Why Does One Toenail Grow Sideways Into the Skin? (Onychocryptosis)

When one toenail seems to grow sideways into the surrounding skin, the issue is often an ingrown toenail, medically known as onychocryptosis. It develops when the corner or side of the nail presses into or penetrates the nearby nail fold, leading to tenderness, redness, swelling, or irritation.

It can affect only one nail because nail shape, prior injury, footwear pressure, and trimming habits may differ from toe to toe. The big toe is affected most often, but any toenail can become ingrown. Mild cases may respond to conservative care, while persistent, painful, or inflamed nails deserve professional evaluation.

Quick answer

• A naturally curved or unusually wide nail may press into the skin as it grows.
• Cutting the nail too short or rounding its corners can encourage the edge to grow into the nail fold.
• Tight shoes, repetitive pressure, and past toe injuries may alter how one nail grows.
• Redness, swelling, drainage, or worsening pain may indicate significant inflammation or infection.
• A dermatologist or other qualified clinician can examine the nail and discuss appropriate options.

What does onychocryptosis mean?

Onychocryptosis is the medical term for an ingrown nail. Instead of extending forward over the end of the toe, one side or corner of the nail pushes into the soft skin beside it. The skin may react with tenderness, swelling, redness, and extra tissue around the nail edge.

The nail does not always grow in a dramatic sideways direction. Sometimes the nail plate is only slightly curved, but pressure from shoes or surrounding skin causes the edge to become embedded. In other cases, the edge may form a sharp point after trimming and begin digging into the nail fold as the nail grows.

Why can it happen to only one toenail?

Each toenail has its own shape, growth pattern, and history. One toe may be more crowded inside a shoe, may have experienced a prior injury, or may have a nail that is naturally more curved than the others. Even small anatomical differences can make one nail more likely to press into the surrounding skin.

A previous impact, such as stubbing the toe or repeatedly striking the front of a running shoe, may also affect the nail-producing tissue. The resulting nail can grow with a ridge, curve, thickened area, or altered direction. These changes are not always obvious until the nail edge begins causing discomfort.

Common causes and triggers

• Rounded trimming: Cutting down into the corners can leave a pointed edge that grows into the skin.
• Cutting too short: The surrounding skin may rise over the nail edge as the nail begins growing back.
• Tight footwear: Narrow shoes or shoes that press against the toes can push the nail and skin together.
• Naturally curved nails: Some nails curve inward more sharply because of inherited nail shape.
• Repetitive pressure: Running, kicking sports, long walks, or occupational footwear may repeatedly stress one toe.
• Past trauma: Stubbing, dropping an object on the toe, or losing a nail may change later growth.
• Thickened or irregular nails: Changes in nail texture or shape may make proper trimming more difficult.
• Surrounding swelling: Inflamed skin around the nail can increase pressure against the nail edge.

What you can do at home

For a mildly tender nail without significant swelling, drainage, or spreading redness, conservative steps may reduce pressure and irritation. Wear shoes with a roomy toe box or open-toed footwear when appropriate. Keep the foot clean and dry, and avoid repeatedly pressing, picking, or digging beneath the nail.

Warm water soaks may help soothe the area and soften the surrounding skin. Afterward, dry the toe carefully. A small amount of petroleum jelly and a clean bandage may help protect irritated skin from friction.

Allow the nail to grow rather than cutting deeply into the painful corner. When it is ready to be trimmed, cut it straight across and avoid tapering the sides. Do not attempt to remove a deeply embedded nail edge with sharp tools. Home cutting can worsen inflammation, cause bleeding, or introduce bacteria.

People with diabetes, reduced circulation, nerve damage, immune suppression, or a history of poor wound healing should seek individualized medical guidance rather than managing a painful foot problem independently.

Professional options

A clinician can examine whether the discomfort is caused by an ingrown edge, nail trauma, thickening, inflammation, infection, or another condition affecting the nail unit. The appropriate approach depends on how deeply the nail is embedded, whether the problem keeps returning, and whether the surrounding skin is inflamed.

For a mild case, professional care may focus on reducing pressure and guiding the nail edge above the skin. More persistent cases may require numbing the toe and removing a narrow portion of the affected nail edge. When the same side repeatedly becomes ingrown, a clinician may discuss a procedure intended to limit regrowth from that specific section of the nail-producing tissue.

These procedures are not appropriate for every person or every nail concern. Your clinician can help you understand the potential benefits, limitations, aftercare, and recurrence risk based on an in-person evaluation.

When to see a dermatologist

Schedule an evaluation when the nail remains painful despite conservative care, repeatedly grows into the same area, or has become difficult to trim safely. Professional assessment is also important when the nail is unusually thick, discolored, distorted, separating from the nail bed, or changing without an obvious explanation.

Seek prompt medical care if you notice:

• Pus, drainage, or an unpleasant odor
• Increasing warmth, swelling, or throbbing pain
• Redness that appears to be spreading beyond the nail fold
• Bleeding or overgrown tissue along the nail edge
• Fever or feeling generally unwell
• A foot wound when you have diabetes, poor circulation, or reduced sensation

These findings can be associated with infection or another complication and should not be ignored.

Frequently asked questions

Can an ingrown toenail correct itself?

A very mild nail edge may improve as the nail grows forward and pressure is reduced. However, a deeply embedded, repeatedly painful, or inflamed nail may continue causing symptoms without professional care.

Should I cut out the painful corner?

Digging into the corner can leave a sharper nail fragment, injure the skin, and make the problem more difficult to manage. It is generally safer to let the nail grow and have a clinician evaluate an embedded edge.

Why does the same toenail keep becoming ingrown?

Recurring problems may be related to the nail’s natural curvature, repeated pressure, trimming technique, previous trauma, or changes in the nail-producing tissue. An examination can help identify contributing factors.

Can tight shoes cause one nail to grow sideways?

Tight or narrow footwear may place more pressure on one toe than the others, especially when the foot slides forward or the toes are crowded. This pressure can push the nail edge into the surrounding skin.

Is a sideways-growing toenail always an ingrown nail?

No. Nail trauma, thickening, infection, and structural changes can also alter the nail’s direction or appearance. A dermatologist can evaluate the nail when the cause is unclear.

How should toenails be trimmed?

Trim toenails straight across, leave a small visible edge, and avoid cutting deeply down the sides. Use clean tools and do not trim so closely that the surrounding skin rises over the nail.

This article is for educational purposes and is not medical advice. For diagnosis and personalized treatment, please book an appointment with a board-certified dermatologist.

Sources & further reading

• Mayo Clinic – Ingrown toenails: Symptoms and causes
• MedlinePlus (NIH) – Ingrown toenail
• Cleveland Clinic – Ingrown Toenails: Signs, Causes, Treatment and Prevention