Allergic contact dermatitis (ACD) is increasingly recognized in the pediatric population. Although patch testing is the gold standard for diagnosis, the absence of standardized, evidence-based pediatric patch test panels and limited access to comprehensive allergen series in many settings pose significant diagnostic challenges. This study aimed to evaluate a practical and shortened patch test panel suitable for children with ACD. The clinical characteristics and patch test results of pediatric patients diagnosed with ACD between 2017 and 2021 were retrospectively analyzed. Patch testing was performed using the Thin-Layer Rapid-Use Epicutaneous (T.R.U.E.) Test, and allergen positivity was evaluated according to age groups. A total of 86 children were included (54.7% girls), with a mean age of 7.7 ± 3.7 years (range: 1-17 years). Nickel was the most frequently detected allergen across all age groups. Formaldehyde resin, cl+me+isothiazolinone, and fragrance mix were the most common allergens in children aged 1-6 and 7-12 years. A patch test panel consisting of 14 allergens was sufficient to identify relevant sensitizations in all age groups. Standard patch test panels are often difficult to apply in children due to limited body surface area and practical constraints. Shortened, targeted patch test panels containing the most relevant allergens may improve diagnostic feasibility, particularly in pediatric patients and in settings with limited access to extensive allergen series.

Patch test results obtained with the European Baseline Series (EBS) in its current version serve both contact allergy surveillance and (re-)assessing the diagnostic value of EBS allergens. To present results of current EBS patch testing, obtained in 59 departments in 14 European countries during 2021 and 2022. Anonymised or pseudonymised individual data, and partly aggregated results, on demographic/clinical characteristics and patch test results with the EBS were prospectively collected, centrally pooled, and retrospectively analysed. In 2021 and 2022, 18 832 patients were patch tested with the EBS. Sensitization to nickel remained most common (18.85 (18.29-19.43)% positivity (95% confidence interval)). Fragrance mix I and Myroxylon pereirae resin yielded very similar results with 6.39 (6.04-6.76)% and 6.5 (6.15-6.87)% positivity, respectively. Concerning preservatives, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) 0.02% aq. yielded 5.52 (5.11-5.96)% and MI 0.2% aq. yielded 5.28 (4.94-5.64)% positives. Testing formaldehyde 2% aq. identified almost one percentage point more positive reactions than 1% aq. (2.05 (1.81-2.32)% vs. 1.22 (0.99-1.48)). Positive reactions to the recently added allergens were most frequently seen to propolis (5.47 (5.12-5.84)%) and 2-hydroxyethyl methacrylate (3.63 (3.32-3.96)%). Compared to the previous reporting period, surveillance results with the EBS were mostly stable. The results regarding Quaternium 15 (0.4 (0.29-0.53)% positives) justified its exclusion from the 2023 EBS version.

Revisiting Contact Sensitization Among Patients With LPP/FFA: Cross-Sectional Findings From 55 Cases.

Patch Test Reactions Associated with Food Sources: A Retrospective Analysis of the North American Contact Dermatitis Group Data (2001-2018).

Background: Allergic scalp contact dermatitis (ASCD) is a delayed type of hypersensitivity from contact with a specific allergen to which the patients has developed a specific sensitivity. The aim of the study was to evaluate the results of patch testing with standard series of contact allergen in patients suspected to have ASCD. Methods: 112 cases of scalp contact dermatitis were included in the study. Test substances were applied on the upper part of the patient's back, on clinically uninvolved and untreated skin. The patch test was removed and reaction were evaluated after 48 h and 72 h. The grading of negative (-) to positive (+ to ++++) patch test was done in accordance with the International Contact Dermatitis Research Group. Results: Among the 112 cases, 83 patients were female (74.1 %) and 29 were male (25.9 %). The age of participants spanned 17 to 72 years. The commonest age group affected was 41-50 years. The most common positive reactions were recorded to nickel sulphate 22 (26.2%), cobalt chloride 18 (21.4%), fragrance mix 16 (19%), balsam of Peru 14 (16.7%), carba mix 8 (9.5%) and paraphenylenediamine 5 (5.9%). Females were more likely to show a positive response to two or more allergens. Scalp itching or burning were reported as the most common symptom. Conclusions: Scalp ACD predominantly affects middle-aged women. Our results suggest that nickel sulphate and cobalt are the predominant allergens responsible for the induction of ASCD. These findings are crucial in the treatment, long term management, and education of patients with ASCD.

