What STEERs excoriation disorder? A narrative review, integrative theoretical model, and research agenda

Excoriation Disorder, or Skin Picking Disorder (SPD), is characterized by repetitive self-inflicted skin damage, significant distress, and functional impairment. Despite its prevalence and clinical relevance, SPD remains under-researched, and findings from existing studies are difficult to integrate, limiting their usefulness for intervention development. One contributing factor is the absence of an overarching theoretical framework. Existing explanatory accounts offer important insights but each has limitations when considered in isolation. This article introduces the STEER model (Sensory processing, Temperament, Emotion dysregulation, Events, Reinforcement) as a framework for understanding the development and maintenance of SPD.

We reviewed existing explanatory models of SPD and conducted a narrative synthesis of research findings on sensory-processing abnormalities, temperament and personality vulnerabilities, emotion dysregulation, internal and external triggers and reinforcement mechanisms responsible for development and maintenance of SPD. We also considered how these components may relate to neurobiological systems implicated in SPD.

The STEER model proposes that atypical interoceptive and exteroceptive processing may interact with dispositional traits to increase vulnerability to SPD. These factors can contribute to emotion dysregulation and heighten responses to internal and external triggers, fostering maladaptive self-grooming behaviors. Once initiated, these behaviors are maintained through negative and positive reinforcement, while subsequent distress or skin damage may create new triggers and sustain a self-perpetuating cycle.

The STEER model integrates existing theoretical and empirical work into a testable account of mechanisms underlying SPD. It underscores the importance of sensory-processing mechanisms, identifies research directions, and provides a structure for developing more targeted, mechanism-based interventions.