Ingrown toenail or onychocryptosis: how to treat it, when it is infected, and when it requires medical attention

What exactly is an ingrown toenail?

Onychocryptosis occurs when there is a conflict between the nail plate and the skin of the lateral nail fold. The edge of the nail presses against the skin and can end up penetrating it, and the body interprets this aggression as an ongoing trauma. Pain, inflammation, swelling, and redness then appear, and if the process continues, granulation tissue forms around the nail: that red, moist tissue that bleeds easily is an inflammatory response to repeated trauma.

Therefore, although we commonly use the term 'ingrown toenail,' we should not automatically equate it with infection. An inflamed case of onychocryptosis can exist without, initially, any bacterial infection being present.

Why does a nail become ingrown?

There is no single cause; several factors are usually involved. One of the most important is cutting nails incorrectly: when we trim the sides too aggressively in an attempt to achieve a rounded shape, we can leave a small spicule, and as the nail grows back, that tip can dig into the lateral fold.

Other associated factors include footwear that is too narrow, repetitive trauma, sport, hyperhidrosis or excessive sweating, certain anatomical nail shapes, alterations of the periungual folds, nail thickening, onychomycosis in some patients, and individual predisposition.

Can footwear cause an ingrown toenail?

It can clearly contribute. A shoe that is too narrow, short, or pointed compresses the toes and increases the pressure between the nail edge and the skin. This is especially important during sporting activity, running, long walks, or jobs that require standing for many hours. And if the foot also sweats a great deal, the skin surrounding the nail can become macerated and more vulnerable to trauma.

This is why treating an ingrown toenail is not just a matter of looking at the nail: we must also look at the footwear and the mechanical factors acting upon it.

How should we cut our toenails?

This is probably one of the most important preventive measures. Toenails should be cut relatively straight: we should not try to dig deeply into the corners to round them, nor cut them excessively short. The practical recommendation is to allow the nail edge to maintain enough length to advance over the skin rather than penetrating it laterally; both clinical guidelines and NHS health information advise against trimming the corners and recommend making a straight transverse cut.

The classic mistake goes like this: the nail begins to cause discomfort, the person cuts the corner back even further, notices relief for a few days, the nail grows back, and the new spicule embeds itself even more deeply. This is how a vicious cycle begins: pain, cutting laterally, temporary relief, regrowth, and new pain.

What are the symptoms of an ingrown toenail?

At first there may simply be pain when touching the side of the nail, sensitivity when putting on a shoe, slight redness and localised inflammation. As it progresses we may find greater swelling, pain when walking, discharge, bleeding, granulation tissue and, in certain cases, infection. The intensity of the symptoms helps determine what treatment we need.

Are there different grades of onychocryptosis?

Yes. Although various classifications exist, clinically we can understand it in a simple way across three levels.

Grade I: mild inflammation

Pain, sensitivity, slight oedema and redness predominate. There is not yet any significant proliferation of tissue, and here conservative measures can work particularly well.

Grade II: more significant inflammation

Pain increases and discharge, marked inflammation, granulation tissue and a possible secondary infection may appear.

Grade III: advanced or chronic disease

There is a more significant and sustained inflammatory reaction, with hypertrophy of the periungual tissue and prominent granulation tissue. The new 2026 S1 guideline uses precisely a clinical grading classification to guide treatment, reserving surgical techniques — in particular minimally invasive ones with partial action on the matrix — for severe cases or those resistant to conservative treatment.

How can an ingrown toenail be treated at home?

In a mild ingrown toenail, without significant infection, we can start with conservative measures. The first step is to eliminate pressure: wear wide, comfortable shoes with enough room for the toes, and at certain times it may be helpful to use sandals or open footwear. Warm water soaks may also be used to relieve discomfort, keeping the foot clean and dry afterwards.

And something very important: stop continually manipulating the nail. Do not insert scissors, do not try to dig out the corner, do not tear the nail and do not repeatedly cut the painful side, because every manipulation can cause more trauma, more inflammation and a greater risk of infection.

Can I gently lift the edge of the nail?

In mild cases there are conservative techniques aimed precisely at separating the nail from the skin: small cotton wicks, dental floss placed carefully under the edge, taping, splints or small devices that separate the nail edge from the fold, and nail bracing techniques. All of them seek to allow the nail to grow progressively over the fold rather than continuing to penetrate it.

