Sacroiliitis is a rare adverse reaction of isotretinoin. Review of 67 pts finds median age 21 yrs, onset median 2.5 mos (0-24) post isotretinoin. Sxs: LBP 70%) & hip pain 45%. Dx by MRI (73%) w BME. Full recovery 81% isoretinoin D/C & NSAIDs (< 10% biologics)