Contact allergens in African countries: A review of published patch test studies.

Only few studies on contact allergy in African countries have been published. The aim of the present study was to provide an overview of the most common contact allergens identified by the use of patch tests in African countries based on a review of the existing literature. A total of twenty-four publications from eight African countries were initially identified by search in PubMed. The abstracts and method sections were screened, and 15 studies in which patch tests were actually used to identify the allergen causing the allergic contact dermatitis (ACD) were finally selected. Nickel, cobalt, chromium, fragrance mix and p-tert-butylphenol-formaldehyde resin were the dominating contact allergens responsible for 40%-90% of the positive patch test reactions. This study indicates that a targeted effort directed towards prevention, avoidance and regulation of reliably identified contact allergens could reduce the disease burden of ACD considerable in some African countries.

Contact allergy to SIDAPA baseline series allergens in patients with eyelid dermatitis: An Italian multicentre study.

BACKGROUND: Eyelid dermatitis is a frequent reason of dermatological consultation. Its aetiology is not univocal, being contact dermatitis, both allergic and irritant, the most frequent. The primary sources of allergen exposure include cosmetics, metals, and topical medications, from direct, indirect, or airborne contact. OBJECTIVES: To define the frequency of positive patch test reactions to SIDAPA baseline series allergens, to document positive allergens, and to precise the final diagnosis in patients with eyelid involvement. METHODS: A total of 8557 consecutive patients from 12 Italian Dermatology Clinics underwent patch testing with SIDAPA baseline series in 2018 and 2019. Patients were divided into two groups: (i) with eyelid involvement with or without other involved sites (E-Group) and (ii) without eyelid involvement (NE-Group). The final diagnosis and the frequency of positive relevant patch test reactions were evaluated. RESULTS: E-Group consisted of 688 patients (females 78.6%, mean age 45.3 years), 8.0% of 8557 consecutively patch-tested patients. The final diagnosis in E-Group was ADC in 42.4%, ICD in 34.2%, and AD in 30.5%. The highest reaction rates were elicited by nickel sulphate and methylchloroisothiazolinone/methylisothiazolinone in both E-Group and NE-Group, even if these allergens were significantly more frequently positive in NE-Group patients than in E-Group ones. Positive patch test reactions to fragrance Mix II, dimethylaminopropylamine, and sorbitan sesquiolate were significantly more frequent in E-Group patients than in NE-Group ones. CONCLUSIONS: Eyelid dermatitis is a frequent dermatological complaint. Allergic contact dermatitis is the most frequent diagnosis commonly caused by nickel sulphate, isothiazolinones, and fragrances. The surfactants dimethylaminopropylamine and sorbitan sesquioleate are emerging causes of eyelid allergic contact dermatitis.

Perceptions of skincare ingredients and product labels in pediatric eczema care.

Educating pediatric eczema patients and caregivers on appropriate product selection and avoidance of common irritants or allergens is a crucial aspect of eczema management. This study surveyed 80 pediatric caregivers in an academic pediatric dermatology clinic to assess influential factors in caregivers' selection of pediatric eczema-care products and identify ways to improve patient counseling on appropriate product selection and avoidance of common irritants or allergens. Caregivers frequently reported positive perceptions of commonly recommended ingredients for eczema but had inconsistent perceptions of fragrant plant oils and extracts, regardless of previous counseling on fragrance avoidance. These findings demonstrate uncertainty and misperceptions perpetuated by product labeling and a need for improved counseling strategies for avoiding fragrance and excessive product costs.

Sensitizing fragrances in absorbent hygiene products.

BACKGROUND: Allergenic fragrances are present in a wide range of products but they are not regulated in all industries to the same extent. In Europe, absorbent hygiene products (AHPs) are only covered by the general product safety directive and therefore fragrances can be used freely, whereas in cosmetics and toys the use of these ingredients is regulated. METHOD: An analytical method was developed to evaluate the presence of 24 sensitizing fragrances in AHPs. This method allows simultaneous identification and quantification and was validated using the total error approach with an acceptance value of ±15%. RESULTS: The validated method was applied to evaluate 10 scented AHPs consisting of four tampons, three panty liners, and three sanitary pads. Eight allergenic fragrances were identified in these products and five products contained at least one allergen above 10 µg/g. CONCLUSION: The presence of these allergens is not communicated to the consumer. This is, however, a strict requirement in other industries (eg, cosmetics, toys) to ensure adequate consumer protection. Knowing that the exposed area is more susceptible to allergens and irritants, the presence of these allergens should be disclosed.

Harnessing co-operative immune augmentation by contact allergens to enhance the efficacy of viral vaccines.

