Isotretinoin induced small vessel vasculitis: a life-threatening pulmonary-renal syndrome-a case report.

Oral isotretinoin is a synthetic analog of vitamin - A, reserved for cases with severe resistant acne. We hereby report a case of drug-induced vasculitis (DV) from isotretinoin exposure leading to life-threatening pulmonary-renal syndrome requiring immunosuppression and plasmapheresis. A previously healthy 21-year-old female receiving oral isotretinoin presented with a 10-day history of worsening myalgias, arthralgias, and abdominal pain. Soon after admission she progressed to severe pulmonary-renal syndrome requiring intubation and renal replacement therapy. Urinalysis revealed >50 dysmorphic RBC with casts and renal ultrasound was unremarkable. Serological testing was only positive for antineutrophil cytoplasmic antibodies (ANCA) at 1:80 with Anti- proteinase 3 (PR3) at 830 AU/mL and Anti-histone Ab at 2.9. As clinical presentation and serology are highly suggestive of ANCA associated DV, plasmapheresis, and rituximab were also initiated along with the continuation of steroids. She clinically improved but remained dialysis dependent and received a live donor renal transplant. The temporal relationship of symptom onset and drug initiation with no other possible identifiable etiologies-DV in our case was attributed to isotretinoin exposure. Though considered safe, oral Isotretinoin in rare instances can cause the life-threatening pulmonary-renal syndrome. Given its widespread use, it is prudent that prescribers should educate patients regarding the possible symptoms of vasculitis and to seek immediate medical attention when warranted. Physicians should also be vigilant of this complication and should act swiftly to avoid uneventful outcomes.