Reframing Topical Steroid Rebound: The Calcium–Pericyte–Hypoxia Axis as Terrain Collapse

This paper presents a distilled causal sequence underlying Topical Steroid Rebound Phenomena (TSRP), derived from the systems biology framework established in Decoding TSRP: The Pericyte Connection (doi.org/10.5281/zenodo.16907869). It isolates the primary mechanism by which exogenous topical steroid use results in systemic rebound collapse. Framed as a three-part equation—(1) blanching as pharmacodynamic endpoint, (2) calcium-activated pericyte constriction as mechanism of action, and (3) hypoxic terrain collapse as outcome—the model clarifies the distinction between drug withdrawal and vasoregulatory failure. This concise summary is intended to support conceptual clarity and translational coherence across adjacent fields.