Clinical update on contact allergy

Registries in Clinical Epidemiology: the European Surveillance System on Contact Allergies (ESSCA)

Background: Disease registries rely on consistent electronic data capturing (EDC) pertinent to their objectives; either by using existing electronic data as far as available, or by implementing specific software solutions.

Objectives: To describe the current practice of an international disease registry (European Surveillance System on Contact Allergies, ESSCA, www.essca-dc.org) against different state of the art approaches for EDC.

Methods: Since 2002, ESSCA is collecting data, currently from 53 departments in 12 countries. Departmental EDC software ranges from spreadsheets to comprehensive “patch test software” based on a relational database. In the Erlangen data centre, such diverse data is imported, converted to a common format, quality checked and pooled for scientific analyses.

Results: Feed-back to participating departments for quality control is provided by standardised reports. Varying author teams publish scientific analyses addressing the objective of contact allergy surveillance.

Conclusions: Although ESSCA represents a historically grown, heterogeneous network and not one unified approach to EDC, some of its features have contributed to its viability in the last 12 years and may be useful to consider for similar investigator-initiated networks.

Allergic skin inflammation induced by chemical sensitizers is controlled by the transcription factor Nrf2

Allergic contact dermatitis (ACD) is induced by low-molecular weight electrophilic chemicals and metal ions. Chemical contact sensitizers trigger reactive oxygen species production and provoke electrophilic stress, leading to the accumulation of the transcription factor nuclear-related factor 2 (Nrf2) in innate immune cell types. The objective of this work was to identify the role of Nrf2 in the regulation of ACD. We used the local lymph node assay (LLNA) and the mouse ear swelling test (MEST) to study the role of Nrf2 in both the sensitization and elicitation phase in nrf2 knockout (nrf2(-/-)) and wild-type (nrf2(+/+)) mice. Five chemicals were used: two compounds known to react with cysteine residues, 2,4-dinitrochlorobenzene (DNCB) and cinnamaldehyde (CinA); one sensitizer known to exhibit mixed reactivity to cysteine and lysine residues, isophorone diisocyanate; and one reacting specifically with lysine residues, trimellitic anhydride and croton oil, a well-known irritant. In the MEST assay, DNCB (1 and 2%) induced a significant increase in ear thickness in nrf2(-/-) compared with nrf2(+/+) mice, suggesting a role for Nrf2 in the control of the inflammatory process. When DNCB was used at 0.25 and 0.5% or when mice were treated with CinA, inflammation was found only in nrf2(-/-) mice. In the LLNA, all chemical sensitizers induced an increase of lymphocyte proliferation in nrf2(-/-) compared with nrf2(+/+) mice for the same chemical concentration. These results reveal an important role for Nrf2 in controlling ACD and lymphocyte proliferation in response to sensitizers.

[Importance of epidemiologic surveillance in contact dermatitis: Spanish surveillance system on contact allergies]

The high prevalence of contact dermatitis means that this common medical problem has considerable personal, societal, and economic impact. Clinical and epidemiologic research is needed if we are to shed light on the real situation of contact dermatitis in Spain. In this article we will look at epidemiologic research from a practical point of view and analyze the role of the dermatologist in planning and designing studies. The advantages of multicenter studies are discussed, along with the roles of national and international surveillance networks. We present the Spanish Surveillance System on Contact Allergies, which serves as a bridge between Spanish dermatologists and the European Surveillance System on Contact Allergies. The present and future aims of the Spanish network are described.

The European Surveillance System of Contact Allergies (ESSCA): results of patch testing the standard series, 2004

BACKGROUND

The European Surveillance System on Contact Allergies (ESSCA) began in 2001 as project funded by a European Union grant to monitor and evaluate contact sensitization (CS) based on clinical data collected by participating European dermatology departments.

OBJECTIVES

ESSCA aims to detect trends in CS in an international patch test population, monitoring the frequency of CS to (standard series) allergens, evaluating the effectiveness of intervention (e.g. governmental regulations) and improving standardization of the patch test procedure on an international level.

METHODS

In 2004, 31 ESSCA dermatology departments in 11 European countries collected patch test results and medical histories of patients tested with the European Standard Series (ESS) or a local standard allergen series using the multilingual Winalldat/ESSCA database, the German Winalldat/Information Network of Departments of Dermatology (IVDK) database or a locally created database including the items of the ESSCA 'minimal data set'. Data were sent to the ESSCA data centre where they were imported, pooled, examined for quality and subsequently analysed.

