintain low levels of inflammation; therefore, their exposure to foreign antigens can trigger an excessive immune response. In people with obesity or allergic contact dermatitis (ACD), symptoms are exacerbated by a reduction in the number of regulatory T cells (Tregs) and IL-10/TGF-β-modified macrophages (M2 macrophages) at the inflammatory site. Benefits of intermittent fasting (IF) have been demonstrated for many diseases; however, the immune responses regulated by macrophages and CD4+T cells in obese ACD animal models are poorly understood. Therefore, we investigated whether IF suppresses inflammatory responses and upregulates the generation of Tregs and M2 macrophages in experimental ACD animal models of obese mice. The IF regimen relieved various ACD symptoms in inflamed and adipose tissues. We showed that the IF regimen upregulates Treg generation in a TGF-β-dependent manner and induces CD4+T cell hypo-responsiveness. IF-M2 macrophages, which strongly express TGF-β and inhibit CD4+T cell proliferation, directly regulated Treg differentiation from CD4+T cells. These results indicate that the IF regimen enhances the TGF-β-producing ability of M2 macrophages and that the development of Tregs keeps mice healthy against ACD exacerbated by obesity. Therefore, the IF regimen may ameliorate inflammatory immune disorders caused by obesity.

Pediatric Contact Dermatitis: A 10-Year Multicenter Retrospective Study

Background: Although allergic contact dermatitis (ACD) is relatively common in the adult and pediatric populations alike, few studies describe the special features of contact sensitization among the Israeli pediatric populations, none of them is multicenter. Our study aims to describe and analyze patch test results and trends in 4 tertiary care centers between 2012 and 2022. Methods: We assessed the results of 357 patch tests performed on children 0-18 years old between 2012 and 2022 in designated clinics in 4 tertiary medical centers. All patients were tested using the European baseline series and additional series as clinically indicated. We assessed the demographic features, atopic features, and influence, as well as the main allergens to cause sensitization and allergic contact dermatitis among the pediatric population. Results: In total 69% of the study population were females, mainly 12-18 years old, 35% of the study population were previously diagnosed with atopic dermatitis, and 57% had an atopic diathesis. Females were more commonly sensitized (P < 0.05). Patients without atopic dermatitis were more commonly diagnosed with ACD and had more reactions on patch test (P < 0.05). The most common allergens to cause ACD are preservatives and metals, as previously described, however, acrylate sensitivity is an emerging group that has not been described among the Israeli pediatric population in previous studies. Fragrance mix 2 and Mroxylon pereirae are relatively rare allergens among the Israeli pediatric population, whereas linalool hyperoxide might be considered an emerging allergen. Methylisothiazolinone causes ACD more frequently among patients without atopic dermatitis (P < 0.05). Conclusions: Among the Israeli pediatric population, ACD is more common in females without atopic dermatitis. Acrylates become a common culprit and should be included in baseline series. Patients with atopic dermatitis are less frequently sensitized by methylisothiazolinone.

Patch test results in a Dutch paediatric population with suspected contact allergy: A retrospective cohort study

BACKGROUND

Allergic contact dermatitis (ACD) in paediatric patients is on the rise. Continuous identification of emerging allergens is of great importance to ensure accurate patch testing.

OBJECTIVES

To assess the frequency and relevance of contact sensitivity in children and adolescents and evaluate changes in sensitization rates in the last decade.

METHODS

All patients with suspected ACD who underwent patch testing at the Amsterdam University Medical Centers between 2015 and 2021 were included.

RESULTS

Of 439 patients tested with the European Baseline Series (EBS) and additional series, 334 (76%) patients had at least 1 positive reaction and 172 patients (39%) had 1 or more relevant positive reactions. If additional series would have been omitted, 20% of patients would have been underdiagnosed. Compared to patients tested between 1996 and 2013, reactions to metal allergens, isothiazolinones, methyldibromo glutaronitrile, carba mix, amerchol L-101, and benzophenone-4 were more frequently observed.

CONCLUSIONS

This study confirms the need for patch testing in paediatric patients suspected of having ACD. For accurate patch testing, it is advised to include additional series.

Discoid (nummular) eczema in the paediatric setting - An Australian/New Zealand narrative

Discoid (nummular) eczema is a common and distinctive eczema variant, which has not been studied in depth. Although the principles of management are similar to that of classic atopic dermatitis, distinctions are made due to its unique presentation and persistent clinical course in children. Australian and New Zealand dermatologists with an interest in paediatric eczema developed a consensus narrative to assist clinicians in diagnosing and treating this subtype of eczema. Identifying triggers, potent topical corticosteroids under occlusion, skin barrier support and management of pruritus are first-line therapies, however, many eventually require systemic immunomodulatory agents.

The Added Value of Patch Testing Beyond the Baseline Tray

BACKGROUND

The patch test is the standard for diagnosing allergic contact dermatitis. Standardized trays allow the examination of the most prevalent allergens, whereas customized trays are more appropriate for addressing specific allergens and require expertise. They are therefore usually performed in specialized clinics.

METHODS

We assessed the results of 4355 patch tests performed between 2012 and 2020 in a contact dermatitis clinic located in a large tertiary medical center. All patients were tested using the European baseline series and additional trays as clinically indicated. We assessed the frequency of relevant positive reactions outside the European baseline series. We then examined the added value and number of tests (NNTs) that need to be performed to elicit one relevant positive reaction per tray and common allergens.