Although the development of successful vaccines against coronaviruses may be achieved, for some individuals the immune response that they stimulate may prove to be insufficient for effective host defence. The principle that a relatively strong contact allergen will have an enhancing effect on sensitization compared with a less potent contact allergen if they are co-administered, may not, at first, appear relevant to this issue. However, this augmentation effect is thought to be due to the sharing of common or complementary pathways. Here, we briefly consider aspects of the shared and complementary pathways between skin sensitization induced by exposure to a contact allergen and the immune response to viruses, with particular reference to COVID-19. The relationship leads us to explore whether this principle, which we name here as "co-operative immune augmentation" may be extended to include viral vaccination. We consider evidence that even relatively weak contact allergens, used in vaccines for other purposes, can show enhanced sensitization, which is in keeping with a co-operative augmentation principle. Finally, we consider how the potent contact allergen diphenylcyclopropenone could be employed safely as an enhancer of vaccine responses.

Atopic Dermatitis: Identification and Management of Complicating Factors.

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease, associated with impaired skin barrier function and an atopic background. Various complicating factors, such as irritants, aeroallergens, food, microbial organisms, contact allergens, sweat, and scratching can induce the development of AD symptoms. Irritants, including soap/shampoo and clothes, can cause itching and eczematous lesions. In addition, young children with AD tend to become sensitized to eggs, milk, or peanuts, while older children and adults more often become sensitized to environmental allergens, such as house dust mites (HDM), animal dander, or pollen. Serum-specific IgE levels and skin prick test reactions to food tend to show high negative predictive values and low specificity and positive predictive values for diagnosing food allergy. On the other hand, AD adult patients tend to have severe skin symptoms and exhibit high HDM-specific IgE levels. Microbial organisms, e.g., Staphylococcus aureus and Malassezia furfur, might contribute to the pathogenetic mechanisms of AD. While sweat plays a major role in maintaining skin homeostasis, it can become an aggravating factor in patients with AD. Furthermore, scratching often exacerbates eczematous lesions. Several patient-specific complicating factors are seen in most cases. The identification and management of complicating factors are important for controlling AD.

[Prevalence of contact sensitization in the general population and in patch tested patients]. / Prävalenz der Kontaktsensibilisierung in der Allgemeinbevölkerung und in Klinikpopulationen.

BACKGROUND: Contact sensitization is a common condition. The spectrum of the most important allergens may change over the course of time owing to changes in exposure. Using the so-called baseline series, a collection of the most important and frequent allergens, both population-related and clinical epidemiological studies have been performed. OBJECTIVES: Basic epidemiological concepts and special aspects regarding the epidemiology of contact allergies are presented. MATERIALS AND METHODS: A concise adaptation of textbook knowledge and a selective literature search were performed. RESULTS: On the population level, about 25% of people are sensitized to at least one substance included in the baseline series, by far most often to nickel. In view of a prevalence of around 4%, fragrances are important contact allergens, too, along with preservatives. Among patients patch tested for suspected allergic contact dermatitis, the ranking of the most important allergen groups is similar, but the prevalences are (much) higher. CONCLUSIONS: Short-term changes in exposure and subsequently in the spectrum of major contact allergens can best be illustrated by clinical surveillance based on routinely collected data and, if needed, preventive measures can be initiated. In addition to time trend analyses, subgroup analyses may offer important clues regarding the identification of sensitizing and eliciting exposures, respectively.

Chemical-induced contact allergy: from mechanistic understanding to risk prevention.

Chemical allergens are small molecules able to form a sensitizing complex once they bound to proteins. One of the most frequent manifestations of chemical allergy is contact hypersensitivity, which can have serious impact on quality of life. Allergic contact dermatitis is a predominantly CD8 + T cell-mediated immune disease, resulting in erythema and eczema. Chemical allergy is of considerable importance to the toxicologist, who has the responsibility of identifying and characterizing the allergenic potential of chemicals, and estimating the risk they pose to human health. This review aimed at exploring the phenomena of chemical-induced contact allergy starting from a mechanistic understanding, immunoregulatory mechanisms, passing through the potency of contract allergen until the hazard identification, pointing out the in vitro models for assessing contact allergen-induced cell activation and the risk prevention.

Inflamed skin predisposes to sensitization to less potent allergens.

