Excessive bruising: causes, red flags and when to see a GP

A bruise is blood that has leaked from small vessels into the tissue under the skin, usually after a knock. Day-to-day bruises have an explanation, appear where you bumped something and fade over a week or two. What makes people worry is a change: bruises that arrive without any memory of an injury, bigger or more numerous than usual, in unusual places, or slow to fade.

Leukaemia UK describes the pattern that merits a check as bruises that appear without a clear cause, bruising more easily than usual, several bruises at once, bruises that seem larger than expected or take longer to fade, bruising in unusual places such as the back, hands or face, and bruising with frequent nosebleeds, bleeding gums, heavier or longer periods or small red or purple pinprick spots on the skin (petechiae).

• Medicines: anticoagulants such as warfarin, apixaban or rivaroxaban, antiplatelet drugs such as aspirin and clopidogrel, anti-inflammatory painkillers and long-term steroids can all increase bruising. The NHS says the main side effect of anticoagulants is that you can bleed too easily, including severe bruising, and that for most people the benefits outweigh the risk.

• Ageing and sun-damaged skin: thin, fragile skin on the forearms and backs of the hands bruises with little force, and is a very common reason for presenting to a GP.

• Minor injuries you did not notice, particularly on the legs and in people who are active or have reduced sensation.

• Liver disease: the NHS lists bleeding or bruising easily among symptoms that may appear as cirrhosis gets worse, alongside itchy skin, jaundice, a swollen tummy and confusion.

• Low platelets, as in immune thrombocytopenia, or reduced production in the bone marrow.

• Inherited bleeding disorders: the NHS lists bruising easily with prolonged bleeding after injury, surgery or a tooth extraction as symptoms of haemophilia, and mentions von Willebrand disease as a condition that can look similar.

• Blood cancers: the NHS lists bleeding or bruising easily or for no reason among the main symptoms of acute myeloid leukaemia.

Leukaemia UK explains that in leukaemia abnormal white blood cells crowd out healthy platelets in the bone marrow. When platelets drop below normal, a condition called thrombocytopenia, even minor knocks can cause bruises, small cuts may bleed longer than expected and bleeding can occur without any obvious injury.

The NHS says the symptoms of acute myeloid leukaemia are not always obvious at first, usually appear over a few weeks, and include feeling very tired or weak, looking more pale than usual, shortness of breath, bleeding or bruising easily, getting ill a lot or being slow to recover, a high temperature, bone or joint pain, a swollen tummy and swollen glands. It stresses that these symptoms are common and can be caused by many conditions, and that having them does not definitely mean leukaemia.

Clotting factor deficiencies are a different mechanism. The NHS says haemophilia is caused by a lack of a clotting factor protein, most people are born with it, and symptoms usually begin in early childhood although they may not be noticed until later.

Because bruising on its own is rarely an emergency, the level of urgency depends on what travels with it.

• Call 999 or go to A&E if bruising or bleeding follows a serious injury, bleeding will not stop, or you are vomiting blood or have black sticky stool.

• Seek emergency care for a rash that does not fade under a pressed glass along with fever, severe headache, stiff neck, drowsiness or confusion: the NHS lists spots or a rash that does not fade when pressed with a glass among meningitis symptoms, and notes it can be harder to see on brown or black skin.

• Ask for an urgent GP appointment or contact NHS 111 if bruising comes with extreme tiredness, paleness, breathlessness, fever, repeated infections, bone pain or swollen glands; the NHS says to ask for an urgent appointment if you have symptoms of acute myeloid leukaemia, and the GP will usually arrange an urgent blood test.

• Leukaemia UK says to speak to a GP if bruising or bleeding is unexplained, is happening more often or more easily, lasts several weeks, or comes with fatigue, night sweats or frequent infections.

• If you take an anticoagulant and develop severe bruising, bleeding that will not stop, blood in urine or stool, or vomiting blood, contact your anticoagulant clinic, GP or NHS 111 promptly rather than stopping the medicine yourself.

Expect questions about when the bruising started, where it appears, whether you remember injuries, how long bruises last, any other bleeding such as nosebleeds, gum bleeding, heavy periods, blood in urine or stool, and how you bleed after dental work or surgery. They will ask about all your medicines, including over-the-counter painkillers and supplements, alcohol intake, liver disease, family history of bleeding problems, tiredness, fevers, night sweats, weight loss and recurrent infections.

The examination looks at the pattern of bruising, any pinprick spots, paleness, jaundice, enlarged glands or liver and spleen, and signs of joint swelling. A skin check helps distinguish bruises from other discolouration.

The first test is a full blood count. Leukaemia UK describes it as a simple blood test that checks levels of different blood cells, including platelets, and can help identify whether an underlying condition may be causing your symptoms. Depending on the result and the story, a GP may add clotting tests, liver and kidney function, vitamin levels and tests for specific clotting factors.

The NHS says haemophilia is diagnosed by a blood test to check the amount of clotting factor, followed by referral to a haemophilia centre. If the blood count suggests a bone marrow problem, an urgent referral to haematology is made, sometimes the same day.

Protect fragile skin by avoiding sharp furniture edges, padding forearms and wearing long sleeves in the garden. Do not stop prescribed anticoagulants or aspirin on your own; the NHS says to speak to your GP, anticoagulant clinic or pharmacist before taking other medicines because some affect how anticoagulants work. Tell any dentist or surgeon that you take them.

Keep a note and dated photographs of new bruises, and record nosebleeds or other bleeding. These records help a clinician judge whether things are changing, and make it easier to explain why you are worried.