Contact Dermatitis最新文献

Background: Hair cosmetic products contain various chemicals which are partly potent contact sensitizers. These may cause occupational hand eczema in hairdressers, but also scalp and face dermatitis in consumers.

Objective: To (i) highlight differences between the spectrum of occupational and non-occupational exposure reflected in sensitization, and (ii) correlate trends in the last decades with regulatory interventions (or the lack thereof).

Methods: Patch test and clinical data collected by the IVDK (https://www.ivdk.org) between 01/1995 and 12/2020 were subjected to a pooled re-analysis. Age-stratified sensitization prevalences in female hairdressers and consumers, respectively, were calculated for 2-yearly intervals spanning the study period. Log-binomial regression models were employed to estimate the association between contact allergy and (i) subgroup (hairdresser vs. consumer), (ii) a 3-level age category, and/or (iii) time period, respectively.

Results: Hair dyes were the most frequent sensitizers in hairdressers and consumers; however, there was a marked increase in (particularly the young) consumers. Pyrogallol had been banned in 1992 but still elicited positive patch test reactions even in the young. Hydroquinone, banned in 2013 in dyes, showed no decline in sensitization prevalence. Glyceryl thioglycolate has been withdrawn and later banned in Germany since around 1995, which caused contact allergy prevalence to drop to almost zero in the youngest age group, largely until today.

Conclusion: As a limitation, putatively differing selection for patch testing render prevalences difficult to compare between hairdressers and consumers. The importance of hair dye allergy is evident, needing continued efforts to increase product safety from the manufacturing and regulatory side. The potential of (self-)regulatory intervention is well illustrated by the decline of contact allergy to glyceryl thioglycolate.

Background: The vast majority of allergic tattoo reactions involve red-shaded tattoos without a causal explanation.

Objective: To determine rosin oxidation products (ROPs) in pigments and tattoo inks as a hypothesised source of tattoo allergenicity.

Materials and methods: Content of pigment samples (n = 112) and tattoo inks (n = 119) was analysed using newly developed UHPLC/PDA/MS methods, XRD and high-resolution MS.

Results: ROPs were found at varying levels in 32 pigments and 38 tattoo inks. The mean ROP level of red inks was approximately three-fold higher than that of non-red-spectrum inks. Among 24 red-spectrum inks with ROPs, azo pigments PR170, PR266, PR22, PY74 and quinacridones PR122 and PV19 were frequently identified. PR170 was present in 21 of those inks.

Conclusions: To explain results, a manufacturing model was developed showing rosination pathways, with only some having likely allergenic outcomes. Inks whose pigments were produced with rosin incorporated and/or irreversibly bound are the most likely to be allergenic. ROPs within those inks are believed to remain in the body after tattooing, acting as haptens. This view is consistent with biopsy reports of allergic reactions to red-shaded tattoos. We propose that ROPs may be at least partially responsible for those reactions. Pending proof of this proposal, tattoo-ink manufacturers might choose to avoid rosinated pigments.

Background: Sodium lauryl sulfate (SLS) has been included as an irritant control in the baseline patch test series of the German Contact Dermatitis Research Group (DKG) for two decades, although its diagnostic value remains controversial.

Objective: To evaluate the strengths and limitations of SLS as an irritant control in patch testing.

Methods: We retrospectively analysed data from 43 478 consecutive patients patch tested with 0.25% SLS aq. and 189 allergens within the IVDK network. SLS reactions were graded from 1 (weak) to 5 (strong). Associations between SLS reactivity and allergen-specific responses were examined.

Results: Overall, 22.4% of all patients reacted positively to SLS, most with weak erythema (SLS 1). Stronger SLS reactions (SLS 2-5) were associated with male sex, age ≥ 40 years, occupational dermatitis and hand dermatitis. Positive SLS reactions correlated with several allergens of high irritative potential, notably cocamidopropyl betaine, formaldehyde, sorbic acid and diphenylguanidine. In contrast, plant-derived allergens showed weak or inconsistent associations. Importantly, grading SLS reactions (1-5) did not improve diagnostic discrimination compared to a simple positive/negative classification.

