What should you know about black pinky toenail?

The smallest toe is easily squeezed by narrow shoes and repeatedly knocked during walking or sport. Trapped blood may look dark red, purple, brown or black. The mark should gradually move towards the nail tip as a healthy nail grows from the base.

A recent stubbed toe, long walk, run, or tight footwear supports a bruised nail, also called a subungual haematoma. Fresh bleeding can throb because pressure builds beneath the hard nail plate. An older bruise may no longer hurt and can remain visible for months while the toenail grows.

Other explanations include debris under a partly lifted nail, staining, or a fungal nail change accompanied by thickening, crumbling or yellow-brown colour. Less commonly, melanoma beneath a nail can present as a dark streak or patch. Suspicion is higher when pigment begins without a remembered injury, widens near the cuticle, changes irregularly, or extends onto nearby skin. Appearance alone cannot confirm the cause.

Switch to shoes with enough width and depth for the toes, keep the nail trimmed straight across, and protect it from further impact. If the injury is recent, rest the foot and use a wrapped cool pack for short intervals. Do not burn, drill or pierce the nail at home; this can injure the nail bed and introduce infection.

Photograph the nail in good light and compare the position of the mark as the nail grows. Avoid pulling off a loose nail. Keep it clean, dry and lightly covered if it catches on socks. A clinician can examine the nail and decide whether pressure needs releasing or whether testing for another cause is appropriate.

Arrange prompt care after a strong injury if pain is severe, the toe looks bent, walking is difficult, or a cut will not stop bleeding. Seek urgent assessment for spreading redness, warmth, swelling, pus, fever, numbness, or a toe that becomes cold or unusually pale. People with diabetes, poor circulation, reduced sensation or weakened immunity should get early advice rather than treating a nail injury themselves.

Book a dermatology assessment for a dark mark with no clear injury, pigment that starts at the nail base or spreads onto the surrounding skin, an irregular band that becomes wider, repeated bleeding, or a change that stays fixed instead of advancing with nail growth. A nail that remains painful or repeatedly detaches also deserves review.

Ask whether the pattern fits trapped blood, whether the toe may also be fractured, and how you should protect a loose nail. If there was no injury, ask whether dermoscopy, a nail sample or another test could clarify the cause. Mention when the colour appeared, footwear or activity changes, pain, medicines that affect bleeding, and whether the mark has moved as the nail has grown.