There are several reasons your toe nails may appear black or darkened. Some are harmless and temporary, while others need professional attention.
1. Trauma or Injury
Repeated pressure from shoes, running, or sports can damage the nail bed, causing small blood vessels underneath to burst. The trapped blood (called a subungual haematoma) turns the nail black or purple.
If the blackened area covers more than half the nail or you experience pain or swelling, book an appointment with one of our sports podiatrists for assessment.
2. Fungal Nail Infection
A fungal infection can cause discolouration, thickening, and brittleness. Although it often begins yellow or white, in advanced stages it can darken the nail.
Learn more about treatment options on our fungal nail therapy page.
3. Tight or Poorly Fitted Footwear
Shoes that are too small or narrow compress the toes and repeatedly hit the nail, leading to bruising and blackening over time.
Our custom orthotics can help reduce pressure and improve foot alignment to prevent recurrence.
4. Underlying Health Conditions
Sometimes blackened toe nails are linked to conditions like diabetes, circulatory issues, or melanoma (a rare but serious cause). It’s essential to have any persistent nail discolouration checked by a podiatrist or GP.
Symptoms to Watch Out For
Blackened nails can vary in appearance depending on the cause. Common signs include:
- Dark brown, purple, or black patches under the nail
- Thickened or lifted nails
- Pain, pressure, or throbbing
- Foul odour or crumbly texture (in fungal cases)
- Changes that persist or spread to other nails
If the nail looks detached, oozes fluid, or becomes painful, see a podiatrist promptly. Leaving the issue untreated can lead to infection or permanent nail damage.
Treatment Options for Blackened Toe Nails
Treatment depends on the cause and severity.
Minor Trauma
If caused by mild trauma, the discolouration will usually grow out with the nail over several months. Keep the area clean and wear roomy footwear to prevent further irritation.
Severe Trauma or Blood Under the Nail
For large or painful bruises, your podiatrist may release trapped blood to relieve pressure and pain. Avoid trying to do this at home — it risks infection.
Fungal Infection Treatment
Depending on the type and severity, we may recommend:
- Topical antifungal treatments
- Laser therapy
- Oral medication (for persistent cases)
Visit our nail fungus treatment page to learn how we help patients restore clear, healthy nails.
Nail Debridement or Removal
In some cases, the damaged nail may need partial or full removal. Our medical pedicure and podiatry nail care services ensure the procedure is safe, sterile, and pain-free.
How to Prevent Toe Nail Blackening
A few simple habits can go a long way toward keeping your nails healthy:
- Choose properly fitted shoes.
Ensure there’s a thumb’s width of space between your longest toe and the shoe tip. - Keep nails trimmed and clean.
Cut straight across and file gently to prevent ingrown nails and pressure. - Wear moisture-wicking socks.
This helps reduce fungal growth, especially during sports. - Rotate your footwear.
Allow shoes to dry fully between wears. - Check your feet regularly.
Especially if you’re diabetic — early intervention is key to avoiding complications.
Learn more on our diabetic foot care page.
When to See a Podiatrist
Book a podiatry appointment if:
- The nail is painful, swollen, or oozing
- The black area doesn’t grow out after a few months
- Multiple nails are affected
- You have diabetes or poor circulation
- The nail shape or texture changes suddenly
Our team can diagnose the exact cause using clinical assessment and, if necessary, imaging or lab testing. Early treatment prevents chronic damage and keeps you active without discomfort.
Professional Nail Care at ModPod Podiatry
At ModPod, we combine advanced podiatric medicine with a holistic approach to foot health. Whether your blackened toe nail stems from running, infection, or an injury, we can identify the cause and develop a personalised treatment plan.
Our Sydney clinics — including Mosman, CBD, Rose Bay, and Dee Why — provide expert care in:
Book an Appointment
If you’ve noticed toe nails blackening, don’t ignore it — the sooner you address the issue, the better your outcome. Book online or call your nearest ModPod Podiatry clinic to schedule an assessment today.
