Important: This page is for general information only and is not a diagnosis. If you or your child has any of the symptoms described here — such as unusual fatigue, pallor, unexplained bruising, or recurrent infections — please see a doctor promptly. Leukemia is treatable, especially when caught early.

What is leukemia?

Leukemia is a broad term for cancers of the blood cells. The word comes from the Greek for “white blood” — because in many forms of leukemia, the bone marrow makes too many abnormal white blood cells. These abnormal cells crowd out healthy red blood cells, normal white blood cells, and platelets, leading to the shared warning signs of the disease.

Leukemia starts in the bone marrow — the spongy tissue inside bones where blood cells are made. Normally, blood stem cells mature step by step into red blood cells (which carry oxygen), white blood cells (which fight infection), and platelets (which stop bleeding). In leukemia, this process breaks down: immature, abnormal cells multiply rapidly and do not function properly.

The type of leukemia depends on two things: which cell type became cancerous (myeloid or lymphoid), and whether the disease progresses quickly (acute) or slowly (chronic). The four most common types are:

  • Acute Myeloid Leukemia (AML) — involves myeloid cells (the family that gives rise to red blood cells and platelets); progresses rapidly; most common acute leukemia in adults.
  • Acute Lymphoblastic Leukemia (ALL) — involves lymphoid cells; progresses rapidly; most common cancer in children younger than 15.
  • Chronic Lymphocytic Leukemia (CLL) — involves lymphoid cells; usually progresses slowly; one of the most common leukemias in adults; rarely occurs in children.
  • Chronic Myeloid Leukemia (CML) — involves myeloid cells; usually progresses slowly; occurs mainly in adults, rarely in children.

Leukemia occurs most often in adults older than 55, but it is also the most common cancer in children younger than 15. What unites all four types is their origin — they all arise from the blood and bone marrow — and they share many of the same early warning signs.

Common warning signs

Because leukemia affects the blood, its warning signs are linked to what happens when healthy blood cells are crowded out. As abnormal leukemia cells increase, there is less room for healthy red blood cells, white blood cells, and platelets. This leads to the following symptoms, which are common across all major leukemia types:

  • Extreme fatigue or weakness — low red blood cells (anaemia) means the body cannot carry enough oxygen
  • Pallor (pale skin or loss of normal skin colour)
  • Fever without a clear infection, or repeated infections that do not go away — because abnormal white blood cells cannot fight germs properly
  • Easy bruising or bleeding — small flat dark-red spots under the skin (petechiae), bleeding gums, or nose bleeds — because platelet counts are low
  • Painless swelling of lymph nodes — in the neck, armpits, or groin (more common in CLL and ALL)
  • Pain or a feeling of fullness below the ribs on the left side — caused by an enlarged spleen
  • Bone or joint pain (especially in children with ALL)
  • Drenching night sweats
  • Weight loss for no known reason
  • Shortness of breath

Early-stage CLL in particular may cause no symptoms at all and be found only on a routine blood test. CML may also be silent in the early (chronic) phase. Acute leukemias (AML, ALL) tend to develop warning signs quickly — often within four to six weeks before diagnosis.

These symptoms are caused by many conditions other than leukemia. But they should always be evaluated by a doctor, especially if they persist, come on suddenly, or occur together.

Risk factors

Different leukemia types have different risk factors. No single risk factor guarantees that a person will or will not develop leukemia, but knowing them can help guide who needs closer monitoring.

For AML, possible risk factors include:

  • Older age and being male
  • Smoking
  • Previous chemotherapy or radiation therapy for another cancer
  • Exposure to radiation or the chemical benzene
  • A personal history of a blood disorder such as myelodysplastic syndrome
  • Certain inherited syndromes

For CML, the key risk factor is an acquired gene change — a chromosomal rearrangement called the Philadelphia chromosome — in which part of chromosome 9 switches places with part of chromosome 22, creating a gene (BCR::ABL1) that drives uncontrolled white blood cell production. This change is not inherited from parents.

