Frequent or repeated infections: could they be a sign of leukaemia?
In leukaemia, abnormal white blood cells can leave the immune system unable to fight infection effectively even when white blood cell counts appear normal.
At a glance
- Frequent or persistent infections can sometimes be a sign of leukaemia
- In leukaemia, abnormal white blood cells crowd out healthy white blood cells, weakening the body’s ability to fight infection
- In most cases, repeated infections will not be caused by leukaemia but if they keep coming back, last longer than expected, or occur alongside other symptoms, see your GP
- When you see your GP, ask specifically for a full blood count test
Frequent or repeated infections can sometimes be a sign of an underlying condition, including leukaemia. In people with leukaemia, abnormal white blood cells crowd out healthy white blood cells in the bone marrow, weakening the immune system’s ability to fight bacteria, viruses and other germs.
Why does leukaemia cause frequent infections?
Leukaemia develops in the bone marrow, where all blood cells are made. As abnormal leukaemia cells multiply rapidly, they crowd out the healthy white blood cells the immune system relies on to fight infection. Although leukaemia causes an overproduction of white blood cells, these cells are abnormal and do not function properly meaning the body is left with fewer effective infection fighting cells than it needs.
This is why people with leukaemia may find they pick up infections more easily, struggle to recover from them, or experience infections that keep returning shortly after clearing up. It is also why infections can appear alongside other symptoms of leukaemia, such as persistent fatigue, unexplained bruising, or night sweats, all of which reflect the bone marrow’s reduced ability to produce healthy blood cells.
What might frequent or repeated infections look like?
Signs to be aware of include:
- Infections that happen more often than usual
- Infections that take longer than normal to clear up
- Needing antibiotics more frequently than before
- Getting infections again shortly after recovering from one
Examples of infections include recurrent or persistent chest/throat infections, tonsillitis, dental and skin infections.
When should you see a GP about frequent or repeated infections? 👩🏽⚕️
You should speak to your GP if:
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- Infections are persistent, recurring, or slow to clear up
- Infections occur alongside other symptoms such as fatigue, unexplained bruising, or night sweats
- You have needed antibiotics repeatedly over a short period of time
When you see your GP, ask specifically for a full blood count test.
This is a simple blood test that checks the levels of different blood cells, including white blood cells, and can help identify whether an underlying condition may be causing your symptoms. In most cases, repeated infections will not be caused by leukaemia but persistent or unusual symptoms should always be checked.
Maria’s story
Maria, who works at a hospital, experienced at least three infections in late 2023 and into 2024, which she now recognises as the earliest signs that something was wrong. At the time, each episode was simply put down to having caught an infection.
Frequently asked questions about leukaemia and infections.
No. Frequent infections are very common and have many possible causes, including a weakened immune system from stress, poor nutrition, certain medications, or other underlying health conditions. In most cases, repeated infections will not be related to leukaemia. However, if infections keep returning, last longer than expected, or occur alongside other symptoms such as unexplained fatigue or bruising, it is worth speaking to your GP.
In leukaemia, the bone marrow produces large numbers of abnormal white blood cells that do not function properly. Although white blood cell counts may actually appear high in a blood test, these abnormal cells cannot fight infection effectively. This leaves the immune system weakened and less able to defend the body against bacteria, viruses and other germs, making infections more frequent and harder to recover from.
People with leukaemia can be susceptible to a wide range of infections, including respiratory infections such as coughs and colds, sore throats, mouth ulcers, skin infections, and urinary tract infections. Any infection that seems unusually frequent, severe, or slow to resolve is worth mentioning to your GP, particularly if it occurs alongside other symptoms.
A high white blood cell count can be one indicator of leukaemia, but it is not conclusive on its own. Many conditions can cause elevated white blood cell levels, including infections themselves. A full blood count will show not just the number of white blood cells but also whether the levels of red blood cells and platelets are normal, which helps give a fuller picture. Your GP will interpret the results in the context of your symptoms.
If results are abnormal, doctors may carry out further investigations, such as a bone marrow biopsy, to confirm a diagnosis.
Disclaimer: While we are able to highlight the common signs and symptoms of leukaemia, these symptoms are often caused by other medical conditions. As a charity we are not able to give specific medical advice to patients, but if you have any concerns contact your GP.
Last reviewed: June 2026