Prevalence of Isotretinoin Therapy in Adolescents and Young Adults With and Without Atopic Dermatitis: A Nationwide Prescription-based Population Study

Although isotretinoin has anti-inflammatory and immunomodulatory properties, it can exacerbate atopic dermatitis. National estimates of the extent to which patients with atopic dermatitis are affected by severe acne and isotretinoin tolerability are lacking. The aim of this study is to investigate isotretinoin therapy in patients with atopic dermatitis and to compare the nationwide prevalence with individuals without atopic dermatitis. All Norwegian residents were followed for 17 years until age 20–22 years in 2020. Approximately 28% of patients with atopic dermatitis had been treated for acne, and 8% had received isotretinoin before age 23 years. In those over 17 years old, significantly more patients with atopic dermatitis were treated with isotretinoin than those without. At age 22 years, 2.21% (95% confidence interval 1.92–2.49) of patients with atopic dermatitis were treated with isotretinoin, compared with 1.55% (95% confidence interval 1.44–1.65) of those without, representing 42.8% (1.43; 95% confidence interval 1.24–1.65) higher use in patients with atopic dermatitis. Patients who received long-term treatment (probable severe atopic dermatitis) tolerated isotretinoin similarly to patients who received short-term treatment (probable mild atopic dermatitis). There was significantly higher use of topical corticosteroids during isotretinoin therapy in patients with atopic dermatitis. Conclusively, severe acne (isotretinoin therapy) was associated with atopic dermatitis at the population level in young adults. SIGNIFICANCE There are no nationwide studies on the estimated prevalence and tolerability of isotretinoin treatment in patients with atopic dermatitis (AD). Although isotretinoin has anti-inflammatory effects, isotretinoin therapy causes dryness in patients with AD who have an already impaired skin barrier. The results suggest that patients with AD, who had long-term (probable severe) disease courses, tolerated isotretinoin similarly to patients with AD with brief disease (probable mild) courses. At age 18–22 years, the frequency of severe acne was significantly higher in the population with AD than in those without. Contrary to previous assumptions, the results suggest that severe acne is a comorbidity in young adults with AD.