Genital contact dermatitis

Allergic skin diseases

BACKGROUND AND OBJECTIVESContact allergy is associated with a significant morbidity all over the world. This study was performed to investigate the pattern of sensitization by contact allergens in the local population.DESIGN AND SETTINGRetrospective study to investigate patch test reactivity among patients with clinical diagnosis of contact dermatitis who were referred to the allergy clinic at the King Khalid University Hospital, Riyadh, between April 2008 and March 2010.PATIENTS AND METHODSOf the 196 patients referred to the allergy clinic over the 2-year period, 91 (46.4%) patients reacted to one or more patch test allergens, and these patients were included in this study. The study group included 82 (91.1%) of Saudi nationality and 9 (8.9%) patients of other nationalities. The patch test was performed using the T.R.U.E TEST, containing 24 allergens/allergen mixes.RESULTSOf the 91 cases who reacted positively to one or more allergens, 67 (73.6%) were females with a mean age of 37 (8.3 years) and 24 (26.4%) were males with a mean age of 34 (11.6 years). Thirty-three (36.2%) patients reacted to nickel sulfate, 14 (15.3%) to p-phenylenediamine, 13 (14.2%) to p-tert-butylphenol-formaldehyde resin, 13 (14.2%) to thimerosal, and 9 (9.8%) to colophony. Reactivity against the rest of the allergens was not remarkable. A significantly higher percentage of females reacted to nickel sulfate (84.8% vs 15.2% in males; P=.0001), p-tert-butylphenol-formaldehyde resin (92.3% vs 7.7%; P=.0001), and thimerosal (76.9% vs 23.1%; P=.03).CONCLUSIONSPatch test reactivity to nickel sulfate was high. The pattern of contact allergy observed in this study indicates the need for large-scale investigations to identify local allergens responsible for contact allergy and for formulation of policies directed towards avoidance of exposure.

Differentiating between eczema caused by atopic dermatitis (AD), allergic contact dermatitis (ACD) or irritant contact dermatitis (ICD) remains clinically challenging. Histopathology and immunophenotyping often lack specificity, while skin cytokine profiling shows promise for molecular characterization.1 ICD results from exposure to irritants and activates the innate immunity, inducing cytokines such as IL-1α/β, IL-6 and tumour necrosis factor alpha (TNFα). ACD involves sensitization to allergens and triggers both innate and adaptative responses, with mixed T helper (Th)1/Th2 involvement.2, 3 AD, a chronic inflammatory skin disease marked by recurrent eczema and itching, is typically Th2/Th22-driven. Although IL-20 family cytokines have been implicated in ACD and AD models,4, 5 their role in ICD remains unclear. This study aimed to evaluate skin expression of Th-associated (IFNγ, IL-4, IL-9, IL-13 and IL-17), IL-20 family (IL-19, IL-20, IL-22 and IL-24) and inflammatory cytokines (IL-6 and TNFα) in differentiating AD, ACD and ICD. Forty-two patients were included: (i) 20 with ACD confirmed by positive patch tests to nickel, fragrance mix I, and/or methylisothiazolinone; (ii) 12 patch tested with sodium lauryl sulphate (SLS) to reproduce ICD; and (iii) 10 with AD presenting with untreated acute lesions. AD patients had a median age of 35 years, were mostly male (60%), with severe disease (median SCORAD 55.0) and classical AD phenotype (90%). ACD and ICD participants had no history of atopy. Cytokine mRNA expression in lesional and non-lesional skin was quantified using qRT-PCR. Study methods, statistical analyses, cohort details and patch tests results (Tables S1–S3) are provided in Online Repository (available at https://zenodo.org/records/16276888). This prospective study was conducted from 2012 to 2024 in a Belgian tertiary university hospital, with ethical approval. In non-lesional skin, only IL22 expression was significantly increased in AD compared with ACD and ICD. Other cytokines showed no significant differences across groups (Figure 1). SLS induced all cytokines, except IL4 (Figure 2; Table S4). Allergen exposure in ACD induced stronger cytokine expression than SLS in ICD, with the most notable increases in IL4, IL9 and IL22, evident as early as 24 h (Figure 2; Figure S1; Table S4). Cytokine expression was unaffected by patch test reaction severity or allergen type (Figures S2–S4). In lesional AD skin, IL4 was the only cytokine not induced compared with non-lesional skin (Figure 2; Table S5). IFNγ and IL9 induction was significantly higher in ACD than AD, while IL20 family cytokine expression was increased in both, with no significant differences (Figure 2; Figure S1). IL13 and IL17 induction did not vary significantly across groups (Figure 2; Figures S1 and S4). Our results support that ACD is characterized by strong induction of IFNγ, IL4, IL9 and IL20 family cytokines, highlighting a more complex Th response than a simple Th1/Th2 polarization.3 IL4 and IL9 emerged as key discriminatory markers between ACD and ICD. Moreover, the weak cytokine expression observed in ICD aligns with its innate-dominated nature. IL-20 family cytokines, together with Th1/Th2/Th9-associated cytokines, play a key role in ACD inflammation, supporting previous findings.4, 6, 7 In AD, IL22 was significantly increased in non-lesional skin compared with ACD and ICD, and IL20-related cytokines were increased in lesional AD skin. These results align with existing evidence implicating IL-22 and IL-24 in AD pathogenesis and support the rationale for IL-22-targeted therapies.8-10 However, because IL20 family cytokine levels were similar in AD and ACD, only IFNγ, IL4 and IL9 could differentiate them. In conclusion, combining IFNγ, IL4, IL9 and IL20 family cytokines enhances diagnostic precision in eczematous lesions. Th1/Th2/Th9 cytokines, particularly IL4 and IL9, help distinguish ACD from AD and ICD, while IL22 and IL24 differentiate ICD from AD. Skin cytokine analysis offers valuable diagnostic insight, but should always complement clinical evaluation, given the complexity of overlapping phenotypes in some patients. This study and data collection were conducted with the approval of the hospital and faculty institutional review board (Commission d'Ethique Biomédicale Hospitalo-Facultaire) of Université catholique de Louvain (UCLouvain), Belgium (NCT 340320084407). We thank Dr. Mariana Andrade, M.D., who provided editorial assistance. This work was supported by grants from the Actions de Recherche Concertées UCLouvain (A.R.C. grant 19/24–098) and from the Fonds de la Recherche Scientifique (F.R.S) – FNRS (CDR numbers J.0055.23 and 1M00524F). The funders had no role in study design, data collection and analysis, interpretation or writing of the manuscript. None. The patients in this manuscript have given written informed consent to participate and for publication of their case details. Dataset generated during and/or analysed during the current study is available from the corresponding author on reasonable request.

