When to Seek Treatment for Toenail Trauma

Subungual Hematoma

Fresh subungual haematoma
Credit: Braegel/Wikimedia Commons

If you stub your toe or drop something heavy on your feet, you may develop subungual hematoma, which is blood trapped beneath the toenail. This gives the toenail a red, black, or purple discoloration. It is often called black toenail for that reason.

Subungual hematoma is usually caused by blunt trauma from a heavy object or chronic friction from rubbing against the shoe.

 Acute trauma isn't necessarily a cause. People who do a lot of walking or running are more prone to subungual hematomas because of increased shoe friction. Marathon runners and hikers are very familiar with this malady.

Symptoms of Toenail Trauma

A subungual hematoma can range from a small spot under the nail to a large area of discoloration. Depending on the amount of blood beneath the nail, the nail may come loose. But often the nail does stay intact, and the blood fades as the nail grows out. If the subungual hematoma is large and causing pain, medical treatment will be needed to relieve pressure under the nail.

When to See the Doctor for a Toenail Injury

It's time to go from self-care to seeing a medical professional if any of these six conditions apply in your case.

  • If there is blunt trauma to the toenail. For example, if a heavy object has been dropped on the toe, it is best to seek treatment to rule out a fracture and treat any wound beneath the nail bed.
  • If toenail trauma leads to severe swelling, pain, or redness of the toe
  • If there is any discharge from under the toenail
  • If the nail becomes loose
  • If you have neuropathy, diabetes, peripheral arterial disease, or any condition that affects healing or circulation
  • If the discoloration appears as a linear streak or a stripe going with the length of the nail. Although a streak of pigment is often normal, in some cases it may be a sign of the skin cancer melanoma.

    If the nail is raised, the doctor may relieve the pressure by drilling a hole through the nail. If it is loose, the nail may be trimmed or even reattached to protect the nail bed while the nail is regrowing.

    Changes to the Toenails Due to Trauma

    Nail trauma may not always lead to bleeding beneath the nail but to other predictable changes. These changes may occur due to chronic rubbing against the shoe or in response to irritation from a fungal or bacterial infection. Some of the most common changes are:

    • Nail thickening: This is caused by damage to the nail's growth center, called the nail matrix. It responds by producing a thicker nail.
    • Nail dystrophy: You may see permanent nail changes such as splitting or a decrease in size.
    • Nail avulsion: Sometimes the entire nail or a portion of it becomes loose or falls off. This is often a temporary condition and the nail will regrow over the course of a couple of months.
    • Permanent nail loss: This can happen due to damage to the nail matrix. The toenail may not regrow.

    Source:

    Usatine RP, Smith MA, Chumley HS, Mayeaux EJ, Jr. Chapter 196. Subungual Hematoma. In: Usatine RP, Smith MA, Chumley HS, Mayeaux EJ, Jr.. eds. The Color Atlas of Family Medicine, 2eNew York, NY: McGraw-Hill; 2013.