Isotretinoin Skeletal Effects — SCE Dermatology MCQ

Correct answer: C — Isotretinoin can cause premature disc degeneration and skeletal hyperostosis (DISH-like changes) with long-term or high-dose use

The correct answer is C, isotretinoin can cause premature disc degeneration and skeletal hyperostosis (DISH-like changes) with long-term or high-dose use. Retinoids alter osteoblast and osteoclast activity and disrupt bone and connective tissue turnover, producing radiological changes that mimic diffuse idiopathic skeletal hyperostosis, including hyperostosis, ligament and tendon calcification, and accelerated disc degeneration with Schmorl node formation. These changes were first described with the high cumulative doses used historically for keratinisation disorders such as ichthyosis, and the SmPC lists bone changes including hyperostosis and premature epiphyseal closure after several years of high dose treatment. The stem describes exactly this pattern (Schmorl node plus early disc degeneration at L4/L5 in a young patient on isotretinoin), the recognised imaging correlate of this drug effect rather than a coincidental degenerative spine finding. This is rare but well documented, so clinicians should have a lower threshold to investigate persistent back pain on prolonged or high dose isotretinoin.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/skin-conditions