Objectives: The aim is to study the clinical profile of occupational dermatoses and to assess the impact on the quality of life (QOL; Dermatology life quality index /DLQI) of health care worker (HCW). Materials and Methods: This was a cross sectional study conducted between 2020 to 2022 that included 78 HCW with occupational dermatoses (OD). Patch test was done using Indian standard series, supplemental allergens, and substances as it is wherever clinically indicated. Results: The majority of HCWs were nursing officers, accounting for 33 (42.3%), followed by doctors, who constituted 30 (38.5%). A significant portion of these professionals, 50 (64%), were engaged in COVID-19 care settings, including both intensive care unit (ICU) and non-ICU environments. Irritant contact dermatitis (ICD) was found in 46 cases (58.97%), while allergic contact dermatitis (ACD) was identified in 8 cases (10.25%). The remaining cases included mask acne, pressure indentations/erythema, frictional blisters, contact urticaria, contact leukoderma, and Koebnerization of psoriasis. Among the 54 patients who underwent patch testing, 16 were found to be sensitive to various allergens such as fragrance mix and chlorocresol. OD had a mild to moderate impact on the quality of life for most of these HCWs. Conclusion: HCWs are exposed to many irritants and allergens such as gloves, sanitizers, person protective equipment (PPE), disinfectants, chemicals(laboratory). In the present study contact dermatitis (CD), frictional dermatoses (FD) were commonly observed. Gloves, sanitizers, mask were most frequently observed contactants. OD had small to large impact on QOL. The importance of understanding OD should be highlighted among dermatologists and HCWs.

Analysis of European Baseline Series Patch Test Results in Adult Patients in Adana Province, Turkey; Single Center Experience.

Evaluating Copositivity Patterns in Fragrance/Botanical Patch Testing through Hierarchical Clustering and Network Analysis.

Allergic contact dermatitis (ACD) in the elderly is influenced by age-related immunological changes, cumulative exposure, and skin barrier alterations. However, data comparing sensitization profiles among different geriatric populations remains limited. We aimed to evaluate and compare the patterns and severity of patch test reactions in patients aged 65-74 (young-old group) and those aged 75 years or older (old-old group), using the European Standard Series (ESS). A total of 128 patients aged 65 years or older were retrospectively analyzed. Patch testing was performed with the ESS, and reactions were assessed at 48 and 96 hours according to the International Contact Dermatitis Research Group (ICDRG) criteria. Of the patients, 106 were classified as young-old and 22 as old-old. The most frequent allergens in the young-old group were propolis (20%), fragrance mix I (17%), methyldibromo glutaronitrile (16%), peru balsam (15.1%), and nickel sulfate (14.2%), while methylchloroisothiazolinone/methylisothiazolinone (22.7%), methylisothiazolinone (13.6%), propolis (13.6%), and textile dye mix (13.6%) were the most common that in the old-old group. Across both groups, preservative and fragrance-related allergens predominated. According to ICDRG grading, most reactions were weak positive (+), whereas moderate positive (++) and strong positive (+++) reactions were less frequent, particularly in the old-old group. In conclusion, preservatives, propolis and fragrance-related allergens remain the leading causes of contact sensitization in the elderly, while metal sensitization decreases with advancing age. The reduced frequency and intensity of positive reactions in the old-old group may reflect immunosenescence and diminished T-cell responsiveness in advanced age.

Woodworkers (WW) are exposed to a wide range of occupational hazards and potent allergens. To describe the contact sensitisation pattern of WW with occupational dermatitis (OD). In a retrospective study, patch test and clinical data collected by the Network of Departments of Dermatology (IVDK) from 1999 to 2023 were analysed. Data of 471 WW with OD (89.6% male) were compared with data of 558 WW without OD and 39 759 patients from other occupational groups (non-WW) with OD. Allergic contact dermatitis (32.5%) was the most frequent diagnosis among WW with OD. Hands (63.5%) were predominantly involved. Face dermatitis (8.5%) and dust exposure (36.6%) as contributing factors were significantly more common than in non-WW with OD. Sensitisations to epoxy resin (5.5%) were significantly more frequent in male WW with OD than in male WW without OD. Other frequent sensitisations included those to Myroxylon pereirae (7.4%), propolis (5.6%), and colophonium (5.3%). Sensitisations to chromium, cobalt, thiuram mix, fragrance mix II and compositae mix II were significantly less frequent than in male non-WW patients with OD. Allergic contact dermatitis is frequent in WW with OD. Important allergens include resins and plant-derived substances. Airborne OD may interfere with prevention efforts.

