Aplastic anemia occurs when the bone marrow can’t make enough RBCs. This can be due to a viral infection, or exposure to certain toxic chemicals, radiation, or medications (such as antibiotics, antiseizure drugs, or cancer treatments). Some childhood cancers can also cause aplastic anemia, as can certain chronic diseases that affect the ability of the bone marrow to make blood cells.
High levels of hemoglobin and RBCs help fetal blood carry enough oxygen to developing babies in the relatively oxygen-poor environment in utero. Thus, infants are born with some protection from iron deficiency. After the child is born, more oxygen is available and the baby’s hemoglobin level normally drops to a low point at about 2 months of age, a condition known as physiologic anemia of infancy. This temporary and expected drop in the blood count is considered normal and no treatment is required because the infant’s body soon starts making red blood cells on its own.
Anemia also occurs when the body isn’t able to produce enough healthy RBCs because of an iron deficiency. Iron is essential to hemoglobin production. Poor dietary iron intake (or excessive loss of iron from the body) can lead to iron deficiency anemia, the most common cause of anemia in children. Iron deficiency anemia can affect children at any age, but is most commonly seen in those younger than 2 years old.
Girls going through puberty also have a particularly high risk for iron deficiency anemia because of the onset of menstruation; the monthly blood loss increases the amount of iron they need to consume in their diets.