Molecular mechanisms and clinical tapering strategies for Janus kinase inhibitor relapse in inflammatory dermatoses

Janus kinase (JAK) inhibitors have revolutionized the management of inflammatory dermatoses over recent decades; however, discontinuation is frequently associated with rapid disease recurrence, known as the “relapse” phenomenon, which complicates long-term disease control. Current evidence on the molecular pathophysiology of JAK inhibitor relapse emphasizes the unique pharmacodynamics of Type I inhibitors, which bind the kinase in its active conformation. This binding paradoxically stabilizes primed hyperphosphorylated JAKs and depletes Suppressors of Cytokine Signaling (SOCS) proteins, resulting in a “pharmacokinetic cliff” where pathway suppression is abruptly lost upon drug clearance. This review further categorizes clinical outcomes based on the velocity of the underlying pathology, contrasting the high relapse potential driven by rapid neural or cytotoxic reactivation in atopic dermatitis and alopecia areata against the slower, structural relapse seen in psoriasis. Finally, we propose evidence-based management frameworks, advocating for “slope of reduction” strategies that prioritize dose de-escalation over frequency extension to maintain steady-state suppression, providing a rational approach to safer deprescribing in clinical practice.