For childhood ALL, possible risk factors include Down syndrome, certain inherited genetic conditions, past exposure to radiation, and some other genetic syndromes. Most children who develop ALL have no identified risk factor.

For CLL, the main risk factors identified include age, being male, and family history — but many cases arise without any clear risk factor.

When to seek medical attention

See a doctor if you or your child has any of the following:

  • Extreme or new-onset fatigue that does not improve with rest, especially with pallor
  • A fever lasting more than a few days without an obvious cause, or recurrent infections
  • Unusual bruising, bleeding gums, frequent nosebleeds, or small flat red spots under the skin
  • Painless lumps in the neck, armpits, or groin that persist for more than two weeks
  • Bone or joint pain (especially in children) — this can be the first sign of ALL
  • Persistent pain or fullness below the left ribs
  • Unexplained weight loss of several kilograms over a few months
  • Drenching night sweats for more than two weeks

For children especially, do not dismiss persistent fatigue, pallor, or bone pain as “growing pains.” Childhood leukemia is the most common childhood cancer, and early diagnosis is strongly associated with better outcomes.

How is leukemia diagnosed?

Tests that examine the blood and bone marrow are used to diagnose leukemia. The evaluation usually starts with a blood test and, if leukemia is suspected, moves to a bone marrow procedure for confirmation.

Blood tests:

  • Complete blood count (CBC) with differential — checks the numbers and types of red blood cells, white blood cells, and platelets; an abnormal CBC is often the first sign that leukemia is present
  • Peripheral blood smear — examines the shape and appearance of blood cells under a microscope; may show blast cells (immature leukemia cells)
  • Blood chemistry studies — measures substances in the blood that can indicate disease

Bone marrow procedures:

  • Bone marrow aspiration and biopsy — a hollow needle is inserted into the hip bone under local anaesthesia to remove a sample of bone marrow for examination under a microscope; this is the key test to confirm leukemia, determine the type, and plan treatment

Molecular and genetic tests done on blood or bone marrow samples:

  • Cytogenetic analysis — examines chromosomes in cells for abnormalities such as the Philadelphia chromosome (in CML)
  • Flow cytometry — identifies leukemia cells based on proteins on their surface; used to classify leukemia type
  • Molecular testing (FISH, RT-PCR) — looks for specific gene changes that affect treatment choice and prognosis
  • Immunophenotyping — identifies leukemia cells by the markers on their surface

Other tests that may be needed:

  • Lumbar puncture (spinal tap) — for AML and ALL, a sample of cerebrospinal fluid is checked to see if leukemia cells have spread to the brain and spinal cord
  • CT scan or chest X-ray — to check whether lymph nodes, the spleen, or other organs are enlarged

Getting a second opinion from a specialist or a cancer centre is reasonable and often encouraged, especially before starting treatment. You will need to share your pathology report, slides, and blood test results with the second doctor.

Treatment basics

Treatment for leukemia depends on the type, the patient’s age and overall health, molecular test results, and how advanced the disease is at diagnosis. You and your cancer care team will work together to decide a plan. The main types of treatment used are:

Chemotherapy — drugs that stop cancer cell growth; the backbone of treatment for most leukemia types. For AML and ALL, treatment is divided into phases: remission induction (to kill leukemia cells and bring the disease under control) and consolidation or maintenance (to kill remaining cells and prevent relapse).

Targeted therapy — drugs that attack specific features of leukemia cells rather than all dividing cells:

  • CML is now primarily treated with tyrosine kinase inhibitors (TKIs) such as imatinib, dasatinib, nilotinib, or asciminib, which block the abnormal protein produced by the Philadelphia chromosome; this has transformed CML from a life-threatening disease into a manageable chronic condition for most patients
  • CLL may be treated with TKIs (ibrutinib, acalabrutinib, zanubrutinib), BCL2 inhibitors (venetoclax), or monoclonal antibodies (rituximab, obinutuzumab)
  • AML has several approved targeted drugs including midostaurin (for FLT3-mutant AML), venetoclax, and others

Immunotherapy — treatments such as CAR T-cell therapy, blinatumomab, and checkpoint inhibitors are used for certain leukemia subtypes, especially relapsed or difficult-to-treat cases.

