A bruise describes localized bleeding from smaller blood vessels, which typically doesn't require treatment. A hematoma is a pooling of blood due to larger blood vessel leakage, which might need draining.

In 2026, medical guidance distinguishes between a hematoma and a bruise (contusion) primarily by the severity and the "feel" of the injury. A bruise is a minor injury where small capillaries near the skin surface break, causing the classic flat, purple-to-yellow discoloration that usually fades in two weeks. A hematoma, however, is a more significant collection of blood that pools outside of larger blood vessels. The key sign of a hematoma is palpable swelling; if the area feels like a firm, raised lump or "knot" under the skin, it is likely a hematoma. Hematomas are often more painful, stay tender for a longer period, and can feel warm to the touch. While a simple bruise can be treated with "RICE" (Rest, Ice, Compression, Elevation), a large or rapidly growing hematoma in 2026 should be evaluated by a healthcare professional, especially if it follows a head injury or if you are on blood thinners, as internal hematomas can occasionally be serious or require medical drainage.