Isotretinoin-induced sacroiliitis: Case series of four patients and a systematic review of the literature.

Isotretinoin is the mainstay treatment in severe acne; however, its musculoskeletal adverse effects such as lower-back pain can be disabling. Herein, we present four cases of isotretinoin-induced sacroiliitis with variable severity. We also present a review of the literature of isotretinoin-induced sacroiliitis. All our cases were male and human leukocyte antigen (HLA)-B27 negative. Sacroiliitis was detected a median of 55 (10-120) days after isotretinoin initiation. Two patients were responsive to baseline sulfasalazine and indomethacin treatment, while the other two patients required more intensive treatments: adalimumab in one and methotrexate in the other. We also identified 15 articles describing 33 patients (17 of whom were female) with isotretinoin-induced sacroiliitis. Most of them were responsive to low-to-medium doses of systemic steroids or non-steroidal anti-inflammatory drugs (NSAIDs). Our patients illustrate that severity of isotretinoin-induced sacroiliitis varies from patient to patient.