BACKGROUND: Irritant dermatitis, caused by genetic barrier dysfunction in atopic dermatitis or wet work in hand dermatitis, induces innate immune response that might predispose to allergic contact sensitization to less potent sensitizers. OBJECTIVES: We sought to determine if positive patch test results to less potent allergens are more prevalent in patients with a history of childhood flexural dermatitis or current wet work. METHODS: We examined our database of patients presenting to a contact dermatitis clinic tested to potential contact allergens as indicated by their history. Allergens from our most recent standard were studied if they could be classified as weak, moderate, or strong sensitizers based on published data from the local lymph node assay. Patients were stratified by a history of childhood-onset flexural dermatitis as a proxy for atopic dermatitis and by occupation. RESULTS: History of childhood-onset dermatitis predisposed to contact allergy to weak sensitizers and wet work to medium-potency sensitizers. Neither predisposed to contact allergy from strong sensitizers. LIMITATIONS: Association cannot prove causation. CONCLUSIONS: We conclude that strong sensitizers do not require wet work or atopy to cause sensitization. Barrier defects associated with childhood eczema and wet work may promote sensitization to weak antigens.

Patch testing in Iranian children with allergic contact dermatitis.

BACKGROUND: Allergic contact dermatitis is a common disorder in adults and children alike and appears to be on the increase. The purpose of this study was to determine the sensitization trends in Iranian children with contact dermatitis. METHODS: The result of 109 patch tests performed using the 24 allergens of the European Standard Series in patients below 18 years old from September 2007 to March 2009 were recorded and analyzed. The tests were evaluated at 48 and 72 h after performing. RESULTS: The study population consisted of 72 (66.1 %) females and 37 (33.9 %) males. Hands were the most commonly affected anatomic site. In the final evaluation of the tests on day three, 51 (46.8 %) individuals showed a positive reaction to at least one allergen. Females were significantly more likely to show a positive response to at least one allergen (p-value = 0.031, odds ratio: 2.46). The most common allergens were nickel sulfate, cobalt, methylisothiazolinone, and colophony with 21 (19.3 %), 11 (10.1 %), 7 (6.4 %), and 6 (5.5 %) positive reactions, respectively. Contact allergy to nickel sulfate was more common in females than males (23.6 % vs. 10.8 %). There was no statistically significant relationship between personal or family history of atopy and a positive reaction to patch testing. The clinical and practical relevance were assessed for nickel and cobalt with a clinical current relevance in 11 (52.3 %) and 4 (36.4 %), respectively. CONCLUSIONS: Nickel sulfate, cobalt, methylisothiazolinone, and colophony are the most common allergens responsible for induction of allergic contact dermatitis in Iranian children and adolescents. Females tended to show more positive reactions to allergens.

Contact sensitizers in commercial hair dye products sold in Thailand.

BACKGROUND: Hair dyes are known to contain potent contact allergens for which sensitization rates have increased over the last decade. OBJECTIVE: To examine the type and frequency of potent contact sensitizers labelled on hair dyes sold in metropolitan Bangkok, Thailand. METHODS: During the 2013-2014 study period, labelled ingredient information from home use and professional hair dye products was collected. RESULTS: Two hundred and fifty-two hair dye products were evaluated. One hundred and forty-nine products from 48 brands were domestically produced in Thailand, and 103 products were from 23 multinational brands produced in countries other than Thailand. Two hundred and fourteen of 252 (84.9%) hair dye products were found to contain strong skin sensitizers, with 118 (46.8%) being found in domestically produced products, and 96 (38.1%) being found in multinational brand products. Thirty-eight hair dye products (15.1%) were free of potent skin sensitizers. The number of domestically produced products (31, 20.8%) that were free of potent skin sensitizers was significantly higher (p = 0.002) than the number of multinational brand products (7, 6.8%). CONCLUSIONS: p-Phenylenediamine was the most prevalent potent sensitizer found among domestically produced hair dyes available on the market. Our findings indicate regional differences in hair dye allergen exposure.

EAACI position paper for practical patch testing in allergic contact dermatitis in children.

INTRODUCTION: Allergic contact dermatitis (ACD) in children appears to be on the increase, and contact sensitization may already begin in infancy. The diagnosis of contact dermatitis requires a careful evaluation of a patient's clinical history, physical examination, and skin testing. Patch testing is the gold standard diagnostic test. METHODS: Based on consensus, the EAACI Task Force on Allergic Contact Dermatitis in Children produced this document to provide details on clinical aspects, the standardization of patch test methodology, and suggestions for future research in the field. RESULTS: We provide a baseline list of test allergens to be tested in children with suspected ACD. Additional tests should be performed only on specific indications.

Strip patch testing does not affect reaction profiles of standard allergens.

