What Are the Early Signs and Symptoms of Blood Cancer and When Should You Get Checked?

Most of us have days when we feel unusually tired, notice a bruise we cannot explain or find a small lump in the neck. In many cases, there is a far more common explanation, such as a minor injury or infection. Most people with these symptoms do not have blood cancer.

Still, it is worth paying attention when a change does not settle, keeps returning, gets worse or appears alongside other unusual symptoms. Speaking to a doctor can help identify the cause and determine whether any tests are needed.

Blood cancer is not one disease. It includes leukaemias, lymphomas, multiple myeloma and other cancers affecting blood-forming or immune-system cells. Because these diseases affect the body differently, their early symptoms can vary. Some develop quickly, while others may cause few or no symptoms initially and are discovered through a blood test.

Knowing what to look for can help you decide when it is worth getting checked without assuming that every symptom is cancer.

What Are the Most Common Possible Signs of Blood Cancer?

Blood cancer does not usually reveal itself through one clear, unmistakable symptom. People may notice different changes, and many of these can also occur with common illnesses or other health conditions.

Changes worth paying attention to include:

• Feeling unusually tired for a long time
• Infections that keep returning or take longer than expected to clear
• A fever without an obvious cause
• Night sweats that soak your clothes or bedding
• Bruising easily or bleeding without a clear reason
• Small red or purple spots appearing under the skin
• Painless lumps or swelling in the neck, armpit or groin
• Losing weight without trying
• Feeling unusually weak or short of breath
• Bone or back pain that does not settle
• Ongoing fullness or discomfort beneath the ribs

Having one of these symptoms does not mean that you have blood cancer. What matters is whether the symptom continues, becomes more noticeable or appears alongside other unexplained changes. If that happens, it is sensible to speak to a doctor and have it checked.

1. Unusual or Persistent Tiredness

We all feel tired after a busy day, poor sleep or a stressful week. The tiredness worth paying attention to is different. It may feel unusual for you, continue despite getting enough rest or make everyday activities feel harder than they normally would.

Some blood cancers can affect the bone marrow’s ability to produce healthy red blood cells. This can lead to anaemia, which means the body does not have enough red blood cells or haemoglobin to carry oxygen effectively.

You may feel weak, look paler than usual or become breathless while walking, climbing stairs or doing activities that were previously comfortable.

Fatigue is extremely common and has many non-cancer causes, including iron deficiency, infections, sleep problems and other medical conditions. Persistent unexplained fatigue is therefore a reason to be assessed, not a reason to assume you have cancer.

2. Frequent or Persistent Infections

White blood cells help protect the body from infection. Some blood cancers interfere with the production or normal function of these cells.

This can sometimes lead to repeated infections, infections that are difficult to clear, or unexplained fever.

Acute leukaemias, for example, may cause fever and infections alongside fatigue, bruising or bleeding.

Most infections are not caused by cancer. However, if infections keep returning or occur together with other unexplained symptoms, speak with a doctor.

3. Unexplained Bruising or Bleeding

Most people occasionally find a bruise and cannot remember how it happened. It becomes more important to have it checked when bruises appear frequently, develop without any clear injury or are accompanied by unusual bleeding.

Platelets help the blood clot and stop bleeding. Some blood cancers can affect how many healthy platelets the body produces. You may notice:

• Bruises appearing without an obvious cause
• Bruising more easily or more often than usual
• Frequent nosebleeds
• Bleeding from the gums
• A small cut that takes longer than expected to stop bleeding
• Pinpoint red or purple spots under the skin, known as petechiae

Leukaemia is one possible cause of easy bruising, bleeding or petechiae, but it is not the only one. Certain medicines and non-cancerous blood conditions can cause similar changes.

Speak to a doctor if the bleeding or bruising is new, keeps happening or appears alongside other unexplained symptoms.

4. Painless Swollen Lymph Nodes

Lymph nodes are small, bean-shaped structures that help the body respond to infection. You can feel some of them in areas such as the neck, armpits and groin.