RESULTS

The departments patch tested 11 643 patients with a standard series, and 44% of the patients tested positive to one or more substances of the ESS. Nickel sulphate, the fragrance mix, Myroxylon pereirae resin, cobalt chloride, potassium dichromate, methyldibromoglutaronitrile and paraphenylenediamine are (still) the most important allergens detected. Several additional substances tested on consecutive patients in some clinics were also examined. Among these allergens, propolis and Compositae mix had a relatively high CS prevalence.

CONCLUSIONS

The expanding ESSCA network continues to provide up-to-date information regarding the pattern of CS diagnosed in participating departments across Europe.

Skin contact irritation conditions the development and severity of allergic contact dermatitis

Irritant contact dermatitis (ICD) is a frequent inflammatory skin disease induced by skin contact with low molecular weight chemicals such as haptens endowed with proinflammatory properties. Allergic contact dermatitis (ACD) is a frequent complication of ICD and is mediated by hapten-specific T cells primed in lymph nodes by skin emigrating dendritic cells. The aim of this study was to analyze the relationship between ICD and ACD to 2,4-dinitrofluorobenezene (DNFB) in C57BL/6 and BALB/C mice, which develop a severe and a moderate skin inflammation, respectively. Upon a single skin painting with DNFB, C57BL/6 developed within hours a more severe dose-dependent ICD response as compared to BALB/C mice, which was associated with enhanced upregulation of IL-1beta, IL-6, and IL-10. Skin exposure to a low dose of DNFB resulted, in both strains, in a low ICD that resolved in a few hours. Alternatively, skin painting with either an intermediate or a high DNFB concentration induced an ICD that subsequently gave rise to an ACD reaction whose intensity was proportional to the magnitude of the ICD response and was more severe in C57BL/6 mice than in BALB/C mice. In conclusion, the hapten-induced skin contact irritation conditions the development and the severity of ACD.

Patch test results in patients with scalp dermatitis: analysis of data of the Information Network of Departments of Dermatology

BACKGROUND

Contact dermatitis of the scalp may develop primarily due to exposure to cosmetic products or secondarily due to application of topical medicaments on affected skin.

OBJECTIVES

To illustrate the current spectrum of allergens in scalp dermatitis.

PATIENTS/METHODS

Data of 1320 patients recorded by the Information Network of Departments of Dermatology (IVDK) between 1993 and 2003, who were patch tested to confirm or rule out (secondary) allergic contact dermatitis of the scalp, were analysed.

RESULTS

Sensitization to p-phenylenediamine, tolune-2,5-diamine, p-aminophenol, 3-aminophenol, p-aminoazobenzene, cocamidopropyl betaine and pyrogallol was significantly more common than in the remaining IVDK patients. In 690 patients, altogether 4070 patients' own products were patch tested. Medical products, hair tints and bleaches (HTB) and hair-cleansing products together caused nearly 2/3 of positive patch test reactions. Among these categories, HTB showed the highest percentage of positive patch test reactions; 24 of 29 HTB-positive patients had no positive reaction to any of the commercially available allergens.

CONCLUSIONS

In our subgroup of patients with scalp dermatitis, constituents of hair-colouring products were the most important allergens. As some ingredients of hair dyes are not contained in patch test series, testing of patients' own products is an important part of diagnostic workup, as otherwise sensitizations may be missed.

CD8+ T Cells Are Effector Cells of Contact Dermatitis to Common Skin Allergens in Mice

Allergic contact dermatitis (ACD) to strong experimental haptens is mediated by specific CD8+ T cells. Here, we show that similar mechanisms occur for weak haptens, which comprise the vast majority of chemicals responsible for human ACD. We used a model of ACD, that is, the contact hypersensitivity reaction, to test for the allergenicity of three weak haptens involved in fragrance allergy. ACD to weak haptens could not be induced in normal mice. In contrast, mice acutely depleted in CD4+ T cells developed a typical ACD reaction to the three weak fragrance allergens that peaked 24 hours after challenge. Priming of CD8+ T cells was observed in draining lymph nodes 5 days after sensitization and development of ACD was associated with the infiltration of activated CD8+ T cells in the challenged skin. CD8+ T cells were effectors of the ACD reaction as in vivo treatment with depleting anti-CD8 mAbs abrogated the ACD responses and as purified CD8+ T cells could adoptively transfer ACD to naive recipients. In conclusion, our data demonstrate a dominant role of CD8+ T cells as initiators of ACD to weak haptens, and suggest that CD8+ T cells may represent potential targets for preventing or treating ACD.