Atopic dermatitis (AD) and psoriasis (Pso) are highly prevalent chronic inflammatory skin diseases. They share similarities regarding severity and impact on quality of life but display differences regarding risk factors, comorbidities, and pathogenesis.

This study sought to assess the prevalence of AD and Pso among the French population, along with associated comorbidities, and to compare these data with those of the age- and gender-adjusted French population with neither AD nor Pso.

The survey was conducted by a polling institute between September 1 and November 30, 2016, with proportional quota sampling being applied to render the study population representative of the French population. In all, 20 012 individuals were selected from among 900,000 internet users aged≥15years.

Overall, 20,012 adults (48.8% men; 51.2% women) completed a digital questionnaire. The prevalence of AD was 4.65% [95% confidence interval (CI) 4.36%–4.94%] and that of Pso was 4.42% [95% CI: 4.14%–4.71%]. More AD patients presented≥1 comorbidity compared to subjects without AD (57.04% vs. 49.2%, P<0.0001) and more Pso patients presented≥1 comorbidity compared to subjects without Pso (60.68% vs. 49.05%, P<0.0001). After adjustment for gender and age, hypertension and dyslipidemia, a greater prevalence of osteoarticular, respiratory and psychiatric diseases was noted in both AD and Pso patients, whereas increased prevalence of obesity was seen only in Pso patients. The prevalence of components of metabolic syndrome was higher among Pso than AD patients.

Further studies are required to consolidate these findings, to better characterize the entire spectrum of AD and Pso comorbidities, and to better identify determinants and risk factors, along with targeted therapies.