What should you know about bruised big toe nail causes?

A subungual haematoma is blood trapped beneath the nail after a toe is hit, squeezed, or repeatedly pressed by footwear. The colour may be red, purple, brown, or black, and soreness can be strongest soon after the injury. Tight shoes, running, and a long or uneven toenail can create repeated pressure even when there was no memorable accident.

The mark should gradually move toward the tip as the nail grows. A dark area that begins near the base, changes without an injury, or does not move with growth may need a clinician to distinguish it from other causes of nail colour change. See Discoloured Nails for related nail changes.

Rest the toe, use a cold pack wrapped in cloth for short periods, and wear roomy shoes with a protective toe box. Keep the nail clean and dry, and avoid piercing it at home. Trimming the nail straight across after tenderness settles can reduce catching.

A clinician may assess the nail and surrounding toe, particularly when pressure has caused significant throbbing or the nail is partly detached. Nail Surgery is a specialist option in selected cases, not a self-care step.

Arrange prompt assessment after a crush injury, severe or worsening pain, inability to bear weight, obvious deformity, numbness, an open wound, or a nail that is lifting extensively. Seek review for warmth, pus, spreading redness, or fever. An unexplained dark streak or colour change also warrants examination.

Ask whether the appearance fits a trapped-blood injury, whether the toe needs imaging, and how to protect the nail while it grows out. Ask what changes would suggest infection or a different nail condition.