They often become swollen when you have a cold, sore throat or another infection and usually reduce in size as you recover. A lump may need closer attention if it is painless, has no obvious cause or does not go away.

Lymphoma can cause painless swelling of the lymph nodes. Some people may also experience unexplained fever, night sweats that soak their clothes or bedding, weight loss, ongoing tiredness or itching.

Most swollen lymph nodes are not caused by lymphoma. However, a lump that remains enlarged or cannot be explained by a recent infection should be examined by a doctor.

5. Drenching Night Sweats or Unexplained Fever

A warm room, heavy bedding, menopause, infections and some medicines can all cause sweating at night.

The symptom associated with some blood cancers is generally more significant. Patients may describe drenching night sweats, sometimes enough to soak sleepwear or bedding.

Unexplained fever may also occur.

These symptoms are seen in some lymphomas and leukaemias, particularly when they occur alongside swollen lymph nodes, weight loss, fatigue or other unexplained changes.

6. Unexplained Weight Loss

Losing weight because you have changed your diet or become more active is different from losing weight without trying.

Unintentional weight loss can occur with several illnesses, including some blood cancers.

It is particularly worth discussing with a doctor when weight loss is unexplained and occurs with symptoms such as persistent fever, drenching night sweats, swollen lymph nodes or ongoing fatigue.

There is no need to wait until a particular amount of weight has been lost before mentioning an unexplained change to your doctor.

7. Persistent Bone or Back Pain

Bone pain is not a typical symptom of every blood cancer, but it can be particularly important in multiple myeloma, a cancer involving plasma cells in the bone marrow.

Myeloma can weaken bones and may cause persistent pain, particularly in the back or ribs, as well as fractures, fatigue, frequent infections or weakness. It can also affect kidney function and raise the calcium level in the blood.

Persistent unexplained bone pain should therefore not simply be assumed to be part of aging.

Can Blood Cancer Be Present Without Symptoms?

Yes.

Some slower-growing blood cancers may cause few or no symptoms initially. Chronic lymphocytic leukaemia (CLL), for example, may first be discovered when a routine blood test shows an abnormal result.

Similarly, some plasma-cell conditions may be detected during blood or urine testing performed for another reason.

This does not mean that people without symptoms need routine blood-cancer testing. For people without a specific indication, there is no single general screening test that can rule out all blood cancers. Testing should be guided by symptoms, examination, medical history and clinical judgement.

When Should You Get Checked?

Arrange a medical assessment if you develop symptoms that are unexplained, persistent, worsening or unusual for you, especially when several occur together.

Examples include persistent fatigue with paleness or breathlessness, unexplained bruising or bleeding, recurrent infections, unexplained fever, drenching night sweats, unexplained weight loss, persistent swollen lymph nodes or persistent bone pain.

The National Cancer Institute advises seeing a doctor when symptoms do not improve after a few weeks. However, some possible blood-cancer presentations should be assessed sooner rather than waiting several weeks.

For example, NICE recommends considering a very urgent full blood count, within 48 hours, for adults when leukaemia is suspected because of unexplained symptoms such as pallor, persistent fatigue, fever, persistent or recurrent infection, widespread swollen lymph nodes, bone pain, bruising or bleeding.

You do not need to decide for yourself whether you meet a cancer-referral threshold. Tell your doctor what you have noticed, when it started and whether it is changing.

What Tests May Be Done First?

The first step is usually not an extensive cancer scan.

Your doctor may ask about your symptoms and medical history, examine you for enlarged lymph nodes or other findings, and arrange blood tests.

A common starting test is a complete blood count (CBC), also called a full blood count. It measures red blood cells, different types of white blood cells, platelets and haemoglobin.