But I do not recommend trying to aggressively insert objects under a nail that is very painful, very inflamed, producing pus or with significant granulation tissue. In those situations, we must first properly assess the toe.

How long does it take for an ingrown toenail to improve?

It depends on the severity. One thing is for the pain to disappear quickly, and quite another is for the nail to have grown enough to clear the lateral fold. Toenails grow slowly, so conservative treatment may need to be maintained for several weeks: a clinical review points to an approximate period of 2 to 12 weeks to allow normal nail growth to pass beyond the edge of the fold.

This explains why 'it no longer hurts' does not necessarily mean 'I can go back to cutting the corner.'

How do I know if an ingrown toenail is infected?

An ingrown toenail produces inflammation on its own, so redness does not automatically mean infection. We should be more concerned when pus appears, along with increasing pain, significant warmth, progressive swelling, spreading redness, bad odour, fever, chills, or general malaise. The NHS recommends a medical assessment when the toe is painful and swollen with discharge of pus, or when systemic symptoms such as fever or chills appear.

Does an ingrown toenail always need an antibiotic?

No, and this is an important point. Onychocryptosis is fundamentally a mechanical and inflammatory problem: if a nail spicule continues to penetrate the skin, administering an antibiotic without resolving the mechanical conflict may not solve the problem. Antibiotics make sense when there is a clinically relevant bacterial infection, but they should not be used automatically for every red or inflamed nail.

Furthermore, the available evidence does not demonstrate any benefit from routinely administering antibiotics around certain procedures, such as phenol matricectomy, when there is no specific infectious indication. Therefore, inflammation is not synonymous with infection, and an ingrown toenail is not synonymous with antibiotics.

What is the red tissue growing beside the nail?

Many people think: 'flesh is growing on me.' What we are generally seeing is granulation tissue: the body is attempting to repair an area subjected to constant trauma. This tissue can be red, moist, highly vascularised, and fragile, bleeding easily, and if the nail continues to press into it, the stimulus maintaining the inflammation remains present.

This is why, in advanced cases, applying creams, antiseptics, or antibiotics is not necessarily enough: we must resolve the mechanical conflict between the nail and the tissue.

When should I see a doctor or podiatrist?

An assessment is advisable when home treatment is not improving the problem, the pain is significant, pus or granulation tissue is present, the nail becomes ingrown repeatedly, the inflammation is progressing, there is significant nail deformity, or walking is becoming painful.

We must also be especially cautious with patients who have diabetes, poor circulation, neuropathy, or immunosuppression. In a person with diabetes, for example, an apparently minor foot injury warrants particular attention due to the higher risk of complications; the NHS specifically advises medical assessment of ingrown toenails in diabetic patients.

What can a doctor do when the nail is severely ingrown?

We don't always need to remove the entire nail; in fact, most of the time it isn't necessary. When the problem is concentrated on one side, we can perform a partial avulsion, which consists of removing only the small lateral strip of nail that is penetrating the tissue. This is usually done under local anaesthesia, and the goal is to eliminate the mechanical element that is sustaining the pain, inflammation, and granulation.

Does the entire nail have to be removed?

Generally, not as a routine matter. Complete extraction may be indicated in certain circumstances, but when the problem affects only one lateral edge, removing just the problematic portion allows most of the nail to be preserved. Furthermore, simply pulling out a nail without addressing the mechanism that causes recurrence does not guarantee that the problem will go away: the nail grows back and may become ingrown again. A recent systematic review and meta-analysis found precisely that isolated nail avulsion carried the highest risk of recurrence among the strategies compared.

What is the nail matrix?

To understand why some nails become ingrown again, we need to know about the nail matrix — the structure that produces most of the nail plate. If we simply remove the lateral edge on a temporary basis, the matrix keeps functioning, the nail grows back, and in certain individuals it can grow back in exactly the same direction. That is why, when ingrown toenail is recurrent, severe, or resistant to treatment, we can act on a small lateral portion of the matrix: this is what is known as partial matricectomy.

What is a matricectomy?

The idea is straightforward: we remove the problematic strip of nail and selectively treat the part of the matrix that produces it, so that this small lateral edge does not grow back. The rest of the matrix remains intact, meaning the rest of the nail continues to grow. The result is usually a slightly narrower nail — not necessarily an absent one.

