Causes and Risk Factors of Ingrown Toenails

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Ingrown toenails are a common foot condition. It happens when a toenail's edge grows into the skin, causing redness, swelling, and pain. If left untreated, an ingrown toenail can become infected and cause serious issues.

There are several causes and risk factors for developing an ingrown toenail. The two most common causes are wearing shoes that are too tight and cutting toenails too short or with rounded edges.

This article will cover common causes and risk factors of ingrown toenails. It will discuss how heredity and lifestyle may also play a role in the condition.

Cutting toenails

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Common Causes

There are many causes of ingrown toenails. The most common causes are shoes that don't fit properly and poorly trimmed toenails.

When shoes are worn too tightly, extra pressure is placed on the toenail. That pressure can cause the nail to grow into the skin and become ingrown.

Toenails that aren't trimmed correctly can also cause an ingrown toenail. Toenails trimmed too short or toenails with rounded edges can grow into the skin and become an ingrown toenail.

Other causes of ingrown toenails include:

  • Stubbing a toe or toe injury
  • Toenails that are too large for the toe
  • Foot or toe deformities
  • Repetitive sports activities (such as kicking a soccer ball)
  • Obesity
  • Wet or sweaty feet
  • Taking certain cancer medications
  • Pincer toenails (nails that grow tube-shaped)


Genetics usually do not play a role in ingrown toenails. However, some people can inherit a tendency for ingrown toenails.

Pincer toenails are a rare nail deformity that occurs in 0.9% of the population. It's characterized by thickening of the nail and the nail edges growing toward each other, forming a half tube shape.

The cause of pincer nail growth is not completely understood, but it may either be hereditary (passed down from one's parents) or acquired. Conditions that can lead to acquired pincer toenails are:

  • Renal failure (kidney failure)
  • Kawasaki disease (acute inflammatory condition of the heart and blood vessels)
  • Gastrointestinal (GI) cancers
  • Amyotrophic lateral sclerosis (ALS) (progressive neurological disease)
  • Lupus (autoimmune disease)

A 2020 study reported that when these conditions were well-controlled, the pincer nail went away.


A toenail is more likely to become ingrown if you have a condition that causes water retention in your feet. Water retention can be due to cardiovascular conditions, including heart failure, kidney failure, or chronic venous insufficiency.

Lifestyle Risk Factors

A few lifestyle risk factors can increase the likelihood of developing an ingrown toenail. These factors may be modifiable or unmodifiable. Modifiable factors are changes a person can make to decrease their risk. Unmodifiable factors that can contribute to prevalence of this condition are ones that cannot be changed, such as age, gender, or ethnicity.

Some lifestyle risk factors include:

  • Being a teenager or young adult: People in this age range tend to have sweatier feet due to hormonal changes.
  • Being older: Older people may have a harder time taking care of their feet or seeing changes in their feet that can lead to an ingrown toenail.
  • Sports: Playing sports that involve repetitive kicking and running can injure the toenails.
  • Certain health conditions: Conditions that decrease blood flow to the feet, such as diabetes, can cause ingrown nails on the feet.


An ingrown toenail is when the edges of the nail grow into the skin. This causes redness, swelling, and pain. Ingrown toenails can be caused by many factors, including shoes that are too tight, trimming toenails too short, or participating in sports that involve kicking or running. There are also risk factors such as diabetes and age that play into developing an ingrown toenail.

A Word From Verywell

An ingrown toenail may sound minor, but it can turn into something serious if left untreated. A mild ingrown toenail can be treated at home, but moderate or severe ingrown nails need to be treated by a healthcare provider. If left untreated, the toenail can break into the skin, which can allow bacteria in and cause an infection. If you have any questions or are unsure how to treat your ingrown toenail, don't hesitate to reach out to your healthcare provider.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Ingrown toenail.

  2. Nemours Children's Health. Ingrown toenails.

  3. Institute for Quality and Efficiency in Health Care (IQWiG). Ingrown Toenail: Overview.

  4. Huang C, Huang R, Yu M, et al. Pincer nail deformity: clinical characteristics, causes, and managementsBiomed Res Int. 2020;2020:2939850. doi:10.1155/2020/2939850

By Patty Weasler, RN, BSN
Patty is a registered nurse with over a decade of experience in pediatric critical care. Her passion is writing health and wellness content that anyone can understand and use.