Systematic review: Sweet syndrome associated with inflammatory bowel disease.

BACKGROUND AND AIMS Sweet syndrome (SS) is a dermatologic condition associated with both IBD and azathioprine use. We performed a systematic review to better delineate clinical characteristics and outcomes of SS in IBD patients. METHODS Peer-reviewed, full-text journal publications from inception to April 2020 in English language and adult subjects with IBD were included. Skin biopsy was required as SS gold-standard diagnosis. Azathioprine-associated SS required recent azathioprine introduction or recurrence of SS after azathioprine re-challenge. RESULTS We included 89 publications with 95 patients (mean age of SS diagnosis: 44 years; 59% female; 20 with azathioprine-associated SS and 75 without). SS was diagnosed prior to IBD in 5.3%, at time of IBD diagnosis in 29.5% and after diagnosis in 64.2%. 91% of patients with SS had known colonic involvement and the majority (76%) had active IBD at diagnosis; 22% had additional extra-intestinal manifestations. Successful therapies for SS included corticosteroids (90.5%), anti-TNF-α inhibitor therapy (14.8%) and azathioprine (11.6%). Azathioprine-associated SS was distinct, with 85% male patients, mean age of SS diagnosis of 50 years and a lower likelihood to be prescribed corticosteroids for treatment (75% vs. 94.7% of non-azathioprine-associated SS, p=0.008). All patients with azathioprine-associated SS improved with medication cessation and developed recurrence after re-challenge. CONCLUSIONS SS may precede or occur with IBD diagnosis in almost one third of cases. Azathioprine and IBD-associated SS present and behave distinctly, especially with regard to gender, age at diagnosis and recurrence risk. Corticosteroids and TNF-α inhibitors have demonstrated efficacy in treating SS in IBD.