What is phenolisation?

One classic way to perform a matricectomy is to use phenol. After removing the problematic lateral edge, phenol is applied to the corresponding portion of the matrix to selectively destroy the cells that would otherwise regenerate that strip of nail. For many years this technique has been widely used because it can reduce recurrences compared with simple avulsion; a systematic review of clinical trials found that adding phenolisation to avulsion appeared to lower the risk of recurrence, although the overall quality of the available evidence was low.

Is phenol always the best technique?

Not necessarily, and here we have particularly recent information. A network meta-analysis published in 2026 analyzed 44 studies with 5,068 participants and compared conservative treatments, chemical matricectomy, and various surgical procedures. The authors found that simple avulsion carried the highest risk of recurrence, but the differences among chemical matricectomy, minor surgery, conventional surgery, and conservative treatment were less clear than traditionally thought; chemical matricectomy also showed longer healing times than some modern surgical techniques.

This reminds us of something important: there is no single perfect technique for every patient. The choice depends on severity, recurrences, anatomy, the professional's experience, patient preferences, and clinical characteristics.

Are there alternatives to phenol?

Yes. The matrix can be treated using various surgical, chemical, or electrosurgical methods, and techniques involving radiofrequency, electrocautery, or CO₂ laser, among others, have also been described. But the existence of a more sophisticated technology does not automatically mean it is better: what matters is successfully removing the offending border, preserving as much healthy nail as possible, minimizing complications, and reducing the risk of recurrence.

Does the procedure hurt?

During the procedure, a local anesthetic is administered to the toe, so the goal is for the patient to feel no pain during the intervention. Afterward, there may be discomfort, sensitivity, swelling, and minor bleeding or discharge, depending on the technique used. Recovery time also depends on the procedure: conservative techniques generally produce less pain and a faster recovery, whereas certain matricectomies may require a longer healing period.

Can an ingrown toenail come back after surgery?

Yes. No procedure carries a zero risk of recurrence: it can occur if a small portion of active matrix remains or if predisposing factors persist. For this reason, even after an intervention, we must continue to take care of nail trimming, footwear, trauma, perspiration, and nail diseases. Surgery does not replace prevention.

What is the difference between an ingrown toenail and paronychia?

They are not exactly the same thing. Onychocryptosis describes the penetration or conflict of the nail border with the nail fold, whereas paronychia describes the inflammation of the tissue surrounding the nail, which can have an infectious, irritative, or inflammatory origin, or be caused secondarily by an ingrown toenail. Therefore, an ingrown toenail can cause paronychia, but not all paronychia is caused by an ingrown toenail.

And what if the nail also has a fungal infection?

Onychomycosis can cause thickening, deformity, and changes in the nail plate, and in certain individuals this can contribute to mechanical conflict with the lateral folds. But a yellow, thick, or deformed nail does not automatically mean there is a fungal infection: nail psoriasis, repetitive trauma, nail dystrophies, aging, and other conditions can produce similar changes. That is why, if we suspect onychomycosis and are considering a prolonged treatment, it may be advisable to confirm the diagnosis.

What should you not do with an ingrown toenail?

You should not repeatedly cut the corners, pull at the side of the nail, insert sharp instruments underneath it, use antibiotics on your own, continue wearing shoes that compress the toe, or ignore pus, progressive pain, or fever — nor should you attempt a little 'home surgery.' Many ingrown toenails that begin as a relatively simple problem worsen precisely because of repeated manipulation.

How can I prevent it from coming back?

Prevention starts with something very simple: trimming the nail properly, keeping the cut relatively straight, without cutting it too short or digging into the corners. Add to that wearing sufficiently wide footwear, keeping the feet clean and dry, and treating hyperhidrosis, onychomycosis, or mechanical abnormalities when appropriate.

And if a nail becomes ingrown repeatedly, we must stop treating only each individual episode and ask ourselves: why does this nail keep becoming ingrown?

When is an ingrown toenail an emergency?

Most are not. But a more prompt assessment is warranted when there is fever, a progressing infection, redness spreading across the toe or foot, increasing severe pain, necrosis or a significant change in color, or a complicated wound in a patient with diabetes, vascular disease, immunosuppression, or neuropathy. In these patients, I do not recommend 'waiting a few days to see what happens.'