RESULTS

Nine hundred fifty-four patients (21.9%) had 1 or more positive relevant reactions; 43.3% tested positive for an allergen outside the European baseline series (OEBS). The acrylate and fragrance trays were highly represented among the positive and relevant reactions OEBS with NNTs of 4.4 and 6.8, respectively. 2-Hydroxyethyl methacrylate is the most prevalent allergen OEBS and is considered a marker for acrylate sensitivity with a high rate of cross-reactions and concordance rate of 85%, justifying its addition to the EBS in 2018. Other highly represented allergens include chloramphenicol, 2-hydroxyethyl acrylate, and Amerchol L-101, a lanolin derivative. The cosmetics and textile trays, although often tested, have relatively low added values of 3.7% and 2.3%, respectively. Surprisingly, the cutaneous adverse drug reaction series tray (CAD-1000) yielded no positive reactions, whereas testing the patients' medication yielded positive results in 10.9% of the cases.

CONCLUSIONS

Expanded patch testing is crucial to accurately diagnose allergic contact dermatitis and almost doubles the number of patients with relevant positive reactions. Acrylate sensitivity is an emerging epidemic with a high positive reaction rate and low NNT, as is sensitivity to the allergens in the fragrance tray. 2-Hydroxyethyl methacrylate is a reliable marker for acrylate sensitivity with a concordance rate of 85%. Chloramphenicol is a common culprit and should be added to the standard tray in countries with a high usage rate. A low NNT was also observed when testing the patients' own cosmetics and medications; this should, therefore, be encouraged. The textile tray yielded a relatively high NNT; however, it should be performed when clinically indicated in the absence of a reliable marker in the EBS.

What We Have Learned–Milestones in Pediatric Contact Dermatitis

Purpose of Review

This review highlights recent developments in the field of pediatric allergic contact dermatitis (ACD) and patch testing. We will review updates on the pathophysiology of contact dermatitis, discuss new contact allergens, explore the impact of dupilumab on patch testing, and provide pearls for the diagnosis and management of ACD in children.

Recent Findings

ACD is not a single immunologic phenomenon but rather has contributions from multiple inflammatory pathways. Emerging contact allergens include ingredients found in “slime” toys, glucose monitors and insulin pumps, and electronic equipment. Data thus far suggests that patch testing results are generally reliable in the face of concurrent dupilumab use.

Summary

ACD is likely underrecognized and underdiagnosed in pediatric patients, including infants and young children. Providers should keep patient-specific factors and emerging trends in mind when addressing suspected ACD, consider contact dermatitis when they encounter challenging cases of atypical, refractory, or chronic dermatitis, and feel comfortable performing patch testing in children.

Patch-test results in terms of the recently recommended allergens in children and adolescents: A retrospective cohort study over 22 years from Turkey

BACKGROUND

A European pediatric patch-test series was suggested recently.

OBJECTIVES

To evaluate the patch-test results in children (<10-years-old) and adolescents (10- to 18-years-old) in Turkey, focusing on the clinical/occupational relevance and the diagnostic value of the recently suggested series.

PATIENTS AND METHODS

A retrospective cohort study on 317 consecutively patch-tested patients ≤18 years of age, between 1996 and 2017.

RESULTS

The contact sensitization rate was 46.1%. Allergic contact dermatitis (ACD) was diagnosed in 30.9%, comprising non-occupational (84.7%) and occupational (15.3%) ACD. Nickel was the leading allergen in almost every age group. Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was the clinically most relevant allergen, followed by p-phenylenediamine (PPD), ammonium persulfate, fragrance mix I, nickel sulfate, and mercury/mercury(II)amidochloride. Occupational ACD was most frequently seen in hairdresser apprentices (adolescents only) who were sensitized with PPD ± ammonium persulfate. ACD from MCI/MI increased to 5-fold, ammonium persulfate and mercurial compounds to 2-fold, and PPD to 1.7-fold after 2007. Almost one third of patients would be missed by testing only with the recommended allergens.

CONCLUSIONS

For patch testing in Turkish children and adolescents, we suggest additionally testing with ammonium persulfate, mercury/mercury(II)amidochloride, toluenesulfonamide formaldehyde resin, and polyethylene glycol, the latter as a marker for nitrofurazone allergy, in appropriate patients.

Pediatric allergic contact dermatitis. Part I: Clinical features and common contact allergens in children

Allergic contact dermatitis (ACD), a delayed hypersensitivity skin reaction to environmental allergens, has a prevalence that is similar in children and adults. However, diagnostic testing for ACD in pediatric populations accounts for less than one tenth of all patch tests. The relative infrequency of pediatric patch testing may be attributed to the difficulty in testing in this population, which includes a smaller surface area for patch test placement and maintaining cooperation during patch testing, especially in younger children. Diagnosis can be difficult in children because the appearance of ACD can mimic other common pediatric skin conditions, particularly atopic dermatitis and irritant contact dermatitis. Comprehensive history taking, guided by patient presentation, age group, and location of dermatitis, helps build clinical suspicion. Such clinical suspicion is one of the major reasons behind patch testing, with additional indications being recalcitrant dermatitis and dermatitis with atypical distribution. US pediatric data have shown the top allergens to be metals, fragrances, topical antibiotics, preservatives, and emollients. These trends are important to recognize to guide management and accurate diagnosis, because ACD tends to persist if the allergen is not identified and can affect patients' quality of life.