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Presentation

Pediatric Allergic Contact Dermatitis and Common Mimickers: Case-Based Review

Description

This case-based review emphasized that allergic contact dermatitis (ACD) can occur at any age, including infancy, and is a delayed T-cell mediated reaction that appears where the allergen contacts the skin. Because antihistamines are usually ineffective, management focuses on identifying exposures and using topical or systemic anti-inflammatory therapy. The speaker highlighted the importance of careful, location-based history and selective patch testing in children, using smaller customized allergen series when needed. Three true pediatric ACD cases were presented: a child with severe facial dermatitis ultimately linked to propylene glycol in topical products; a child with recurrent upper-lip/facial flares traced to fragrance exposure from a household plug-in air freshener; and a child who flared after vaccinations because of an ingredient in alcohol wipes used before injection. Three mimickers were also discussed: doxycycline-induced photosensitivity on the dorsal hands mistaken for ACD, a groin eruption from tinea corporis/tinea incognito after cat exposure that had been misread as eczema or contact dermatitis, and a dupilumab-associated head and neck dermatitis in a child with negative patch testing, where malassezia or treatment-related effects were considered. The overall message was to suspect ACD in recalcitrant or anatomically suggestive rashes, but also to broaden the differential when patch testing is negative or the pattern does not fit.

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Conclusions

Allergic contact dermatitis can occur at any age, even in infants, but patch testing must be tailored to the child’s size and exposure history.
Recalcitrant or atypically distributed eczema-like rashes in children should prompt patch testing because hidden allergens in topical products, fragrances, or medications may be the true cause.
Common relevant pediatric allergens include fragrances and excipients such as propylene glycol, and improvement can be dramatic once the offending exposure is removed.
Not all suspected contact dermatitis is actually allergic contact dermatitis, so a negative patch test or inconsistent distribution should trigger a broader dermatologic differential.
Several mimickers can look like allergic contact dermatitis, including doxycycline-induced photosensitivity, dermatophyte infection with Majocchi’s granuloma, and Dupilumab-associated head and neck dermatitis.
Careful history-taking about timing, location, outdoor exposure, household products, and treatments is essential to connect test results with true real-world relevance.
In some cases, the apparent trigger is a less obvious exposure such as alcohol prep pads, and avoiding that specific product can solve the problem.
The overall message is to suspect allergic contact dermatitis in children, but to stay willing to revise the diagnosis when the pattern, testing, or treatment response does not fit.

Yu et al. 2018
New England Journal of Medicine URL