What causes easy bruising?

Bruises form when small blood vessels leak beneath the skin. Arms and legs may show marks after contact you did not notice. Aspirin, anticoagulants, some steroid medicines, and certain supplements can make bleeding under the skin easier. Sun-damaged or thinner skin also offers less protection to surface vessels. Less commonly, a low platelet count, a clotting problem, liver disease, or heavy alcohol use can contribute. Conditions such as dengue fever and blood disorders can present with bruising alongside other symptoms, but a bruise alone does not identify a specific condition.

Note when the bruising began, where it appears, whether marks follow bumps, and whether the areas are growing. Photographing new bruises can help show change. Do not stop a prescribed blood-thinning medicine without medical advice. Protect the skin from knocks, use a cold pack wrapped in cloth soon after an injury, and eat regular balanced meals. A clinician may review medicines and request a blood count or clotting tests when the pattern is new, widespread, or unexplained.

Arrange prompt medical assessment for bruising that appears suddenly, spreads, keeps returning, or occurs with nosebleeds, bleeding gums, unusually heavy periods, fever, marked tiredness, or unintentional weight loss. Seek urgent care for bleeding that will not stop, severe weakness, confusion, a severe headache after an injury, or bruises with significant abdominal pain. A healthcare professional can decide whether symptoms need same-day testing.

Ask whether any medicine or supplement could be contributing, whether your pattern needs blood tests, and which warning signs should prompt urgent review. Tell the clinician about family bleeding problems, recent infections, alcohol use, and any bleeding from places other than the skin.