Which condition is characterized by painful blue fingers or toes along with hemolytic anemia?

The condition characterized by painful blue fingers or toes along with hemolytic anemia is cold agglutinin disease. This disorder is an autoimmune hemolytic anemia that occurs when cold agglutinins, which are antibodies that agglutinate red blood cells at lower temperatures, lead to hemolysis — the destruction of red blood cells.

In colder environments, these antibodies bind to the surface of red blood cells, causing them to clump together and eventually be targeted for destruction by the immune system, primarily in the spleen. The phenomenon of painful, blue fingers or toes, known as acrocyanosis, occurs when there is decreased blood flow due to the agglutination, leading to ischemia in the extremities.

The presence of hemolytic anemia is indicated by symptoms such as fatigue, jaundice, and a reticulocytosis (increased reticulocyte count), which is the body's response to increased red blood cell destruction. The association of cold temperatures with symptomatic exacerbation in cold agglutinin disease clearly differentiates it from other anemias that do not typically present with such symptoms in response to cold exposure.

In contrast, sickle cell disease primarily leads to painful vaso-occlusive crises and