Pernicious Anemia: A History of Observation, Misdiagnosis, and Systemic Blind Spots
Pernicious anemia is often described as a rare autoimmune disease that causes vitamin B12 deficiency and anemia. That description is technically incomplete and historically misleading. The modern failures in diagnosis and treatment of pernicious anemia are not primarily due to lack of evidence or lack of effective therapy. They are the result of a long chain of observational bias, naming inertia, disciplinary silos, and systemic blind spots in medical education—particularly around nutrition and chronic disease.
To understand why pernicious anemia remains underdiagnosed and inadequately treated today, it is necessary to understand how the disease was first observed, how it was defined, and how those early definitions hardened into doctrine even as evidence changed.