What Causes Ingrown Toenail?

Several conditions can cause ingrown toenails:  improper trimming, injury, genetics, and shoe choice to name a few.  It’s important to understand the likely cause of your nail condition to understand your best treatment options.

Improper Trimming Of The Nails

Classic Ingrown Toenail

Illustration Of A Classic Ingrown Toenail (Generally Caused By Improper Trimming or Injury)

Improper trimming is considered the cause of most truly ingrown nails, the kind that result in puncturing of the skin.  That’s why a step-by-step guide to trimming your toenails seems to be the go to “fix” for the problem.  And unless this is the very first website you’ve visited looking for answers, you’ve surely noticed this.

See the blog post “Are Your Trimmers Causing Ingrown Toenails?” for an explanation of how improper trimming causes the nail to become ingrown as well as instructions/tips on toenail trimming.

The good news is that ingrown nails caused by improper trimming are usually the easiest to remedy and the easiest to prevent with the right knowledge.


Injuries such as dropping something on your toe or repeated trauma such as that incurred from kicking a soccer ball or running with ill fitting shoes can sometimes be the culprit behind your toenail pain by causing a piece of the nail to be jammed into the skin. When this happens, the skin around or in front of the nail may also become inflamed and block the “growth path” of the nail.  As the nail grows, this type of ingrown nail may mimic those caused by improper trimming.

Genetics And Shoes/Hosiery

Curved Ingrown Toenail

Illustration Of Curved Ingrown Toenail (Generally Caused By Heredity Or Tight Hosiery/Shoes)

Some people have nails that are naturally quite curved.  Some people wear shoes or hosiery that are too tight.  Some people have both.

If you fall into the category of people with naturally incurvated nails, the deck might be stacked against you but you aren’t out of luck.  If you fall into one of the other two categories, STOP!  :-)  I know, it’s easier said than done.

Most people wear shoes anywhere fro 10 to 14 hours per day.  When you throw socks into the equation, that time frame can dramatically increase.  Let’s picture what that pressure (though seemingly mild) does to a toenail.  You have probably heard the phrase “taking the path of least resistance”.  That is exactly what your toenail will do when it bumps up against pressure from a shoe or sock.  As your nail meets the prolonged and repeated pressure of the shoe or sock, it eventually learns to grow in a different direction…down into your toe!

These are the conditions that result most frequently in the highly curved ingrown toenails.  Depending on the natural shape of the nail and how long the condition has existed, the excessive curve may be only in the front portion of the nail or may start at the root and extend the entire length of the nail.  Additionally, the amount and duration of the pressure on the nail will influence the degree of curvature.