Elucidating the Relationship Between Mycosis Fungoides and Contact Sensitization: A Retrospective Study.

Relevance of Socioeconomic Status in Contact Dermatitis: Insights from a Retrospective Study.

Translated article] Should Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde (Lyral®) Still be Part of the Baseline Series?

BackgroundPara-phenylenediamine (PPD) is a major hair dye allergen and often heralds broader contact allergy risk, yet the links among PPD sensitization, polysensitization (PS) and host genetics remain understudied.ObjectiveTo quantify the association between PPD sensitization and PS in Korean patch test patients and to explore whether single nucleotide polymorphisms (SNPs) in selected immunoregulatory genes modulate this relationship.MethodsWe retrospectively analysed 647 Korean patients patch tested with the Korean Standard Series. PS was defined as reactivity to ≥3 unrelated allergens; simultaneous positives to nickel, cobalt or chromate were counted as one event. Independent predictors of PPD sensitization were determined by multivariable logistic regression, and allergen networks were visualised with heatmaps. Seventeen patients were genotyped for SNPs in tumor necrosis factor-alpha, CXCL11, interleukin (IL)-10, IL-16 and STAT6.ResultsPPD sensitization was confirmed in 38 patients (5.9%) and remained independently associated with PS (adjusted odds ratio [OR], 2.72; 95% confidence interval, 1.11–6.67). Additional chemical predictors were mercury ammonium chloride (OR, 3.68; p=0.018) and fragrance mix I (OR, 3.18; p=0.013). Heatmaps revealed dense preservative and rubber allergen clusters in PPD positive and particularly PS positive subsets. Exploratory genotyping showed numerical differences in CXCL11 variant frequency in PPD+/PS+ patients (85.7%) compared to expected population frequencies (about 50% in East Asians), though the small sample size (n=17) precluded statistical significance testing.ConclusionPPD sensitization identifies patients at increased risk for PS and reactivity to mercury compounds and fragrance-related substances. Preliminary genetic observations require validation in larger studies to determine potential immunogenetic contributions.

Skin aging causes various immunological and structural changes and increases the risk of many skin diseases such as contact dermatitis. Our aim was to share the allergen contact dermatitis sensitivities of the elderly population with the European baseline series (EBS) results. Patients aged 65 years and older who were patch tested with EBS in the immunology and allergy clinic between January 1, 2018, and March 1, 2025, were included in the study. The median age of the 62 patients included in the study was 69.5 years (25-75, 66.0-73.3 years); 54.8% of the patients were female; and 82.3% of the patients were under the age of 75. The rate of at least one positive patch test was 41.9%, and no positivity was observed in approximately half of the allergens included in the EBS. The rate of at least one positive test result was 37.3% in the 65-74 age group and 63.6% in the 75-84 age group (p = 0.177). The rate of at least one positive test result was 35.3% in women and 50% in men (p = 0.243). The most common allergen over the age of 65 was fragrance mix I (11.3%), followed by potassium dichromate (9.7%) and fragrance mix II (9.7%) in equal proportions. It is also very necessary to create an "elderly baseline series" by avoiding unnecessary allergens that are not detected as positive in patch tests. In addition, increasing the number of studies in geriatric patients will help in understanding trends in contact allergy.

