Leukemia comprises 33% of all pediatric cancers and is, therefore, the most common cancer that occurs in children and teenagers. The most common type of leukemia is called Acute Lymphocytic Leukemia (ALL), comprising about 75% of all leukemia cases. The remaining are mostly Acute Myelogenous Leukemia (AML) .
However, the survival rate is dependent largely on timely diagnosis and treatment, which is why it is important to recognize signs and symptoms of leukemia in children. Symptoms of leukemia can be very general and can have other causes as well. 
Symptoms associated with low blood cells
Leukemia begins in the bone marrow, which is involved in making blood cells including white blood cells — they are involved in immunity, and red blood cells, which carry oxygen to all cells of the body. Therefore, many of the symptoms in children with leukemia are due to low levels of blood cells.
In particular, symptoms due to low red blood cell counts, which causes anemia, include:
- feeling cold,
- pale skin and
- shortness of breath.
Symptoms from low white blood cell counts include infections. In fact, children with leukemia often get infections that don’t go away or they are constantly getting infections one after another.
Fever is a main sign of infection in children, but some children with leukemia may have a fever despite no infection.
Platelets are involved in stopping bleeding in patients. Children with leukemia can have low platelet counts, which causes:
- uncontrolled bleeding,
- easy bruising,
- frequent nosebleeds and
- bleeding gums .
Swelling of organs
Another symptom of leukemia is the swelling of the abdomen or the belly. Leukemia cells gather in the liver and spleen, which makes those organs bigger, leading to what is called hepatomegaly (enlargement of the liver) or splenomegaly (enlargement of the spleen).
Another issue associated with the hepatomegaly and splenomegaly is that when these organs get large enough, they press against other organs such as the stomach, which leads to a child losing their appetite and subsequent weight loss. The pressing causes the child to feel full after eating very little food .
One of the major symptoms of leukemia is swollen lymph nodes
Some types of leukemia cells can spread to lymph nodes, which can cause swelling and can either be seen or felt as a lump under the skin. These are generally present on the side of the neck, in the underarm, above the collar or in the groin. There are also lymph nodes within the chest that can swell, but these are not felt but rather seen using imaging tests like CT scan or MRIs.
Enlargement of thymus
Since some types of leukemia affect structures of the chest including lymph nodes and the thymus, which is a small structure located in front of the lungs, leukemia patients often have a cough and can have trouble breathing.
The thymus is also located next to the superior vena cava, which is a large vein that carries blood from the head and arms to the heart. When the thymus becomes enlarged, it can press against this vein, which causes the blood to back up in the veins. This leads to swelling in other parts such as face, neck, arms and the upper part of the chest, which also cause a blue-red skin color. It may, in rare circumstances, cause headaches and dizziness if it affects the brain .
The build-up of leukemia cancer cells on the surface of the bone or on the inside of joints can cause pain, which is also a symptom of leukemia . In some rare cases, children with leukemia have advanced enough to have the cancer spread to the brain and spinal cord before diagnosis. If this occurs, then symptoms such as
- inability to concentrate,
- issues with balance and
- blurred vision can occur.
In cases of patients with AML, leukemia may spread to the gums, which can cause swelling of the gums as well as pain and bleeding .
It can also often spread to the skin, which can cause small, dark spots that look like a common rash. A gathering of AML cells in one area under the skin or in different parts of the body are called chloroma or granulocytic sarcoma.
One of the rarer symptoms of leukemia in children, which is related to AML, is being extremely tired, weak and slurring of speech. This occurs due to high numbers of leukemia cells in the blood, which cause it become too thick and viscous and lead to a slowdown of the circulation of blood through the small blood vessels in the brain .
There are certain children that have a higher risk of developing leukemia, particularly in children with
- Li-Fraumeni syndrome or
- Down’s syndrome.
Another subset of pediatric patients that are more likely to develop leukemia are patients that have already been treated with chemotherapy or radiation therapy for the treatment of other cancers as well as children that have undergone organ transplant and are taking immunosuppressing drugs. Therefore, these children should be closely monitored for the development of these symptoms.
Nevertheless, if there is an existence of some of these symptoms in a child, a doctor should be consulted immediately and the child should be treated promptly .