Patch testing in Israeli children with suspected allergic contact dermatitis: A retrospective study and literature review

Background/objectives

Childhood allergic contact dermatitis is recognized as a significant clinical problem. The objective was to evaluate the rate of positive patch tests in Israeli children with clinically suspected allergic contact dermatitis, identify possible sex and age differences, compare results with those in Israeli adults, and review pediatric studies in the literature.

Methods

The study sample included 343 children and adolescents (197 female, 146 male; 1‐18 years of age, mean age 11.8 years) with clinically suspected allergic contact dermatitis who underwent patch testing with a standard pediatric series of 23 allergens at a tertiary medical center from 1999 to 2012. Data on clinical characteristics and test results were collected retrospectively from the medical files.

Results

Ninety‐eight subjects (28.6%) (75 girls [38.1%], 23 boys [15.8%]) had at least one positive reaction. The most frequent reactions were to nickel sulfate, followed by potassium dichromate and cobalt chloride. Nickel sulfate sensitivity was more common in girls, especially those younger than 3 years and older than 12 years. The prevalence of contact sensitization was similar in subjects with and without atopic dermatitis (50% and 51%, respectively).

Conclusion

Nickel is the most common allergen in Israeli children, especially girls. Patch testing should be performed in children with clinically suspected allergic contact dermatitis regardless of atopic background.     

Contact hypersensitivity and allergic contact dermatitis among school children and teenagers with eczema

Background:  Patch testing is an essential procedure in the investigation of eczema in children.
Objectives:  To analyse the frequency of contact hypersensitivity and allergic contact dermatitis among Polish children with eczema.
Patients/methods:  During an allergy screening programme involving 9320 children aged 7 and 16 years, 12.6% reported symptoms of chronic/recurrent eczema. From this group, a representative sample of 229 eczema children underwent patch testing: 96 children aged 7 years and 133 teenagers aged 16 years. Patch testing was with 10 allergens: methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), nickel sulfate, mercury ammonium chloride, thimerosal, cobalt chloride, potassium dichromate, lanolin, fragrance mix I, Myroxylon pereirae (balsam of Peru), and colophonium.
Results:  49.4% tested children were found patch test (PT) positive. 43.8% of 7 year olds with eczema were PT positive, with sensitization to nickel sulfate (30.2%), thimerosal (10.4%), cobalt chloride (8.3%), fragrance mix I (7.3%), MCI/MI (6.3%), potassium dichromate (6.3%), M.   pereirae (3.1%), mercury ammonium chloride (2.3%), and colophonium (1.0%). 52.6% teenagers were PT positive, with sensitization to nickel sulfate (23.3%), thimerosal (27.8%), cobalt chloride (10.5%), potassium dichromate (6.0%), mercury ammonium chloride (2.3%), M. pereirae (1.5%), and MCI/MI (0.8%). The final diagnosis of allergic contact dermatitis was confirmed in 36% of 7 year olds and 26% of 16 year olds.
Conclusions:  Every second child with eczema is PT positive, whereas every third child is finally diagnosed with allergic contact dermatitis.     

Allergens responsible for allergic contact dermatitis among children: a systematic review and meta-analysis

Background. Multiple studies have evaluated diverse allergens in paediatric populations. Consensus is still lacking on which allergens are most commonly implicated in allergic contact dermatitis. Objectives. To evaluate the proportion of positive reactions for allergens tested in children and to identify allergens with positive reactions in at least 1% of them. Methods. This was a systematic review of studies in PubMed (1966–2010) investigating allergens in at least 100 enrolled children. Proportions of positive reactions for each allergen were combined with random effects models across studies. Results. We included 49 studies with available data on 170 allergens. Each study tested a median of two allergens. Among the 94 allergens evaluated by at least two studies, 58 had estimates of positive reactions of at least 1% by random effects calculations, and for 21 of them the 95% confidence interval ensured that the proportion of positive reactions was at least 1%. The top five allergens tested by at least two studies included nickel sulfate, ammonium persulfate, gold sodium thiosulfate, thimerosal, and toluene‐2,5‐diamine (p‐toluenediamine). For most allergens, the proportion of positive reactions was higher in studies published after 1995 than in earlier studies (p = 0.0065). Conclusions. This meta‐analysis offers guidance on which allergens are most prevalent in the paediatric population and should have priority for inclusion in standardized allergen series.     

