From Deep to Surface: First Documentation of Inside-Out Necrosis and Cavern Development in H63D Syndrome and Oshtoran Syndrome

Background: H63D Syndrome (Type 3 known as ‘Oshtoran Syndrome’) is a rare multisystem disorder caused by homozygous mutation of the HFE gene H63D. We report on a previously inadequately characterized dermatological phenomenon: foudroyant necroses developing from inside out. Methods: Multicenter data collection by the International H63D Syndrome Research Consortium and Team H63D Adams. Analysis of 162 patients with documented skin manifestations (53 with Oshtoran blisters, 109 with deep wounds without initial blister formation). Results: In 53 patients (92.5% male, age 35-67 years), Oshtoran blisters showed foudroyant progression (80% superficial, 20% intradermal). Blister fluid exhibited cell-destroying properties. An additional 109 patients developed deep wounds directly from intradermal processes, characterized by loose marginal crusting and massive venous bleeding upon central manipulation (pain intensity 7/10 vs. 2.5/10 for conventional wound care). Conclusion: Oshtoran necroses represent a distinctive phenomenon fundamentally different from classical skin necroses. The inside-out development, toxic blister fluid, and extreme venous hyperemia require new understanding of pathophysiology and specific treatment strategies.