Allergic contact dermatitis and irritant contact dermatitis have different pathogenic mechanisms. It is therefore plausible that the epidermal expression of HLA-DR and the invariant chain associated with antigen processing and presentation might differ between allergic contact dermatitis and irritant contact dermatitis. We have quantified the volume of epidermal HLA-DR and invariant chain reactivity and the total epidermal volume in allergic contact dermatitis and irritant contact dermatitis using confocal laser scanning microscopy and indirect immunofluorescence on acetone-fixed 25 microns thick vertical skin sections. Eight nickel allergic patients were patch-tested with 5% nickel sulfate and 8 healthy volunteers were patch-tested with 4% sodium lauryl sulfate. Skin biopsy specimens were taken at 0, 6, 24, and 72 h after application of the patch tests. Sodium lauryl sulfate induced a statistically significant increased epidermal volume at 24 h and 72 h compared to 0 h and 6 h (p < 0.003 and p < 0.001, respectively), whereas an increase in epidermal volume in the allergic contact dermatitis group was not noted until 72 h after patch testing with nickel sulfate compared to 0, 6 h (p < 0.001) and 24 h (p < 0.004). No significant changes in the epidermal volume of HLA-DR reactivity were found at any time point within or between the two groups, nor was there any significant change in the epidermal volume of invariant chain reactivity in the allergic contact dermatitis group. In the irritant contact dermatitis group, however, the epidermal volume of invariant chain reactivity was significantly reduced from 17 +/- 8 x 10(3) microns 3 at 24 h to 9 +/- 3 x 10(3) microns 3 at 72 h (p < 0.04), which was also significantly lower than the 14 +/- 4 x 10(3) microns 3 observed in allergic contact dermatitis at 72 h (p < 0.01). Furthermore, the invariant chain expression was significantly lower than the HLA-DR reactivity in the irritant contact dermatitis group at 72 h (p < 0.001). The decrease of invariant chain reactivity at 72 h in irritant contact dermatitis might reflect an epitope-induced alteration by sodium lauryl sulfate or a down-regulated biosynthesis of the invariant chain due to variance in local cytokine production between allergic contact dermatitis and irritant contact dermatitis.

