Damaged nail
You may notice that your toenail is sensitive, painful or has turned a dark colour after exercising, walking or bumping your toe. Sometimes the nail feels thick or there is pressure under the nail. The nail may also become partially detached.
A damaged toenail is often caused by a knock or by prolonged pressure on the toes. For example, this can be caused by sport or shoes that are too tight. The symptoms can be troublesome when walking, playing sport or wearing shoes.

What is it?
A damaged nail is also known as nail trauma. This occurs when the toenail is damaged by a blow or prolonged pressure on the toe.
The damage may cause the nail to discolour, become sensitive or come away. Sometimes pressure or a bruise may also develop under the nail.