Background-Bacterial infection with Staphylococcus aureus is a known trigger for worsening of atopic dermatitis (AD); the exact mechanisms by which bacterial infection worsens dermatitis are unknown.

Finally, we measured levels of LTA that were adequate to stimulate PAF-R in vitro on the skin of subjects with infected atopic dermatitis. Based on these studies, we propose that LTA exerts immunomodulatory effects via the PAF-R through production of the Th2 cytokine IL-10. These findings show a novel mechanism by which staphylococcal infections can inhibit Th1 reactions and thus worsen Th2 skin diseases, such as atopic dermatitis.

IMPORTANCE Atopic dermatitis (AD) and allergic contact dermatitis (ACD) have a dynamic relationship not yet fully understood. Investigation has been limited thus far by a paucity of data on the overlap of these disorders in pediatric patients.OBJECTIVE To use data from the Pediatric Contact Dermatitis Registry to elucidate the associations and sensitizations among patients with concomitant AD and ACD. DESIGN, SETTING, AND PARTICIPANTSThis retrospective case review examined 1142 patch test cases of children younger than 18 years, who were registered between January 1, 2015, and December 31, 2015, by 84 health care providers (physicians, nurse practitioners, physician assistants) from across the United States. Data were gathered electronically from multidisciplinary providers within outpatient clinics throughout the United States on pediatric patients (ages 0-18 years).EXPOSURES All participants were patch-tested to assess sensitizations to various allergens; history of AD was noted by the patch-testing providers. MAIN OUTCOMES AND MEASURESPrimary outcomes were sensitization rates to various patch-tested allergens.RESULTS A total of 1142 patients were evaluated: 189 boys (34.2%) and 363 girls (65.8%) in the AD group and 198 boys (36.1%) and 350 girls (63.9%) in the non-AD group (data on gender identification were missing for 17 patients). Compared with those without AD, patch-tested patients with AD were 1.3 years younger (10.5 vs 11.8 years; P < .001) and had longer history of dermatitis (3.5 vs 1.8 years; P < .001). Patch-tested patients designated as Asian or African American were more likely to have concurrent AD (odds ratio [OR], 1.92; 95% CI, 1.20-3.10; P = .008; and OR, 4.09; 95% CI, 2.70-6.20; P <.001, respectively). Patients with AD with generalized distribution were the most likely to be patch tested (OR, 4.68; 95% CI, 3.50-6.30; P < .001). Patients with AD had different reaction profiles than those without AD, with increased frequency of reactions to cocamidopropyl betaine, wool alcohol, lanolin, tixocortol pivalate, and parthenolide. Patients with AD were also noted to have lower frequency of reaction to methylisothiazolinone, cobalt, and potassium dichromate.CONCLUSIONS AND RELEVANCE Children with AD showed significant reaction patterns to allergens notable for their use in skin care preparations. This study adds to the current understanding of AD in ACD, and the continued need to investigate the interplay between these disease processes to optimize care for pediatric patients with these conditions.

This US database provides multidisciplinary information on pediatric ACD, rates of PPT, and relevant RPPT reactions, validating the high rates of pediatric ACD previously reported in the literature. The registry database is the largest comprehensive collection of US-only pediatric patch test cases on which future research can be built. Continued collaboration between patients, health care providers, manufacturers, and policy makers is needed to decrease the most common allergens in pediatric consumer products.