Results of evaluating health care workers with prick and patch testing

Results of Evaluating Health Care Workers With Prick and Patch Testing

Irritant and allergic contact dermatitis are common inflammatory skin diseases induced by repeated skin contact with low molecular weight chemicals, called xenobiotics or haptens. Although both diseases may have similar clinical presentations, they can be differentiated on pathophysiological grounds. Irritant contact dermatitis (ICD) is a non-specific inflammatory dermatitis brought about by activation of the innate immune system by the pro-inflammatory properties of chemicals. Allergic contact dermatitis (ACD) corresponds to a delayed-type hypersensitivity response with a skin inflammation mediated by hapten-specific T cells. Recent progress in the pathophysiology of chemical-induced skin inflammation has shown that ICD and ACD are closely associated and that the best way to prevent ACD is to develop strategies to avoid ICD. The immunological diagnosis of ICD or ACD requires investigation of the presence (ACD) or absence (ICD) of antigen-specific T cells. The detection of T cells can be performed in the skin (collected from ACD lesions or positive patch tests) and/or in the blood, particularly by using the enzyme-linked immunospot assay (ELISPOT). This method, recently developed in ACD to metals, offers a new biological tool enabling the immunobiological diagnosis of ACD.

Contact dermatitis is an inflammatory skin disease induced by direct contact of a external agent to the skin. It can be classified into two main types: Irritant contact dermatitis and Allergic contact dermatitis. Irritant contact dermatitis represents a non-specific cutaneous response to the toxic or physical effects of environmental agents, while Allergic contact dermatitis represents a specific type IV hypersensitivity reaction to specific haptens. Both types are characterized by a highly variable clinical presentation that includes erythema, papules, vesicles, bullae, scaling and erosions in acute cases, and papules, plaques, lichenification, hyperkeratosis and fisures in the chronic. Pruritus is a very common symptom most frequently associated with Allergic contact dermatitis but also frequent in Irritant contact dermatitis. Furthermore, occasionally pruritus may be the leading or only symptom that guides the clinician to suspect the diagnosis of Contact dermatitis, as it is in the case of Allergic contact dermatitis of the anogenital region or when the process occurs in the elderly. Although the mechanisms underlying the pathogenicity of the inflammatory cutaneous response in irritant and allergic contact dermatitis has been widely studied, little is known about the mechanisms leading to pruritus. This chapter summarizes the most important aspects of contact dermatitis in these specific situations as well as the last insights into the pathogenicity of pruritus in contact dermatitis.

Irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) are inflammatory skin diseases accompanied by itch and pain. Irritant contact dermatitis is caused by chemical irritants eliciting an innate immune response, whereas ACD is induced by haptens additionally activating an adaptive immune response: After initial exposure (sensitization) to the hapten, a subsequent challenge can lead to a delayed-type hypersensitivity reaction. But, the sensory and inflammatory effects of sensitization (ICD) vs challenge of ACD are insufficiently studied. Therefore, we compared itch- and pain-like behaviors and inflammatory reactions evoked in mice during the sensitization (ICD) vs challenge phase (ACD) of application of the hapten, squaric acid dibutylester (SADBE). Our aim was to compare itch- and pain-like behaviors and inflammatory reactions evoked in mice during the sensitization (ICD) vs challenge phase (ACD) of application of the hapten, squaric acid dibutylester (SADBE). Mice were sensitized on the abdomen with 1% SADBE (ACD) or vehicle treated (ICD, control). Spontaneous and stimulus-evoked itch- and pain-like behaviors were recorded in mice before and after 3 daily challenges of the cheek with 1% SADBE (ACD, ICD). Cutaneous inflammation was evaluated with clinical scoring, ultrasound imaging, skin thickness, histology, and analyses of selected biomarkers for contact dermatitis, IL-1β, TNF-α, CXCL10, and CXCR3. Allergic contact dermatitis vs ICD mice exhibited more spontaneous site-directed scratching (itch) and wiping (pain). Allergic contact dermatitis-but not ICD-mice exhibited allodynia and hyperalgesia to mechanical and heat stimuli. Inflammatory mediators IL-1β and TNF-α were upregulated in both groups as well as the chemokine receptor, CXCR3. CXCL10, a CXCR3 ligand, was upregulated only for ACD. Inflammatory responses were more pronounced in ACD than ICD. These findings provide new information for differentiating the behavioral and inflammatory reactions to hapten-induced ICD and ACD.

