An ingrown toenail, medically known as onychocryptosis, occurs when the edge of the toenail presses into or penetrates the surrounding skin. This repeated mechanical irritation causes inflammation, pain and swelling. If the skin becomes damaged, bacteria can enter the area and produce a secondary infection.
Although an ingrown toenail can affect any toe, it most commonly occurs along one or both sides of the big toenail. The condition ranges from mild irritation to severe, long-standing disease that may significantly interfere with daily life.
Many people imagine that the nail is "growing into" the skin. While this description is useful, it is not always anatomically accurate. In many patients, the nail itself grows normally, but the surrounding skin folds become compressed against the nail edge. In others, the nail is naturally more curved than average, causing the edge to continually traumatise the skin as it grows forward. In both situations, the result is the same—ongoing irritation and inflammation.
Initially, patients usually notice tenderness when pressure is applied to the side of the nail. Shoes become uncomfortable, touching the toe becomes painful and activities such as running or prolonged walking may become increasingly difficult. At this stage, the skin may appear only mildly swollen and red.
As the condition progresses, the inflammation often becomes more pronounced. The skin may begin to bleed easily, produce discharge or develop excessive granulation tissue—sometimes referred to as "proud flesh." This tissue forms because the body continually attempts to heal an area that is being repeatedly injured by the sharp nail edge. Although its appearance can be alarming, granulation tissue is a sign of persistent irritation rather than an indication that the problem has become untreatable.
One of the most important concepts to understand is that an ingrown toenail is primarily a mechanical condition. Infection is often secondary. This distinction explains why repeated antibiotics frequently provide only temporary improvement. While antibiotics may reduce bacterial infection, they do not remove the nail edge that continues to injure the surrounding skin. Unless the underlying cause is corrected, symptoms commonly recur.
Not every painful toenail is an ingrown toenail. Conditions such as traumatic nail injuries, fungal nail disease, chronic paronychia, subungual exostosis, benign or malignant tumours of the nail unit and certain inflammatory skin disorders can all mimic the symptoms of an ingrown toenail. This highlights the importance of careful clinical assessment before treatment is recommended.
Fortunately, most ingrown toenails are highly treatable. Depending on the stage of the condition, management may range from conservative measures through to minor surgical procedures designed to permanently prevent recurrence. The choice of treatment depends on the severity of the condition, the anatomy of the nail, whether infection is present, whether previous procedures have been performed and the patient's individual goals.
Throughout the remainder of this handbook, you will learn that successful treatment is rarely about simply removing part of the nail. Instead, it is about understanding why the nail became ingrown, selecting the most appropriate treatment and aiming to achieve a long-term solution rather than repeated temporary relief.
Evidence Update
Modern clinical guidelines recognise ingrown toenails as a mechanical disorder of the nail unit rather than simply an infection. Current evidence supports treating the underlying cause, with procedures that permanently address the offending portion of the nail generally producing lower recurrence rates than temporary nail removal alone when permanent treatment is indicated.
Patient Tip
If your ingrown toenail keeps returning after repeated antibiotics, it is worth asking whether the underlying nail edge has actually been treated. Antibiotics may control infection, but they do not change the shape or growth pattern of the nail.