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Discoloured Toenail

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It’s one thing when you change the nail polish colour on your toenails, but if your toenails naturally change colour, it could indicate a problem brewing behind the nail bed.  

A healthy toenail is usually clear and partially translucent (i.e.: the colour of your skin tone – more or less).  This can change to black, yellow, brown, green or blue, depending on what precisely is going on. If you have a discoloured toenail (also known as “chromonychia”), you can see a foot specialist at our clinic to find out the underlying cause and get the appropriate treatment.


There are many other ways toenail discolouration may present itself, and sometimes the changes may be ambiguous or not immediately obvious. A discoloured toenail may be:

  • Red
  • Black
  • Purple
  • Yellow
  • Brown
  • Green
  • Blue
  • Yellow-Brown spots
  • White streaks
  • White on the bottom/pink on top
  • White

This list is not exhaustive.

If you notice any changes to the colour, pattern, thickness, shape, texture or consistency of your toenails, it is best to see a chiropodist for guidance.


Why Is My Toenail Discoloured?

The precise colour of a discoloured toenail is a barometer for what is going on behind the nail.  The following is our “colour guide” to discoloured toenails and their causes:

Red/Black/Purple Toenail:  In most cases a black toenail is caused by trauma to the toenail. It may start out as a reddish-purple colour and then gradually change to black. This can be from dropping something on your toe, or repetitive minor traumas such as exercising in shoes that are too small. The black colour typically comes from bruising or blood beneath the nail.  

Yellow/Brown Toenail:  Toenail fungus (also called “onychomycosis”) is the primary cause of yellowing toenails.  Fungus is also one of the most common causes of toenail discolouration.  

Thicker nails can also make your toenails yellow due to the disruption of light passage through the nail.

Green Toenail:  Green nail syndrome (GNS) is a toenail infection caused by bacteria (as opposed to fungus). A bacterial infection is usually confined to a single toenail and often follows some sort of trauma that left an opening in the nailbed, through which bacteria entered.

Blue Toenail:  If you notice a small circular blue mole behind your toenail, it may be something called a blue nevus.  A blue nevus is usually benign and not a cause for concern; however, in very rare cases, it can become cancerous.  If you notice such a discolouration behind your nail, it is best to seek medical attention just to be safe.  

Yellow-Brown Spots:  This can indicate an auto-immune skin-related disease called psoriasis.

White on the bottom half; Pink on the top:  This can indicate kidney problems.

White:  This can indicate liver problems. 

These are just some of the many variations of toenail discolouration.  For more information about the many forms of toenail discolouration and their causes, you can check out this guide:


How Do I Treat Discoloured Toenails?

Treatment for toenail discolouration will vary depending on what is causing it.

To find out what’s causing your discoloured toenail and how to treat it, you can schedule a nail care appointment with one of our foot specialists (chiropodists) using the booking form below, or call us at 416-769-3338 (FEET).  

Click here to learn more about our nail care and treatment services.

Risk Factors

What Causes Toenail Discolouration?

Risk factors for green toenails due to infection include:

  • Open sores around the toenail
  • Trauma or injury that causes a crack or break in the skin by or behind the toenail.  

Risk factors for yellow toenails include:

  • Brittle or cracked toenails
  • Exercising in ill-fitting athletic shoes
  • Walking barefoot in communal swimming pools, gyms, yoga studios, showers, and locker rooms
  • An existing athlete’s foot infection
  • Reduced circulation in the feet due to peripheral vascular disease or diabetes

Risk factors for black/purple toenails due to bruising include:

  • Wearing open-toed shoes
  • Wearing running shoes that are too small – your feet can swell a full shoe size over the course of a long run or walk
  • Running shoes that are too big and allow your toes to shift forward and bang the front of toe box
  • Trauma to the toenail

If you need assistance choosing athletic shoes, our staff can assist you in selecting footwear that fits correctly. Drop-in shoe fittings are available during clinic hours Monday-Saturday and alternating Sundays. This is a complimentary service; No appointment required.


How Do I Prevent Toenail Discolouration?

Here are several things you can do to prevent toenail discoloration:

  • If you have dry, brittle toenails, moisturize your toenails daily with a specialized cream
  • Wear close-toed shoes with a roomy toe box to prevent nail trauma (but not too big or you’ll end up with other problems!)
  • Wear protective footwear when visiting public pools, gyms, yoga studios, and communal showers or change rooms to prevent toenail fungus
  • Wear moisture-wicking socks and change your socks midday to prevent toenail fungus and bacteria buildup
  • Wear shoes made from breathable materials to prevent toenail fungus and bacteria buildup
  • Avoid toenail trauma

Our clinic store is open 7 days a week and offers a variety of nail and foot care products.

A chiropodist at your clinic can also provide nail care and a medical pedicure.  A medical pedicure done by a foot specialist feels just as nice as a cosmetic pedicure, while also giving you the chance to get your toes and feet tended to by a licensed foot specialist.  A licensed foot specialist can recognize and tend to any potential issues that may cause toenail discolouration in the future. 

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Carolina Charles

Patient Relation Coordinator (She/Her)

If you’ve been to the clinic before, chances are you had the pleasure of meeting Carolina! Carolina’s daily goal is going above and beyond to make sure patients are always completely satisfied. Having worked in the podiatry industry for 22 years, Carolina brings a wealth of knowledge pertaining to client service, insurance policies, and procedures.​ She steers the ship to make sure everything runs smoothly on the daily. Carolina is known for spicing up every outfit with her signature costume jewellery.