In modern distributed healthcare systems, ensuring secure communication and authentication among patients, healthcare professionals, and hospitals is critical for safeguarding sensitive medical data. The authentication of each party is necessary to prevent security and privacy threats within the connected network. Not only do these threats result in increased processing overheads, but they also potentially putting patients’ lives at risk, especially in critical situations. While many authentication and security methods proposed in the research literature are centralized and rely on trusted third parties for secure communication, this dependence can lead to longer authentication times, decreased throughput, and added overhead in patient and inter-hospital communications. This research develops a post-quantum decentralized, blockchain-based authentication system optimized for healthcare environments, enhancing security and reducing overhead in distributed hospital networks. Our study shows that the proposed blockchain-based authentication processes across multiple hospitals, lowering latency, energy consumption, and computational overhead. The proposed model outperforms traditional authentication methods, improving throughput and reducing delays in real-time healthcare data exchange.