Pediatric allergic contact dermatitis. Part I: Clinical features and common contact allergens in children

Allergic contact dermatitis (ACD), a delayed hypersensitivity skin reaction to environmental allergens, has a prevalence that is similar in children and adults. However, diagnostic testing for ACD in pediatric populations accounts for less than one tenth of all patch tests. The relative infrequency of pediatric patch testing may be attributed to the difficulty in testing in this population, which includes a smaller surface area for patch test placement and maintaining cooperation during patch testing, especially in younger children. Diagnosis can be difficult in children because the appearance of ACD can mimic other common pediatric skin conditions, particularly atopic dermatitis and irritant contact dermatitis. Comprehensive history taking, guided by patient presentation, age group, and location of dermatitis, helps build clinical suspicion. Such clinical suspicion is one of the major reasons behind patch testing, with additional indications being recalcitrant dermatitis and dermatitis with atypical distribution. US pediatric data have shown the top allergens to be metals, fragrances, topical antibiotics, preservatives, and emollients. These trends are important to recognize to guide management and accurate diagnosis, because ACD tends to persist if the allergen is not identified and can affect patients' quality of life.

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.

iPad--increasing nickel exposure in children

We discuss allergic contact dermatitis to the iPad to highlight a potential source of nickel exposure in children.

Xbox--a source of nickel exposure in children

Macintosh laptop computers and iPhone5s were recently added to the list of potential nickel sources. The Xbox gaming controller also joins the list.

Allergic contact dermatitis in children: which factors are relevant? (review of the literature)

Allergic contact dermatitis (ACD) in children is increasing. Sensitization to contact allergens can start in early infancy. The epidermal barrier is crucial for the development of sensitization and elicitation of ACD. Factors that may influence the onset of sensitization in children are atopic dermatitis, skin barrier defects and intense or repetitive contact with allergens. Topical treatment of ACD is associated with cutaneous sensitization, although the prevalence is not high. ACD because of haptens in shoes or shin guards should be considered in cases of persistent foot eruptions or sharply defined dermatitis on the lower legs. Clinical polymorphism of contact dermatitis to clothing may cause difficulties in diagnosing textile dermatitis. Toys are another potentially source of hapten exposure in children, especially from toy-cosmetic products such as perfumes, lipstick and eye shadow. The most frequent contact allergens in children are metals, fragrances, preservatives, neomycin, rubber chemicals and more recently also colourings. It is very important to remember that ACD in young children is not rare, and should always be considered when children with recalcitrant eczema are encountered. Children should be patch-tested with a selection of allergens having the highest proportion of positive, relevant patch test reactions. The allergen exposure pattern differs between age groups and adolescents may also be exposed to occupational allergens. The purpose of this review is to alert the paediatrician and dermatologist of the frequency of ACD in young children and of the importance of performing patch tests in every case of chronic recurrent or therapy-resistant eczema in children.

Positive nickel patch tests in infants are of low clinical relevance and rarely reproducible

BACKGROUND

We have previously reported patch test reactivity to nickel sulphate in a cohort of unselected infants tested repeatedly at 3-18 months of age. A reproducible positive reaction at 12 and 18 months was selected as a sign of nickel sensitivity provided a patch test with an empty Finn chamber was negative. A reproducible positive reaction was seen in 8.6% of the infants. The objective of this study is to follow-up on infants with alleged nickel sensitivity.

METHODS

A total of 562 infants were included in the cohort and patch tested with nickel sulphate (ICDRG guidelines). The 26 children with a positive patch test reaction to nickel sulphate at 12 and 18 months were offered repeated patch tests at 3 and 6 yr.

RESULTS

Among the 21 children tested at both 12 months, 18 months and at 3 and 6 yr only 2 of 21 had reproducible nickel reactions (one clinically relevant), 13 of 21 were negative and 6 of 21 were negative at 3 or 6 yr.

CONCLUSIONS

Only 9.5% of the children had reproducible nickel sulphate reactivity, while 62% became negative. The results are noteworthy and can be interpreted in different ways: Repeated nickel patch tests did not cause patch test sensitization. The test reactions in infancy are probably of irritant or non-specific nature. Hence, nickel patch tests should only be performed in small children if there is a clinical suspicion of nickel-induced allergic contact dermatitis.