Black Bruise Under a Toenail: Causes and Next Steps

Tight shoes, running, or stubbing the toe can injure tiny vessels beneath the nail. The colour may be red, purple, brown, or black, and tenderness is more likely soon after an injury.

Blood trapped under the nail is called a subungual haematoma. As the nail grows, an injury-related patch generally moves toward the tip. Fungal changes can also darken or thicken a nail, while pigment may form a stripe rather than a bruise-like patch.

Melanoma of the nail can present with a new dark band or patch, especially when pigment widens, changes, or extends onto nearby skin. Appearance alone cannot reliably separate every cause, so a clinician may examine the nail and surrounding skin closely.

If there was a minor injury, reduce pressure with roomy footwear, keep the toe clean and dry, and avoid piercing or lifting the nail yourself. A clear photograph can help you see whether the mark travels outward with nail growth.

Arrange an assessment if there was no clear injury, the colour stays fixed near the nail base, or the nail becomes thick, crumbly, or repeatedly damaged. A very painful fresh collection of blood may need clinician drainage; this should not be attempted at home.

Seek prompt care after a crushing injury, if the toe looks misshapen, pain is severe or worsening, or you cannot walk comfortably. Redness spreading beyond the nail, warmth, swelling, pus, or fever can indicate infection and also warrants prompt review.

Book a dermatology review for a dark mark without a remembered injury, pigment spreading onto the cuticle or skin, a widening irregular stripe, bleeding, splitting, or a change that does not move with nail growth. Earlier examination is also sensible if circulation, sensation, or wound healing in your feet is reduced.

Ask whether the colour looks like blood, pigment, or infection; whether the nail needs dermoscopic examination; and what change should bring you back. Mention recent footwear pressure, sport, trauma, medicines, previous nail problems, and when you first noticed the mark.