Abstract para-Phenylenediamine (PPD) in black henna tattoos is a well-known sensitizing agent causing allergic contact dermatitis; however, the safety of other products used in temporary tattoos is limited. Jagua and jagua henna temporary tattoos are becoming increasingly popular, owing to claims of these being natural, safe and free from PPD. Jagua temporary tattoo is made from genipin, an extract from the sap of the unripe fruit of Amazonian tropical Genipa americana or South East Asian Gardenia jasminoides. Extracts of G. americana fruits have been used by indigenous Amazonian people for its dyeing properties and also in traditional Chinese medicine for centuries. On the skin, genipin binds to epidermal proteins to form dark blue or black pigment that can last up to 10 days (Wilmot MC, Wakelin SH. Allergic contact dermatitis caused by jagua temporary tattoo. Clin Exp Dermatol 2020; 45: 261–2). It can be used alone in jagua temporary tattoos or mixed with henna paste. Genipin is also currently used for its crosslinking effect in the manufacture of polysaccharides, and is being investigated for its anti-inflammatory properties. We present the case of a 29-year-old female patient seen in the cutaneous allergy clinic for a severe painful blistering rash that developed 2 days after application of jagua henna on her hands and forearms. The rash worsened over several days with significant oedema, erythema and vesiculations. She had performed a localized test patch 28 days prior to jagua henna application, which did not show any reaction. She had used natural henna and dyed her hair on previous occasions with no reactions. She required treatment with a 7-day course of oral steroid, flucloxacillin and fexofenadine as it was not responding to topical steroid creams. Patch testing was performed to the British baseline series, and also to cosmetics, fragrances and hairdresser series. Her own products were applied, which included jagua henna and eucalyptus henna. The patch test result came back entirely negative to PPD and toluene-2,5-diamine at day 2 and 4; however, there was a strong positive reaction to jagua henna and a weak positive reaction to eucalyptus henna. The patch tests also showed positive reactions to balsam of Peru, fragrance mix I, hydroperoxide of linalool, and 2-n-octylisothiazolinone. We report a case of allergic contact dermatitis caused by jagua henna temporary tattoo, which highlights the presence of an emerging allergenic substance ‘genipin’ used in temporary tattoos.

Abstract Allergic contact dermatitis (ACD) in children and adolescents is an important diagnosis that can cause significant morbidity. They are a distinct cohort from the adult population due to exposure to different allergens. In cases where a relevant result is identified, avoiding the allergen can be a simple and effective management. Children are patch tested in fewer numbers than adults and it is likely that the prevalence of ACD in this population is underestimated. Potential reasons for this may be perceived difficulties in children tolerating testing, and the high prevalence of atopic eczema in children, which has a similar presentation to ACD. All paediatric patients undergoing patch testing over a 6-year period (January 2019 to December 2024) in two specialist cutaneous allergy centres were included in this retrospective review. Relevant data were extracted from patch test departmental records and electronic notes. Patch test readings were performed on day 2 and day 4 in accordance with the International Contact Dermatitis Research Group and European Society of Contact Dermatitis guidelines. In total, 240 patients were included (70 male, 170 female), with an average age of 13 years at the time of patch testing (age range 3–17 years). Overall, 75% (179) had a personal history of atopy. The most common hobbies were the gym, swimming, football, gaming, netball, piano, and arts and crafts. One-quarter (25%, 61) of patients asked had been exposed to one or more potentially ‘risky behaviours’ (hair dye: 27, artificial nails: 41, black henna tattoo: 31), with the youngest exposed aged 10 years. In total, 47% (112) presented with facial dermatitis, most localized to periorbital or perioral areas or both. Overall, 18% (44) presented with hand dermatitis and 7% (17) were referred to investigate a specific trigger such as sunscreen. Patch testing was positive in 50% (120) of patients. Of those with a positive reaction 67% (79) had a history of atopy. In patients with multiple positive patch tests 93% (37 of 40) were atopic. Positive relevant allergens are categorized in the Table, with the most common allergens listed. Our results highlight the importance of patch testing in atopic and nonatopic children. The most common relevant causes of paediatric ACD in our cohort were fragrance, preservatives, metals and lanolin.TableThe most common currently relevant allergens in paediatric patients (n = 120)Fragrances38% (45)Linalool19% (18)Fragrance mix I7% (8)Balsam of Peru6% (7)Limonene5% (6)Preservatives31% (37)MI12% (14)MCI/MI10% (12)Metals10% (12)Nickel6% (7)Wool alcohols10% (12)Acrylates9% (10)Medicaments9% (10)Rubber7% (8)Carba mix 3%4% (5)Sunscreens4% (5)MCI, methylchloroisothiazolinone; MI, methylisothiazolinone.

