A decrease in red blood cells that happens when the body can't absorb enough vitamin B-12.
Pernicious anemia is a decrease in red blood cells that happens because the body can't absorb enough vitamin B-12. Common causes include a weakened stomach lining or an autoimmune condition.
Symptoms of pernicious anemia include fatigue and weakness. Untreated, the condition can cause heart and nerve damage.
Treatment for pernicious anemia involves vitamin B-12 shots or pills.