Sweet syndrome: A retrospective study of 64 cases and proposal of an algorithmic approach to improve investigation and management.

Background: Sweet syndrome (SS) can be categorized as classical Sweet syndrome (CSS), malignancy-associated Sweet syndrome (MASS) or drug-induced Sweet syndrome (DISS). Appropriate categorization of patients with SS and identification of the associated trigger are essential to direct subsequent investigations and follow-up, especially given that 21% of cases are malignancy-associated. However, no published guidelines exist to guide this.

Objective: To analyse the categorization, management and outcomes of patients with SS in order to propose a structured approach for investigation and follow-up.

Methods: Retrospective data collection from the electronic records of patients diagnosed with SS between 1 January 2005 and 31 December 2018. Categorized and non-categorized patients were compared, and the yield rate of investigations and duration of follow-up were analysed.

Results: Sixty-four patients were included with CSS (77%), MASS (20%) and DISS (3%). Of these, 34 (53%) cases were not categorized by the assessing clinicians, three of which were subsequently diagnosed with a malignancy, up to 19 months later. There was no significant difference in investigations performed between categorized and non-categorized patients and the yield rates were modest overall. Follow-up averaged 10.5 (16.8) months; non-categorized patients were followed-up for significantly longer than categorized patients (15.0 (21.2) vs. 5.4 (6.8) months,  < 0.05).

Conclusion: The lack of a structured way to approach patients with SS can lead to under- or over-investigation, diagnostic delays of underlying conditions and unnecessary follow-up. An algorithm is proposed to identify the likely trigger and manage patients accordingly. Larger prospective studies are required to confirm the optimal approach to investigate and follow-up patients with SS.