Abstract Cananga oil and ylang ylang oil are essentials oils used in perfumed products such as cosmetics, soaps and perfumery. The haptens ‘cananga oil, C-002’ and ‘ylang ylang oil (Cananga odorata), Y-001’ are available from Chemotechnique for patch testing. The preparations are steam distilled from flowers of the cultivars Cananga odorata macrophylla (C-002 cananga oil) and Cananga odorata genuine (Y-001 ylang ylang). The two haptens have different Chemical Abstracts Service (CAS) registry numbers – unique identifiers assigned to chemicals described in scientific literature, but share the same International Nomenclature of Cosmetic Ingredients (INCI) name, that is Cananga odorata, although compositional data reveals limited concordance. Between 2008 and 2024, we patch tested (in a targeted manner) 1059 patients to a fragrance and essential oil series including Y-001 and C-002, recording the results on a database. We reviewed our results, looking at the frequency of positives, notably to determine overlap, and hence whether testing to both is required. Most of those tested were female (82%), and the median age was 44 years. Facial involvement was reported in 56%. We found allergic positives in 11 (+/++/+++) to Y-001 (1.04%), 10 to Y-001 alone (0.94%), five (+) to C-002 (0.47%) and four (0.38%) to C-002 alone. One patient was positive to both Y-001 and C-002. One woman reacted to her own ylang ylang oil (cultivar not declared) – she was negative to Y-001 but positive to C-002. Fourteen (93%) of those positive to either Y-001 or C-002 reacted to at least one other fragrance (all of the Y-001 group; four of five of the C-002 group) – see the Table below. However, three were negative to fragrance markers in the British Standard Series. The 1% pickup rate for Y-001 supports its inclusion in a targeted fragrance series. Minimal concomitant reactions to C-002 – only one of 11 – means that both Y-001 and C-002 should be tested. They seem to have different constituent allergens. If only the British Standard Series had been used, contact allergy would have been missed in a significant proportion of cases.TablePositive reactions to other allergens in those testing positive to Y-001 or C-002 Positive to Y-001 (n = 11)Positive to C-002 (n = 5)Fragrance mix I74Fragrance mix II10OH- linalool 0.5/1%02OH- limonene00Myroxylon pereirae62HICC (hydroxyisohexyl 3-cyclohexene carboxaldehyde)10Isoeugenol74Eugenol22Oakmoss absolute30Balsam of Tolu61Clove oil33Lemon grass oil33Neroli oil20Lavender absolute10Cedarwood oil32Tea tree oil11

The Clinical Phenotype of Patients with Contact Polysensitization, a Retrospective Cohort.

Background/Objectives: Patch testing is a valuable clinical tool for identifying the causes of allergic contact dermatitis (ACD). This study aimed to identify common allergens in southern Taiwan. Methods: A retrospective review of patch test data from April 2019 to May 2023 was conducted at a tertiary medical center. The European Baseline Series of allergens was utilized to evaluate and identify the causes of dermatitis. The prevalence rates of contact sensitization to each allergen were calculated. Results: A total of 57 patients (mean age 41.8 years) with contact dermatitis who underwent patch testing were included. The most common allergens were cobalt chloride (24.6%), followed by fragrance mix I (19.3%), Peru balsam (17.5%), nickel (II) sulfate hexahydrate (15.8%), benzisothiazolinone (15.8%), 4-Phenylenediamine (PPD) base (10.5%), and methyldibromo glutaronitrile (10.5%). Patients with positive patch test results frequently had a history of allergic rhinitis (26.3%), atopic dermatitis (24.6%), urticaria (21.1%), and elevated immunoglobulin E (IgE) levels (28.1%). The hairdressing profession was associated with a higher risk of hand eczematous dermatitis. Conclusions: Positive patch test results were observed in 86% of patients diagnosed with contact dermatitis. This study found that cobalt, rather than nickel, was the most prevalent allergen in patients with contact dermatitis. Elevated IgE levels were observed in ACD patients, with the hands being the most frequently affected area. Occupations as accountants, secretaries, and in the hairdressing and cosmetics industries were strongly associated with hand eczematous dermatitis. The early identification of allergens and appropriate treatment strategies significantly reduced recurrence rates and improved outcomes. For individuals with specific allergies, ongoing avoidance of identified allergens is crucial to managing and preventing allergic reactions. Further research is needed to elucidate the mechanisms and responses to novel therapies, including biologic agent- and nanotechnology-based treatments.