Macrophage activation syndrome (MAS) is a life-threatening complication of rheumatic disorder characteristic by excessive production of proinflammatory cytokines. In adults, MAS poses a major clinical challenge due to its rapid progression and high mortality rates. Current first-line treatment regimens, based on paediatric approaches, including haemophagocytic lymphohistiocytosis (HLH)-94 or HLH-2004, do not work for about 30% of adult patients. This unmet need highlights the urgency for targeted therapies and salvage treatments. Janus kinase inhibitors, like ruxolitinib (Rux), are emerging as promising options due to their capacity to selectively block proinflammatory cytokine pathways, offering a new therapeutic strategy for managing MAS in adults.1 2 Previous cases have reported Rux to be a safe and effective therapy, especially in refractory or relapsed HLH, including MAS. …