Published: April 16, 2019 | Updated: November 22, 2021

Leukemia is the most common cancer in children and teens, accounting for almost 1 out of 3 cancers. Most childhood leukemias are acute lymphocytic leukemia (ALL). Most of the remaining cases of leukemia in children are acute myeloid leukemia (AML). Chronic leukemias are rare in children. 

What is leukemia in children?

Cancer is when cells in the body start to grow too much. Almost any cell type in the body can become cancer. Leukemia is a cancer that starts in the bone marrow, the soft inner part of bones, where some cells that form the blood are made. Any of the cells that form blood can become leukemia cells, including white blood cells, red blood cells and platelets. Once one of these cells becomes a leukemia cell, it doesn’t grow as it should. Leukemia cells may reproduce very fast, and don’t die at the time they should. This makes the leukemia cells start to crowd the other healthy cells in the bone marrow. The leukemia cells often spill out into the bloodstream, where they go to other parts of the body and prevent other cell types from working as they should.

Types of leukemia in children

There are two kinds of leukemia: acute (fast growing) and chronic (slow growing). There are several types of each kind. Acute leukemia types include:

• Acute lymphocytic (lymphoblastic) leukemia (ALL): This leukemia starts from a type of white blood cell called lymphocyte in the bone marrow. Lymphocytes are disease-fighting cells that make up lymphoid tissue.
• Acute myelogenous leukemia (AML): This type of leukemia is also called acute myeloid leukemia, acute myelocytic leukemia or acute non-lymphocytic leukemia. This is the second most-common type. AML starts from the myeloid cells that form white blood cells (other than lymphocytes), red blood cells, or platelets.

More adults experience chronic leukemia than children. Chronic leukemia types rarely occur in children. This type is generally harder to treat than acute leukemia. Chronic leukemia types include:

• Chronic myelogenous leukemia (CML): This leukemia rarely occurs in children. During CML, genetic changes happen in myeloid cells, forming an abnormal gene called BCR-ABL. This abnormal gene turns the myeloid cell into a CML cell. CML is often slow growing, but can change into a fast, acute leukemia that can be hard to treat.
• Chronic lymphocytic leukemia (CLL): This leukemia is the most common version in adults. This type is extremely rare in children.

Signs and symptoms of leukemia in children

Signs of leukemia in children are shared by many types of conditions. Most often, these signs are not caused by leukemia. However, if your child has many of these signs, take your child to his or her provider for an exam:

• Anemia (low red blood cell counts): Red blood cells help move oxygen to cells throughout the body. Low red blood cell count signs include:
  • Feeling tired all the time (fatigue)
  • Feeling cold
  • Headaches
  • Pale skin
  • Shortness of breath
  • Weakness
• Bone pain or joint pain: Leukemia cells build up near the surface of the bone or inside joints, causing pain.
• Coughing or breathing issues
• Headaches
• Low white blood cell counts. Signs of low white blood cell counts include:
  • Fever
  • Infections can occur more often, and the illnesses don’t seem to go away. It can also seem like the child has one illness right after another.
• Low blood platelets. Signs of low platelets include:
  • Bleeding gums
  • Bruising or bleeding easily
  • Frequent or severe nosebleeds
• Rashes that look like small, dark spots
• Seizures
• Slurring while talking, with extreme fatigue
• Swelling in the face and arms
• Swelling and bleeding in the gums
• Swollen lymph nodes
• Vomiting
• Weight loss or trouble eating

Talk to your child’s provider about any signs you notice. It’s more likely symptoms are caused by something other than leukemia. Taking steps to get a diagnosis can help your child get the treatment he or she needs.