Baby wipes are a common cause of contact dermatitis in children, particularly on the diaper area and face. The allergens most frequently involved are fragrances and preservatives. Before 2017 and the ban on its use in Europe on non-rinse-off cosmetic products, methylisothiazolinone was a preservative frequently responsible for contact allergies to baby wipes [1]. Such reactions are less common in adults. We report a rare case of allergic contact dermatitis in an adult due to hexamidine diisethionate (CAS No. 659-40-5), an uncommon allergen found in baby wipes [2-4]. A 51-year-old man with a history of childhood eczema presented with eczematous lesions in both axillae (Figure 1A), which later spread to the face (Figure S1). Initial history did not identify any relevant exposures. Treatment with a potent topical corticosteroid led to marked improvement, allowing patch testing to be performed. Patch tests were carried out using the European baseline series, the cosmetic series, and the patient's personal products (Chemotechnique Diagnostics), according to European Society of Contact Dermatitis (ESCD) guidelines [5]. The tests were applied using IQ Ultimate chambers and read on days 2 and 3, following ICDRG criteria. Personal products such as shampoo, soap and deodorant were tested and found to be negative. Positive reactions to potassium dichromate and Compositae mix, both considered irrelevant were observed. A second, more detailed, history revealed that the patient had recently changed to a new brand of baby wipes, which he used on his axillae and face. These wipes, labelled “Pure Water,” listed only two ingredients: water and hexamidine diisethionate (Figure S2A,B). The baby wipes were intended to be used without rinsing. The concentration of hexamidine in the wipes was 0.1%. A Repeated Open Application Test (ROAT) using the wipes of the patient was positive on day 3 (Figure 1B), confirming allergic contact dermatitis (ACD) to hexamidine diisethionate [5]. The patient recalled possible prior exposure to hexamidine during treatment of a panaritium. No recurrence occurred after discontinuing the wipes. While baby wipes are a well-known cause of contact dermatitis in infants, this case of axillary and face involvement in an adult is unusual. To our knowledge, no previous cases have reported baby wipes containing hexamidine diisethionate as the cause of ACD. The diagnosis of ACD was based on the delayed positivity of the ROAT test, which is in favour of contact eczema, and on the low concentration of hexamidine in the wipes, which minimises the risk of irritation. However, irritant dermatitis cannot be formally ruled out. Interestingly, hexamidine was included in our cosmetic series used for patch testing but did not elicit a positive response, suggesting either false negativity or insufficient exposure through this method. The ROAT was instrumental in establishing the diagnosis. Hexamidine is a well-known allergen in the context of antiseptic use, particularly for wound care [4, 6, 7]. When hexamidine is used in cosmetics it is for its emollient, preservative and anti-foaming properties. Its presence in products labelled “Pure Water” is misleading for both patients and clinicians. Baby wipes labelled as “Pure Water” can contain hexamidine diisethionate, a potential allergen capable of inducing allergic contact dermatitis in adults [4]. The ROAT can be key for diagnosis when standard patch tests are inconclusive. The authors wish to thank the team of the medical information department for their invaluable statistical assistance. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Figure S1: S eczema on the patient's face. Figure S2: A and B Baby wipes used by the patient. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Practical problems in the use of patch testing in the evaluation of patients with contact dermatitis

"Slime" May Not be so Benign: A Cause of Hand Dermatitis

Differentiation of allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) is important because of different management requirements. Various non-invasive tests have been used in an attempt to improve diagnosis. In irritant dermatitis, thickening of the epidermis has been a constant finding. High-Definition Optical Coherence Tomography (HD-OCT) is a non-invasive real-time three-dimensional imaging technique with cellular resolution for which an adapted algorithmic method for pattern analysis discriminating inflammatory skin diseases has been proposed. The aim of this study was threefold. (1) To evaluate the correlation between HD-OCT features and clinical scores of allergic and irritant patch test reactions. (2) To explore the potential of HD-OCT in optimizing the visual patch test scoring. (3) To assess in vivo the cytological and 3-D micro-architectural differences in skin reaction types between doubtful positive ACD and ICD. Twenty-two volunteers were patch tested using potassium(VI)dichromate, cobalt(II)chloride, nickel(II) sulfate and palladium(II)chloride. Visual patch test scoring and HD-OCT assisted patch test scoring were performed at 48 and 96 h after patch test application according to ECDRG guidelines. Selected HD-OCT features correlated well with clinical severity scores. HD-OCT assessment improved the visual patch test scoring although not significantly. Increased epidermal thickness observed in ICD at first reading was a significant finding useful in differentiating doubtful (+?) ACD from irritant (IR) ICD reactions. In conclusion, HD-OCT might be a unique tool for in vivo non-invasive real-time three-dimensional epidermal thickness measurements helping to differentiate IR from doubtful (+?) reactions in patch testing. Selected HD-OCT features corresponded well with severity of visual scoring. These features might help to quantify the degree of inflammation in inflammatory skin conditions. HD-OCT might help in optimizing visual patch test scoring in some situations.

SnapshotDx Quiz: December 2020

Comparison of Allergic and Irritant Contact Dermatitis