Depending on the findings and symptoms, further tests may include:

• A blood film, which allows blood cells to be examined more closely
• Additional blood tests
• Tests for abnormal proteins if myeloma is suspected
• Imaging
• A lymph-node biopsy if lymphoma is suspected
• Bone-marrow testing when certain leukaemias, myeloma or other blood disorders are being investigated

No single test diagnoses every blood cancer. A biopsy or bone-marrow examination may be required to establish the exact diagnosis in some cases.

An abnormal CBC also does not automatically mean cancer. Many infections, nutritional deficiencies, medicines and other conditions can change blood counts.

When Should You Seek Urgent Medical Care?

Most symptoms discussed in this article do not require emergency care, but they should still be assessed by a doctor if they are persistent, worsening or concerning.

Seek urgent or emergency medical care if you have severe difficulty breathing, heavy or uncontrolled bleeding, fainting or loss of consciousness, new confusion, severe weakness, or another sudden serious deterioration.

If a blood test has already shown a major abnormality and your doctor has advised urgent specialist assessment, follow that advice promptly.

What Should You Tell Your Doctor?

You can make the appointment more useful by noting:

• When the symptoms started
• Whether they are getting worse
• How often infections or fevers occur
• Whether bruising or bleeding has an obvious cause
• Whether you have noticed lumps and whether they are changing
• Any unintentional weight change
• Medicines and supplements you take
• Previous blood-test results, if available

You can also ask: “Would a full blood count or another test be appropriate for these symptoms?”

The goal is not to diagnose yourself. It is to give your doctor enough information to decide what needs investigating.

The Main Takeaway

The early signs of blood cancer can be easy to overlook because symptoms such as tiredness, fever, bruising and swollen lymph nodes are also caused by many common conditions.

What deserves attention is a symptom that is unexplained, persistent, worsening, unusual for you, or appearing alongside other concerning changes.

Blood cancer cannot be diagnosed from symptoms alone. A medical assessment, examination and appropriate tests are needed to find the cause.

If something does not feel right or a symptom is not improving, getting checked is more useful than trying to determine from symptoms alone whether you have cancer.

References

1. PDQ® Adult Treatment Editorial Board. PDQ Acute Lymphoblastic Leukemia Treatment—Patient Version. Bethesda (MD): National Cancer Institute; updated 12 May 2025. Available at: https://www.cancer.gov/types/leukemia/patient/adult-all-treatment-pdq. PMID: 26389283
2. PDQ® Adult Treatment Editorial Board. PDQ Acute Myeloid Leukemia Treatment—Patient Version. Bethesda (MD): National Cancer Institute; updated 16 May 2025. Available at: https://www.cancer.gov/types/leukemia/patient/adult-aml-treatment-pdq. PMID: 26389377
3. PDQ® Adult Treatment Editorial Board. PDQ Non-Hodgkin Lymphoma Treatment—Patient Version. Bethesda (MD): National Cancer Institute; updated 22 August 2024. Available at: https://www.cancer.gov/types/lymphoma/patient/adult-nhl-treatment-pdq. PMID: 26389337
4. PDQ® Adult Treatment Editorial Board. PDQ Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment—Patient Version. Bethesda (MD): National Cancer Institute; updated 17 November 2023. Available at: https://www.cancer.gov/types/myeloma/patient/myeloma-treatment-pdq. PMID: 26389437
5. National Institute for Health and Care Excellence. Suspected cancer: recognition and referral. NICE guideline NG12. London: National Institute for Health and Care Excellence; published 23 June 2015; updated 15 April 2026. Available at: https://www.nice.org.uk/guidance/ng12
6. National Cancer Institute. Tests and Procedures Used to Diagnose Cancer. Bethesda (MD): National Cancer Institute, National Institutes of Health; updated 17 January 2023. Available at: https://www.cancer.gov/about-cancer/diagnosis-staging/diagnosis

Medical disclaimer: This article is intended for patient education and does not diagnose blood cancer or replace individual medical advice. Symptoms described here can have many causes. A qualified healthcare professional should assess persistent or concerning symptoms.