Symptoms of childhood ALL — acute lymphoblastic leukaemia

Paleness (pallor) and fatigue are among the earliest and most common symptoms of ALL leukemia in a child. They arise because leukaemia cells crowd the bone marrow and disrupt the production of healthy red blood cells, causing anaemia. Red blood cells carry oxygen to every organ in the body; when their numbers fall, children become noticeably pale — particularly visible in the gums, inner eyelids, and lips — and they feel exhausted even without physical activity. This is not the ordinary tiredness that comes after a busy day and improves with sleep. It is a persistent, deepening exhaustion that gets in the way of normal play and does not resolve with rest. If your child looks consistently pale and is more tired than usual for more than two weeks without an obvious cause such as a recent illness, a Complete Blood Count (CBC) is the right first step. Most causes of pallor and fatigue in children are not leukaemia — but only a blood test can confirm this.

When leukaemia cells crowd the bone marrow, platelet production also falls. Platelets are the tiny blood cells responsible for clotting. When their count drops, children bruise from minor bumps that would normally leave no mark, bleed from small cuts for longer than expected, develop nosebleeds that are difficult to stop, and may experience bleeding gums. Parents sometimes also notice tiny flat red or purple pinprick spots on the skin — these are called petechiae, and they appear when small blood vessels bleed under the skin. Petechiae most commonly appear on the lower legs, around the ankles, or on the torso. They look like a rash of very small dots but do not fade when you press on them (unlike a viral rash, which does fade under pressure — a simple check called the “glass test”). Easy bruising and petechiae alongside tiredness and pallor significantly raise the concern for a blood disorder and warrant a blood test urgently, within one to two days rather than at the next available routine appointment.

Fever is a very common symptom in children, and the vast majority of fevers are caused by ordinary viral or bacterial infections. However, in ALL leukemia, fever can occur for two distinct reasons that are worth understanding. First, leukaemia itself can directly trigger a fever response through the substances that leukaemia cells release into the bloodstream. Second, because the normal infection-fighting white blood cells are crowded out by abnormal leukaemia cells, children with ALL are genuinely more vulnerable to infections — so they may catch ordinary infections but find them harder to shake and more likely to recur. The fever pattern that concerns paediatric oncologists is: a fever that lasts more than a week without a clear source, a fever that keeps coming back every few weeks, or a child who seems to be ill with one infection after another with very short recovery periods between them. This kind of recurring or prolonged fever, especially combined with pallor, bruising, or bone pain, is a reason to do a blood count within days.

Bone or joint pain is one of the recognised ALL signs in children, and it is sometimes the symptom that first brings a child to a doctor. It happens because leukaemia cells accumulate inside the hollow spaces of the bone marrow, increasing pressure within the bone. This pressure creates a deep, achy pain that is often worst at night, when a child is lying still and has nothing to distract them from it. The pain can affect any bone but most commonly involves the long bones of the legs (thighs, shins), the arms, the spine, or the hips. It may also present as joint pain resembling arthritis, particularly in the ankles or knees — which is one reason ALL is sometimes initially misdiagnosed as juvenile arthritis. The key distinguishing features are: pain that is present during the day as well as at night, pain in a specific location rather than diffuse across both limbs, and pain that comes alongside other ALL symptoms like pallor, bruising, or persistent fever. See also our dedicated page: Bone Pain at Night in Children.

Lymph nodes are small, bean-shaped glands found throughout the body, particularly in the neck, armpits, groin, and abdomen. They are a normal part of the immune system and commonly swell briefly during infections — you may have noticed your child’s neck glands becoming temporarily tender during a throat infection or cold. In ALL, leukaemia cells can migrate from the bone marrow into the lymph nodes and cause them to enlarge. The key difference from infection-related swelling is the character of the swelling: ALL-related lymph node enlargement tends to be painless (the glands are not sore to touch), firm (rather than soft and bouncy), persistent (does not reduce after the infection resolves), and may affect multiple sites at the same time. A single enlarged gland in the neck that appeared during a recent cold and is slowly shrinking is almost always benign. A firm, painless, persistent swelling in the neck or armpit — especially if the child also has pallor, tiredness, or unexplained fever — needs a blood test and clinical assessment.

In ALL, leukaemia cells can spill out of the bone marrow and accumulate in the spleen and liver, two organs that sit in the upper abdomen. When either or both of these organs enlarge — a condition called hepatosplenomegaly — children and parents may notice that the belly looks or feels larger than usual, that the child feels full quickly when eating, that there is a firm mass or firmness in the upper left or right abdomen, or that the child says their tummy feels uncomfortable even without a stomach bug. In infants and younger children, the abdomen may look visibly distended. Parents sometimes attribute this to constipation or the child simply “eating too much” in the early stages. A doctor can detect hepatosplenomegaly with a gentle abdominal examination — it is one of the physical findings that triggers blood tests. If you can feel a firm, non-tender mass in your child’s upper abdomen, see a doctor within one to two days.

Many parents of children later diagnosed with ALL recall that the child stopped wanting to eat in the weeks or months before diagnosis — often at first attributed to fussiness, a stomach bug, or a growth phase. In ALL, loss of appetite (anorexia) can result from the body’s general response to the disease, the presence of an enlarged spleen or liver pressing on the stomach and reducing its capacity, or from general unwellness. Weight loss that is noticeable over a period of weeks — particularly when the child is also pale, tired, or running fevers — is a symptom that should not be dismissed as a passing phase. Children who are unwell and losing weight warrant a clinical assessment. A blood count is a reasonable first test for any child with unexplained weight loss lasting more than two weeks alongside any of the other symptoms described on this page. You know your child’s body. If something feels wrong, the right instinct is to get it checked.