Many people, especially those who run or jog on a consistent basis, have experienced black toenails. Whether the top of the shoe constantly bangs against the nail or the toe slams into the front end of the shoe, the condition involves bruising, bleeding, or blistering beneath the nail due to repeated trauma.
However, not all black toenails are a result from running. In some circumstances, a dark nail could mean a serious health condition.
The following are five common causes of black toenails, as well as which types are considered harmful or harmless:
- Repetitive trauma – Considered the most common cause for black nails, it occurs due to running or wearing any type of uncomfortable and ill-fitting footwear. In mild cases, the black nail will simply grow out without treatment. In serious cases, the nail can detach from the nail plate, requiring a long time for a new nail to grow.
- Subungual Hematoma – Dropping something heavy onto your toe can burst the vessels under your nail bed, resulting in blood pooling underneath. The blood buildup typically causes a painful, throbbing sensation which requires the pricking of a tiny needle through the nail to drain out the blood by a doctor.
- Fungal infections – Athlete’s foot, for example, can spread to your toenails, turning them shades of yellow, green, brown, blue, purple, and black. It is important to visit your doctor immediately, so he or she can clip and biopsy a portion of your nail to determine a diagnosis. Mild cases can be cured using topical medications while more aggressive fungus may need oral medication or laser treatment.
- Skin tone – The pigmentation in the skin underneath the toenails can change over time. While this is often harmless, get them checked by your doctor to be on the safe side.
- Skin cancer – Did you know that melanoma can grow underneath your nail bed on the nail, resulting in hyperpigmentation of the skin? If you haven’t experienced any trauma to your nail and it is slowly starting to change color, even beyond your nail, you must get it checked immediately.