PA41 Treating severe nodulocystic acne with isotretinoin in children with cystic fibrosis

Abstract We explore the therapeutic challenges and considerations related to isotretinoin for severe acne in children with cystic fibrosis (CF). We present a case to highlight the interplay between vitamin A deficiency and supplementation, potential for liver dysfunction, and potential for acneiform eruptions with CFTR modulators, in CF. We reviewed the chart of a child prescribed isotretinoin for severe acne to describe his clinical course. We also performed a literature review to assess all previously reported cases of acne treated with isotretinoin in children with CF. A 16-year-old boy presented with severe nodulocystic acne. He had a history of CF, CF-related liver disease requiring liver transplantation, and CF-related diabetes mellitus. Treatment with isotretinoin was initiated at a low dose of 10 mg (0.15 mg kg−1) and cautiously increased to a maximum of 60 mg (0.9 mg kg−1) over 10 months. Complete clearance was achieved with minimal residual scarring. Liver function and triglycerides were monitored every 2 months. Vitamin A supplementation was held (and vitamin D, E, K supplementation continued), as recommended by the isotretinoin package insert and our paediatric gastroenterology and respiratory colleagues. Serum vitamin A level was low (1.0 μmol L−1, normal range 1.4–3.84) at the end of the treatment course. Isotretinoin presents therapeutic challenges in CF due to altered physiology, including malabsorption of vitamin A requiring supplementation with fat-soluble vitamins, potential hepatic and pancreatic dysfunction, and xerosis. Reduced dosing and extended treatment durations may be required in this cohort. Increased frequency of monitoring of liver function, triglyceride levels and vitamin A levels should be considered in these patients. CFTR modulators, now commonly used in CF, can increase sebum production but can also improve absorption of fat-soluble vitamins. Alternative acne treatments, such as antibiotics, carry the risk of antibiotic resistance, a significant challenge in this population. This case highlights the importance of individualized approaches to isotretinoin treatment and multidisciplinary collaboration.