Conclusion: While SLS can indicate skin irritability for certain allergens, it is not a universal marker. Our large-scale analysis supports binary SLS classification and provides a robust evidence base for the ongoing debate on whether and how irritant controls should be used in patch testing.

Background: Skin barrier impairment is central to irritant (ICD) and allergic contact dermatitis (ACD). Stratum corneum (SC) components cholesterol sulphate (CholSulph), glucosylcholesterol (CholGlc) and natural moisturising factor (NMF) are critical for barrier function, but their changes in ICD and ACD remain underexplored.

Objectives: To measure CholSulph, CholGlc, NMF and IL-1α in patch-induced ICD and ACD and in hand dermatitis (HD) diagnosed as ICD or ACD.

Methods: SC samples were collected from HD patients undergoing patch testing. Biomarkers were analysed in positive reactions to sodium lauryl sulphate (ICD, n = 44), allergens (ACD, n = 113; nickel, chromium, methylisothiazolinone [MI]), lesional HD skin (n = 45) and control (empty chamber, n = 121).

Results: CholGlc was significantly elevated in patch-induced ICD and ACD. CholSulph was increased in ICD and chromium- and MI-induced ACD. NMF decreased in ICD, while IL-1α decreased in ICD and chromium ACD. Chromium induced the strongest response, nickel the weakest. In HD, ICD and ACD showed elevated CholGlc, reduced NMF and IL-1α, with CholSulph increased only in ACD. No biomarker differences were detected between clinical ICD and ACD.

Conclusions: Both induced and clinical ICD and ACD show consistent SC biomarker changes reflecting barrier dysfunction, with no differences between clinical ICD and ACD.

Whether atopic dermatitis (AD) is associated with an altered susceptibility to contact sensitization (CS) remains debated. The aim of this systematic review and meta-analysis was to provide updated estimates of the association between AD and CS overall, by population type (general or referred), various demographics and selected allergens. PubMed, Embase and Web of Science were systematically searched for studies published between 2016 and 2025 reporting CS prevalence in individuals with and without AD. Data were combined with a previous systematic review covering studies published between 1982 and 2016. Meta-analyses were performed to calculate pooled odds ratios (ORs). The pooled analyses showed no overall association between AD and CS (OR 1.08, 95% CI: 0.82–1.42), including in referred populations (OR 1.03, 95% CI: 0.76–1.38). In general population studies, CS prevalence was higher among individuals with AD. The association was statistically significant in children and adolescents (OR 1.34, 95% CI: 1.0–1.80) but not in adults. Positive associations were found between AD and CS to Compositae mix and sesquiterpene lactone mix, but not to nickel, cobalt, or chromium. In conclusion, our findings suggest no general association between AD and contact CS, but multiple factors may modify this relationship, underlining the value of patch testing in AD.

Background: Chronic actinic dermatitis (CAD) is a photodermatosis associated with contact allergy. Changes in the contact allergen profile in patch-tested CAD patients from our department have been reported over several decades.

Objectives: To determine the frequency of positive patch tests and allergen profiles in recently investigated CAD patients and compare this to profiles in earlier decades.

Methods: A retrospective cohort study was undertaken at a tertiary Cutaneous Allergy department between 2011 and 2021. Demographics and 10 allergens with highest positivity in CAD and non-CAD patients were compared.

Results: Patch testing was performed in 309 (88.3%) of 349 CAD patients, with 186 (60.2%) testing positive to any allergen and 8 (2.6%) positive on photo-patch testing. Patients aged > 40 and with Fitzpatrick skin type V-VI were statistically more likely to be patch test positive (age > 40: p = 0.0082; Fitzpatrick skin type: p = 0.0361). Sesquiterpene lactones (SQL) (6.8%) and formaldehyde (4.8%) were amongst the top 10 most frequently positive allergens in CAD but not in non-CAD patients.

Conclusion: Allergic contact dermatitis remains prevalent amongst CAD patients, although sensitisation to allergens historically linked to CAD is decreasing. The cause of this is unclear but potentially due to changes in environmental exposures, particularly in younger CAD patients.