Stem cell transplant (bone marrow transplant) — high-dose chemotherapy is given to destroy cancer cells and the patient’s existing bone marrow; stem cells from a donor (allogeneic) or the patient themselves (autologous) are then infused to rebuild the blood system; used in high-risk AML, relapsed ALL, and CML that does not respond to TKIs.

Watchful waiting (for CLL) — because CLL often progresses very slowly, patients without symptoms may be monitored closely without starting treatment; treatment begins only when signs or symptoms appear or the disease progresses.

In India, Ayushman Bharat (PM-JAY) provides coverage of up to Rs. 5 lakh per family per year for eligible families, which can cover hospitalisation for chemotherapy, bone marrow biopsy, and supportive care at empanelled hospitals. Ask the hospital’s Ayushman desk before paying out of pocket. Generic imatinib (for CML) is available at reduced prices under the Jan Aushadhi scheme and through government hospital pharmacies, though exact pricing varies.

If you live in Bihar and need leukemia care, Mahavir Cancer Sansthan in Phulwarisharif, Patna — Bihar’s super-specialty cancer centre — has medical oncology and haematology services; notably, paediatric patients are treated free of charge. AIIMS Patna also has a developing oncology department with paediatric oncology clinics. For complex or refractory cases, Tata Memorial Hospital in Mumbai is India’s leading referral centre for leukemia.

Questions to ask your doctor

When you visit a specialist about a possible leukemia diagnosis, you may want to ask:

  1. What type of leukemia is it — AML, ALL, CLL, CML, or another type? How does the type affect my treatment and outlook?
  2. What do the genetic and molecular tests show? Is there a Philadelphia chromosome, FLT3 mutation, or another marker that affects which drugs will work best?
  3. What is the stage or phase of the disease? What does that mean for my treatment plan?
  4. What are my treatment options — chemotherapy, targeted therapy, immunotherapy, stem cell transplant? What are the expected side effects of each?
  5. Will treatment be given as an inpatient (admitted to hospital) or outpatient? How long will each phase last?
  6. Should I get a second opinion before starting treatment?
  7. Is a clinical trial available for my situation? Where is it being conducted?
  8. What supportive care (blood transfusions, antibiotics, growth factors) will I need during chemotherapy?
  9. Is my treatment covered under PM-JAY or any government scheme? What documents do I need?
  10. For children: What are the late effects of treatment on growth, learning, and fertility, and how will they be monitored?

Bring a family member or trusted person to every appointment. Write the answers down.

When urgent care is needed

Please seek urgent medical help — go to the nearest emergency department or call an ambulance — if you have any of the following:

  • A fever of 38°C / 100.4°F or higher during chemotherapy — this is a medical emergency called febrile neutropenia; do not wait for morning
  • Heavy, uncontrolled bleeding — from the gums, nose, or any site that does not stop with pressure
  • Flat red spots (petechiae) spreading rapidly over the body combined with fatigue and pallor
  • Sudden headache, confusion, blurred vision, or weakness in one arm or leg — possible sign that leukemia has affected the brain
  • Severe shortness of breath, chest pain, or a very fast heartbeat
  • Extreme abdominal pain or a sudden large increase in abdominal size
  • A severe allergic reaction (difficulty breathing, facial swelling, full-body rash) within 24 hours of a treatment infusion

In India, you can call 108 or 112 for ambulance services. The Indian Cancer Society helpline is 1800-22-1951 for non-emergency questions and support.

If you are in Bihar and need urgent cancer-related help, the emergency departments at Mahavir Cancer Sansthan (Phulwarisharif, Patna) and AIIMS Patna can provide initial stabilisation and specialist review.