Physicians who treat patients with atopic dermatitis (AD) should recognize the distinct phenotypes, with lesional predilection for the hands and/or head/neck that are associated with adult-onset AD, according to the results of a recent prospective study published in the Journal of Allergy and Clinical Immunology.

Self-administered questionnaires were completed by adult patients at the eczema clinic before their encounter; all patients were also evaluated with a medical history and a skin examination by a dermatologist. A total of 356 participants ≥18 years of age were enrolled in the study; 64.6% of the patients were women, and 64.0% were white.

AD severity was assessed using the Patient-Oriented Eczema Measure, Eczema Area and Severity Index, Scoring Atopic Dermatitis, body surface area, and numeric rating scale for itch and sleeplessness. Dominant clinical phenotypes were determined via use of latent class analysis. The relationship between adult-onset AD and distinct phenotypes was assessed via multivariate logistic analysis.

Overall, 41.9% (149 of 356) of participants reported AD onset during adulthood, with 24.4% (87 of 356) of individuals reporting the onset of AD at >50 years of age. Adult-onset vs childhood-onset AD was significantly associated with birthplace outside the United States (P =.0008), but not with sex, race/ethnicity, current smoking status, or alcohol consumption (P ≥.11). Moreover, adult-onset vs childhood-onset AD was significantly associated with a decreased personal history of asthma, hay fever, and food allergy, and with a decreased family history of asthma and food allergy (P ≤.0001 for all). Adult-onset AD vs childhood-onset AD was also associated with higher rates of nummular eczema lesions.

No significant differences between adult-onset and childhood-onset AD were reported on the Eczema Area and Severity Index, Scoring Atopic Dermatitis, or Patient-Oriented Eczema Measure, or in body surface area and the numeric rating scale for itch and sleeplessness (P ≥.10). Latent class analysis identified 3 classes: high probability of flexural dermatitis and xerosis, with intermediate to high probability of head, neck, and hand dermatitis; high probability of flexural dermatitis and xerosis, but low probability of head, neck, and hand dermatitis; and low probability of flexural dermatitis, but the highest probability of all other signs and symptoms. The investigators found that adult-onset AD was significantly associated with class 1 (adjusted odds ratio, 5.54; 95% CI, 1.59-19.28) and class 3 (adjusted odds ratio, 14.03; 95% CI, 2.33-84.50) phenotypes.

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The investigators concluded that adults with AD exhibit high rates of self-reported adult-onset disease, lower prevalence of personal or family history of AD, distinct phenotypes with fewer flexural lesions and greater involvement of hands and/or head/neck, and higher rates of nummular lesions. Longitudinal studies are now underway to determine whether these distinct phenotypes are associated with varying prognoses or therapeutic responses.

Reference

Silverberg JI, Vakharia PP, Chopra R, et al. Phenotypical differences of childhood- and adult-onset atopic dermatitis [published online November 10, 2017]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2017.10.005