Why Is a New Nail Growing Under the Old One? Causes, Symptoms & What to Do

Have you noticed a second nail forming underneath your current toenail or fingernail? While it can be alarming at first, this phenomenon is more common than you might think. Whether it’s your big toe or index finger, the appearance of a new nail growing under the old one may be your body’s way of responding to injury, infection, or a nail disorder.

In this guide, we’ll explore why this happens, what it might mean for your nail health, and how to handle it—especially if pain is involved.

What Does It Mean When a New Nail Grows Under the Old One?

When a new nail begins forming beneath an existing one, it usually signals that the old nail is no longer viable. This process, known as nail plate detachment or onycholysis, can happen for a variety of reasons. The body responds by growing a fresh nail underneath to eventually replace the damaged one.

Common causes include:

• Trauma or Injury: Stubbing your toe or slamming your finger in a door can lift the nail from the bed, triggering new nail growth beneath the old one.

• Fungal Infections: Infections like athlete’s foot or onychomycosis can cause the nail to thicken, lift, or become discolored, often prompting the growth of a new nail.

• Psoriasis or Eczema: Autoimmune skin conditions can disrupt healthy nail development, sometimes leading to layered nail growth.

• Poor Foot Hygiene or Tight Shoes: Especially common in athletes or those who wear ill-fitting footwear, repetitive pressure can damage the nail matrix and cause irregular growth patterns.

Is It Painful?

It can be, especially with toenails. A new toenail growing under the old one often causes pain due to added pressure and inflammation. You might feel:

• Throbbing or tenderness in the toe

• Pain when wearing closed-toe shoes

• Discomfort during activities like walking or running

In contrast, a new fingernail growing under the old one may not be as painful but can still feel tight or sensitive, especially when using your hands.

Signs You’re Growing a New Nail

Look for the following indicators:

• A clear or milky edge peeking out from under the old nail

• Lifting or loosening of the current nail

• Unusual thickness or ridges in the nail

• Discoloration—usually yellow, white, or brown

• Pain or swelling in the nail bed

If you notice any of these signs, it may mean the body has already started the process of replacing the old nail.

Should You Remove the Old Nail?

No, do not attempt to remove it yourself. Pulling off the old nail can introduce infection and delay healing. Instead:

• Keep the area clean and dry

• Trim the old nail carefully without forcing it

• Wear open-toe or loose-fitting shoes if it’s a toenail

• Use bandages or protective coverings if necessary

If the old nail is loose and causing discomfort, see a podiatrist or dermatologist for safe removal or further treatment.

When to See a Doctor

You should consult a healthcare provider if:

• The pain is severe or worsening

• There’s pus, foul odor, or signs of infection

• The new nail is growing abnormally or appears discolored

• You have underlying conditions like diabetes or immune disorders

Medical professionals can determine if the issue is fungal, traumatic, or related to other health conditions—and recommend the right treatment.

How to Support Healthy Nail Regrowth

Whether you're dealing with a toenail or fingernail, here’s how to promote smoother healing:

• Biotin supplements may help strengthen new nail growth

• Moisturize daily to reduce brittleness

• Protect the nail bed during sports or physical activity

• Practice good nail hygiene, including proper trimming

• Treat infections early with antifungal creams if needed

Most importantly, be patient. Fingernails can take up to 6 months to regrow completely, while toenails may take 12–18 months.

Final Thoughts

A new nail growing under the old one may seem unusual, but it’s often a natural healing response to damage or infection. Understanding the root cause, taking proper care, and seeking help when necessary are key to keeping your nails healthy—and pain-free.