Xia, FandiLiu, KristinaLockwood, Stephen J.Butler, Daniel CharlesTsiaras, WilliamJoyce, CaraMostaghimi, Arash2017-10-132017Xia, Fandi D., Kristina J. Liu, Steven J. Lockwood, Daniel C. Butler, William G. Tsiaras, Cara Joyce, and Arash Mostaghimi. 2017. Risk of developing pyoderma gangrenosum after procedures in patients with a known history of pyoderma gangrenosum – a retrospective analysis. Journal of American Dermatology. doi: 10.1016/j.jaad.2017.09.040.0190-9622http://nrs.harvard.edu/urn-3:HUL.InstRepos:34216317Background The risk of postoperative pyoderma gangrenosum (PG) in patients with a known history of PG is unknown. Objective To quantify risk and identify patient/procedure-related risk factors for postsurgical PG recurrence/exacerbation in patients with known history of PG. Methods We retrospectively evaluated the likelihood of postsurgical PG recurrence/exacerbation for all patients with a confirmed diagnosis of PG at Brigham & Women’s Hospital and Massachusetts General Hospital from 2000-2015. Results 5.5% (n=33) of procedures led to recurrence of PG in 15.1% (n=25) of patients. Compared to skin biopsy, small open surgeries had an adjusted odds ratio (aOR) of 8.65 (1.55, 48.33) for PG recurrence/exacerbation; large open surgeries had an aOR of 5.97 (1.70, 21.00); and Mohs surgery/skin excision had an aOR of 6.47 (1.77, 23.61). PG chronically present at the time of procedure had an aOR of 4.58 (1.72, 12.22). Immunosuppression, time elapsed since original PG diagnosis, and procedure location did not significantly influence risk. Limitations Our study is limited by its retrospective nature and relatively small sample size. Conclusion There is a small but clinically meaningful risk of postsurgical PG recurrence/exacerbation in patients with known history of PG; higher risks occur with more invasive procedures and chronically present PG.en-USpyoderma gangrenosumexacerbationpathergypostoperativeprophylaxisrecurrencerisk factorsJournal Article2017-10-0820172017-10-1310.1016/j.jaad.2017.09.040