Doctor's Notes on Ingrown Toenails (Onychocryptosis, Unguis Incarnatus)
Ingrown toenails, medically known as onychocryptosis, are caused by a toenail growing into the surrounding nail fold. Some conditions that may predispose to the development of ingrown toenails include injuries, poor foot hygiene, deformities of the toes or feet, and improper footwear. Ingrown toenails are most commonly seen in the big toe and are a relatively common problem.
Associated signs and symptoms include redness, pain, and swelling of the affected toe. In many cases, an ingrown toenail may become infected. In the case of an infection, drainage of yellowish pus may occur from the site. Other symptoms associated with ingrown toenails can include limping or gait disturbances if the pain interferes with walking and the development of scar tissue at the site.
Ingrown Toenails (Onychocryptosis, Unguis Incarnatus) Symptoms
An ingrown toenail is a common disorder that most often affects the outer edges of the nail of the big toe (hallux) most frequently. However, the nail on any toe can become ingrown. The most common signs and symptoms are pain, redness, and swelling at the margins of a toenail.
- Early in the course of an ingrown toenail, the end of the toe becomes reddened and painful with mild swelling. There is no pus or drainage. It may feel warm to the touch, but you will not have a fever.
- Later, extra skin and tissue will grow around the sharp point of the nail. A yellowish drainage may begin. This is the body's response to the trauma of a nail irritating the skin and is not necessarily an infection.
- Sometimes an infection develops. In this case, the swelling will become worse, and there may be white- or yellow-colored drainage (pus) from the area. A lighter-colored area of the skin may be surrounded by red skin. A fever may develop, although this is unusual.
Ingrown Toenails (Onychocryptosis, Unguis Incarnatus) Causes
- Tight-fitting shoes or high heels cause the toes to be compressed together and pressure the nail to grow abnormally.
- Improper trimming of toenails can cause the corners of the nail to dig into the skin. Nails should be trimmed straight across, not rounded.
- Disorders such as fungal infections of the nail can cause a thickened or widened toenail to develop.
- Either an acute injury near the nail or any trauma that causes the nail to be damaged repetitively (such as playing soccer) can also cause an ingrown nail.
- If a member of your family has an ingrown toenail, then you are more likely to develop one, too. Some people's nails are normally more rounded than others or the underlying bone can be more "upturned," which increases the chance of developing ingrown nails.
An ingrown toenail occurs either when the nail grows into surrounding skin or the skin grows over the edge of the nail. Ingrown toenails commonly occur as a result of trimming toenails with tapered edges instead of cutting nails straight across. As the nail begins to grow, it may curl under and dig into the skin or the skin may infringe upon the nail. The skin around an ingrown toenail may be red and swollen, causing pain. Severe cases may ooze pus.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.