Common causes of toenail problems include nail fungus, an ingrown toenail and toenail trauma. Toenails are subject to stress from different sources, which can lead to toenail issues, according to About.com.
Toenail fungus is an infection of the nail and underlying skin and is commonly caused by the same type of bacteria that causes athlete's foot. Medically referred to as onychomycosis, this condition is slow growing, and people who are susceptible to athlete's foot can also have a higher risk for developing toenail infections, About.com reports. This infection causes a white, yellow or brown discoloration of the nail. It also causes the nail to thicken over time and can be difficult to treat since it is located under the toenail.
Ingrown toenails usually affect the big toe. This condition happens when the edge of the nail grows into the skin, explains About.com. Symptoms include redness, swelling, pain at the location and discharge. Shoes or socks that don't fit well or abnormal toe shapes are some contributing factors to this condition.
Toenail trauma is caused by an injury to the toe's nail growth center. This can cause changes in the toenail such as bruising, nail thickening and nail loss, states About.com. Toenail trauma can also induce a bacterial or fungal infection.