Bruising Easily: Common Causes and When Unexplained Bruises Need Checking

Most unexplained bruises have a boring explanation: a bump you didn’t notice, thinner skin with age, or a medicine you take. But sometimes easy bruising is a sign of a blood problem that needs checking. Here’s how to tell the difference.

Imagine getting changed after a shift and finding three purple bruises on your thighs and one on your arm. You can’t remember knocking into anything. Your gums bled a bit when you brushed your teeth this morning too, and you’ve felt unusually tired. Each thing alone seems minor. Together, they’re a reason to get a blood test.

Common, usually harmless causes

• Minor bumps you didn’t notice, especially on the legs
• Ageing: skin gets thinner and blood vessels more fragile, so older adults bruise easily, often on the forearms
• Long-term sun damage to the skin
• Intense exercise
• Being naturally prone to bruising, which often runs in families

Medicines and supplements that increase bruising

• Blood thinners such as warfarin, apixaban and rivaroxaban
• Aspirin, clopidogrel and anti-inflammatory painkillers such as ibuprofen
• Steroid tablets and creams used long term
• Some antidepressants (SSRIs)
• Supplements such as fish oil, ginkgo and high-dose vitamin E

Don’t stop a prescribed medicine without talking to your doctor, nurse or pharmacist first.

Conditions linked to easy bruising

Low platelets, inherited bleeding disorders such as von Willebrand disease, liver disease, heavy alcohol use, vitamin C or K deficiency, and, rarely, blood cancers such as leukaemia.

But when do bruises need checking?

See a doctor or nurse soon if you have:

• Frequent, large or unexplained bruises, especially on the trunk, back or face
• Bleeding gums, frequent nosebleeds or very heavy periods
• Bruising with tiredness, fever, night sweats, weight loss or frequent infections
• A bruise that keeps getting bigger, or doesn’t fade after two weeks
• A family history of bleeding problems, before surgery or dental work

Get urgent help for tiny red or purple spots that don’t fade when you press a glass on them (petechiae), especially with fever or feeling unwell, for blood in urine or stools, or for heavy bleeding that won’t stop.

Unexplained bruises in babies who aren’t yet moving, children with bruises in unusual places, or vulnerable adults can also be a sign of abuse. Healthcare providers are trained to ask about this sensitively.

Sources: NHS (Bruises), US National Heart, Lung, and Blood Institute (Bleeding disorders), American Society of Hematology, NICE guideline on suspected cancer: recognition and referral. This guide is for general information and does not replace advice from your own nurse, doctor or pharmacist.