Influence of skin peeling procedure in allergic contact dermatitis

Background:  The prevalence of allergic contact dermatitis in patients who have previously undergone skin peeling has been rarely studied.
Objectives:  We compared the frequency of positive patch test (PT) reactions in a patient group with a history of peeling, to that of a control group with no history of peeling.
Patients/Methods:  The Korean standard series and cosmetic series were performed on a total of 262 patients. 62 patients had previously undergone peeling and 200 patients did not.
Results:  The frequency of positive PT reactions on Korean standard series was significantly higher in the peeling group compared with that of the control group ( P  < 0.05, chi-square test). However, the most commonly identified allergens were mostly cosmetic-unrelated allergens. The frequency of positive PT reactions on cosmetic series in the peeling group was higher than that of the control group, but lacked statistical significance. The frequency (%) of positive PT reactions on cosmetic series in the high-frequency peel group was higher than that of the low-frequency group, but lacked statistical significance.
Conclusion:  It appears peeling may not generally affect the development of contact sensitization. Further work is required focusing on the large-scale prospective studies by performing a PT before and after peeling.     

Contact allergy to aeroallergens in children with atopic dermatitis: comparison with allergic contact dermatitis

Immediate and delayed cutaneous hypersensitivity are believed to be implicated in the physiopathology atopic dermatitis (AD). The purpose of this study was to evaluate Type I and Type IV allergy to aeroallergens in children with AD. 59 children (mean age 5.2 years), presenting with AD according to Hanifin and Rajka's criteria, were skin tested (patch and corresponding prick tests) with common environmental aeroallergens and a restricted panel of the European standard series over a 1-year period. History and clinical data were carefully recorded using a standardized evaluation sheet: total and specific IgE serum levels were evaluated 17 of 59 patients (28.8%) had at least 1 positive patch test, 32 of 59 patients (54.2%) had at least 1 positive prick test. Corresponding patch and prick tests were observed in 8 out of 17 patients. 5 children with positive patch tests had negative prick tests. Irritant pustular reactions (2/59, i.e. 3%), "angry back" reactions (6/59, i.e. 10%) and doubtful reactions (3/59, i.e. 5%) were excluded from the positive group. Positive patch tests observed included, in decreasing order: D. pteronyssinus and D. farinæ (26.8%) garden trees (12.2%), plantain (9.8%), timothy grass, mugwort and damp area trees (4.9% each), and orchard grass (2.44%). 6 children with positive aeroallergen patch tests and 11 children with negative aeroallergen patch tests had at least 1 positive patch test to standard allergens. All children with an irritant reaction to aeroallergens had no reaction to standard patch tests. The relevance of aeroallergens in upgrading the severity of AD lesions has still to be explored by challenge studies and by long-term follow-up.     

Contact dermatitis in children

168 children, 14 years of age or younger, were patch tested with the Standard Series of the International Contact Dermatitis Research Group (ICDRG) over a 5-year period, 77 of the children had 1 or more positive reactions: relevant test results were found in 80% of them.
8 boys and 24 girls were allergic to nickle, which proved to be the most common allergen: 5 boys and 6 girls reacted to chromate, and 5 boys and 4 girls reacted to one or more of the rubber chemicals.     

Contact dermatitis in children

125 children under the age of 12 years were patch tested over a period of 7 years. 60 (48%) of the children had 1 or more positive (+ve) reactions, of which 92% (55/60) were considered relevant. The most common allergens were metals (35 + ves), fragrances (24 + ves) and rubber compounds (11 + ves). 40 of the children were also tested for contact urticaria against food additives and fragrances, of whom 20 were positive (benzoic acid 14, cinnamaldehyde 12).     

Intradermal testing in the diagnosis of allergic contact dermatitis

Contact hypersensitivity may be diagnosed with patch testing or intradermal testing. Although these methods have been used earlier in parallel, patch testing has gradually become the only method in routine diagnosis of contact allergy. Recent findings in corticosteroid contact hypersensitivity have shown that patch testing is not always an optimal method, especially when poor penetrants are used. Therefore, a reappraisal of intradermal testing is presented, based on the literature. Studies employing both patch and intradermal testing are reviewed and the advantages and disadvantages of intradermal tests as compared to patch tests in contact allergy diagnostics are discussed. We find that it might be worthwile to evaluate whether contact allergy to compounds other than corticosteroids may be easier to detect with intradermal than patch test.     

Contact dermatitis in children

272 children up to the age of 14 years were patch tested during a 10-year period (1982–1991). 101 children (37.1%) gave positive reactions to 1 or more allergens. Of these, 54.4% (57/101), were considered relevant. The main allergens were, in order of frequency: nickel, rubber compounds, mercuric chloride, cobalt salts, thimerosal, benzoyl peroxide and fragrance mix.