Acne fulminans is a rare and severe form of acne that may evolve from acne vulgaris,
especially in male adolescents, or occur as an adverse effect of oral isotretinoin.
Arthritis is a serious clinical manifestation when the musculoskeletal system is
compromised by AF and has been reported as a rare adverse effect of isotretinoin.
Involvement of the sacroiliac joints occurs in 21% of acne fulminans cases. We
present the case of a 18-year-old male patient in whom acne fulminans evolved from
acne vulgaris grade IV and after inflammation resolution started treatment with oral
isotretinoin. Within a 30-day period of retinoid treatment he presented with back
pain followed by rapid, progressive inability to deambulate.