BACKGROUND: It has been hypothesized that positive reactions in the strip patch test are irritant rather than allergic. OBJECTIVE: To study reaction profiles of the baseline series patch test substances applied routinely on tape-stripped skin according to the reaction index (RI) and the positivity ratio (PR). PATIENTS AND METHODS: One thousand two hundred and twenty-eight consecutive patients were routinely strip patch tested with the baseline series between January 2011 and June 2013 (intervention group). On the basis of test reactions at D3/D4, the RI, and the PR, 25 standard allergens were analysed, and the results were compared with those obtained in 1161 patients patch tested conventionally from July 2008 to December 2010 (historical control group). RESULTS: Nickel sulfate, fragrance mix I, cobalt chloride, Myroxylon pereirae (balsam of Peru) and colophonium showed the highest frequencies of positive reactions in both groups, without any significant differences. Of 25 patch test substances of the baseline series, 18 showed good reaction profiles in the intervention group, and 16 in the historical control group. CONCLUSIONS: Reaction profiles of baseline series patch test substances remained largely unaffected by tape stripping the skin prior to patch testing. Thus, if conventional patch test results are presumed to be false-negative, performance of the strip patch test can be recommended independently of the standard allergen.

[Contact allergies in the elderly]. / Kontaktallergien bei Senioren.

The percentage of seniors (> 65 years of age) in the general population continues to rise. Their sensitization profile may be influenced by lifelong work-related and nonwork-related exposures and comorbidities requiring local or systemic treatment. Recent analysis of the IVDK (Information Network of Departments of Dermatology) cohort concerning the most frequently recognized contact allergens in the age group above 65 (2009-2013: N = 14,841) revealed significant differences compared to the age group up to 65 years of age. The top 10 contact allergens recognized in individuals older than 65 years were the following: fragrance mix, Myroxylon pereirae (Balsam of Peru), nickel (II) sulfate, fragrance mix II, colophony, propolis, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), lanolin alcohol, Amerchol L 101, tert-butylhydroquinone. Sensitization to nickel was significantly less frequent, while sensitizations to fragrance mix and Balsam of Peru were significantly more frequent than in the age group up to 65 years of age. The percentage of patients with leg dermatitis was 25.9 % in the age group above 65 (versus 5.8 % in the age group up to 65 years of age). The analysis of the subgroup over 65 years of age with and without ulcer/stasis dermatitis/chronic venous insufficiency displayed remarkable differences in sensitization frequencies against ingredients of topical ointments (lanolin alcohol, Amerchol L 101, and tert-butylhydroquinone). If these comorbidities exist, patch testing of the topical ointment series parallel to the standard series is worthwhile.

[Diagnostic workup of fragrance allergy]. / Diagnostik der Duftstoffallergie.

The diagnostic workup of contact allergy to fragrances must not be limited to patch testing with the two well-established fragrance mixes. False-positive reactions to these mixes occur in up to 50 % of the patch tested patients. For the diagnostic work-up of positive reactions, and in cases of suspected fragrance allergy, patch testing with the single mix components and additional fragrances is mandatory. Frequently sensitizing fragrance materials are the 14 components of the two fragrance mixes and tree moss (Evernia furfuracea), ylang ylang oil (I + II; Cananga odorata), lemongrass oil (Cymbopogon schoenanthus), sandalwood oil (Santalum album), jasmine absolute (Jasminum spp.), and, less frequently, clove oil (Eugenia caryophyllus), cedarwood oil (Cedrus atlantica/deodara, Juniperus virginiana), Neroli oil (Citrus aurantium amara flower oil), salicylaldehyde, narcissus absolute (Narcissus spp.), and patchouli oil (Pogostemon cablin).

Contact Allergy in the Elderly: A Study of 600 Patients.

The proportion of elderly in the general population is increasing. Ageing of the skin and immune system can modify the features of contact hypersensitivity (CH). The number of epidemiological studies according to the age-related features of CH is very limited. We aimed to analyse the clinical characteristics of CH in an elderly patient population. A total of 600 patients (patient age > 60 years old) were patch tested with the European Environmental Baseline Series (EEBS) and 440 of them with the Complementary Fragrance Series (CFS) at the same time according to the actual international methodological standards in the Allergy Outpatient Unit of Department of Dermatology, Venereology and Dermato-Oncology of Semmelweis University between 2015−2019. Out of 600 tested patients, 54.8% had at least one allergen positivity. Female predominance was observed (78.7%). The most common diagnosis was contact dermatitis (63.7%), followed by psoriasis (6.2%). Most of the cases (58.0%) were found in the age group of 60−69. The five most common contact allergens were benzoic acid, methylisothiazolinone (MI), wood tar, nickel, and balsam of Peru. Allergic skin symptoms are present in all ages and also in the elderly. According to our data, the most common contact allergens are preservatives, followed by balsam of Peru among men and nickel among women. In case of contact dermatitis, stasis dermatitis, rosacea, and atopic dermatitis are worth patch testing to verify CH even in those above 60 years old.