Israel Medical Association Journal

Background: The association between new-onset atopic dermatitis (AD) and the coronavirus disease 2019 (COVID-19) pandemic was scarcely documented in the literature.

Objectives: To evaluate the incidence of AD in a large nation-wide cohort over 6 years, focusing on changes in incidence following the onset of the COVID-19 pandemic.

Methods: This retrospective cohort study included all members of the largest HMO in Israel (n=4.8 million) from 2017 to 2022. Patients with newly diagnosed AD were identified using the ICD-10 code for AD (L20). Incidence rates were calculated as the number of new diagnoses per 1000 person-years. The pre-COVID period was 1/2017 to 1/2020, and post-COVID 2/2020 to 12/2022. Age-adjusted incidence rates were calculated based on the World Health Organization's standard population.

Results: The overall crude incidence of AD across the study period was 3.38/1000 person-years (PYs). From 2017 to 2022, there was a 36.97% increase in the crude incidence and a 40.44% increase in the age-adjusted incidence, with a mean annual incidence change of +6.5% and +7.1%, respectively. Both crude and adjusted annual incidence increases were significant (P < 0.001, R² = 0.98; P < 0.001, R² = 0.99, respectively). The incidence of AD at the follow-up before the COVID-19 pandemic was 3.07/1000 PYs, and after was 3.71/1000 PYs.

Conclusions: We observed a significant and nearly consistent annual increase in AD incidence from 2017 to 2022, across various sex and age groups. Further research is needed to explore the impact of the COVID-19 pandemic on rising trends in AD incidence.

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease involving apocrine gland-bearing regions. There is an under-representation of non-Caucasians in epidemiologic studies of HS. The characteristics of HS in Israeli Arabs have not yet been studied.

Objectives: To investigate the demographic and clinical profile of HS in the Israeli Arab population.

Methods: A retrospective analysis was conducted in two cohorts of patients with HS in Israel. The patients were derived from the database of a large health management organization (n=4191, 639 Arabs; population-based) and a major tertiary medical center (n=372, 49 Arabs). Demographic and clinical data were compared between ethnic groups.

Results: The prevalence of HS in Israeli Arabs was found to be 0.5%, fivefold higher than in Jews. Arab patients were younger (35.3 vs. 40.5 years, P < 0.001) and mostly male (52% vs. 35.7%, p < 0.001), with lower rates of co-morbidities, including smoking (40.8% vs. 55.7%, p < 0.001), hyperlipidemia, and depression as well as a higher rate of dissecting cellulitis (10.2% vs. 1.9%, p = 0.008). HS was more severe in Arabs, but of shorter duration, with mainly axillary involvement (79.6% vs. 57.9%, p = 0.004). Treatment with hormones was more common in Jews, and with biologic agents in Arabs.

Conclusions: The findings suggest a different phenotype of HS in Arabs, warranting further study.