Changes in Toenail Color- What Does It Mean?

Aug 13

4 min read

Close-up of four toes with toenails showing yellow, brown, black, and pale discoloration against a white background

Providing pedicures throughout the Triangle has opened my eyes to just how diverse and unique the appearance of toenails can be from patient to patient. A mobile foot care nurse completing a nail assessment can be an important part of identifying changes that may point to underlying health conditions. Yes—your toenails can tell you a lot about your health. Changes in toenail color, thickness, texture or shape can sometimes provide clues about what is happening beneath the surface.

Why Are My Toenails Discolored?

Close-up of toes with a discolored big toenail and dark bruise-like staining, suggesting nail injury or fungus on a white background

Have you noticed that one or more of your toenails has changed color? Toenail discoloration can appear brown, gray, green, yellow, black, or as a streak through the nail. While some color changes may be harmless, others can indicate trauma, infection, or another underlying health condition.

Because there are many possible conditions that can cause your toenail discoloration, determining the exact cause can sometimes be challenging without evaluation by a local podiatrist, dermatologist, or foot care specialist.

Why Seeing a Podiatrist Can Be Helpful

Doctor in gloves examines a patient's sole for calluses, with a stethoscope in a bright clinic.

There are a variety of reasons your toenails may become discolored. In some cases, the appearance of the nail may provide clues about what is causing the change. However, a nail culture or laboratory testing may be needed to accurately identify whether bacteria, fungus, or another organism is involved.

A skilled mobile podiatrist or dermatologist can obtain a sample by taking a small piece or scraping of the toenail and/or underlying tissue. The sample can then be sent to a laboratory for testing. This can help determine whether the discoloration is related to a fungal infection, bacterial infection, trauma, or another condition. At that point they can choose the topical ointments or solutions to treat the organism identified on the culture.

What Different Toenail Colors May Mean

Close-up of toes with thick, yellowed toenails, showing a possible fungal infection against a plain light background.

Certain clinical findings can give a medical provider clues about the cause of toenail discoloration.

Green Toenails

A green toenail can sometimes be associated with Pseudomonas, a type of bacteria that can cause a discoloration underneath or within the nail. This is sometimes referred to as " nail syndrome."

Brown or Dark Toenails

A dark toenail can have several possible causes.

Sometimes brown discoloration is the result of blood underneath the nail plate following trauma. You may not remember injuring your toe because the trauma could have occurred weeks, months, or even years earlier.

Brown pigmentation can also be a finding, particularly in individuals with darker skin tones. Some people naturally develop a brown or dark-colored band running through one or more toenails. If the line has been present for years or for most of the person’s life without changing, it may simply represent normal pigmentation.

However, a new or changing dark spot or streak in a toenail should always be evaluated by a medical professional. In some cases, a dark streak can be associated with a type of skin cancer called melanoma.

One finding that may be particularly concerning is when the pigmentation extends from the nail onto the surrounding skin or cuticle. This is sometimes referred to as a Hutchinson sign. If you notice a widening, changing, or irregular dark streak, it is important to have it evaluated by a mobile podiatry service, local foot doctor, or dermatologist.

Gray, Brown or Yellow Toenails

Gray, brown, or yellow toenails can sometimes indicate a nail infection also known as onychomycosis. However, discoloration does not automatically mean that you have toenail fungus. For example, toenails that are yellow but not particularly thick may sometimes be related to repeated nail polish use. This is one reason that simply looking at the nail does not always provide a diagnosis.

Thick, Chalky and Discolored Toenails

When toenails become thick, chalky, brittle, and discolored, a toenail fungus may be one cause. Toenail fungus can sometimes develop after trauma to the nail. Something as simple as repeatedly bumping your toe, dropping something on it, or hitting your toe against furniture can damage the nail plate. Once the nail becomes damaged, it may become more susceptible to developing an infection.

In some cases, toenail fungus can be picked up in places such as gyms, locker rooms, and communal showers, particularly when proper hygiene practices are not followed. Individuals with medical conditions, including diabetes, neuropathy, or peripheral vascular disease, may also be more susceptible to developing fungal toenail infections.

What Should I Do About Color Changes in My Toenails?

If you notice an unusual change in the color, thickness, or appearance of your toenails, consider having your feet and nails evaluated by a qualified professional such as a podiatrist (foot doctor), dermatologist, certified foot care nurse, or your primary care provider.

A mobile medical pedicure in Raleigh NC can be a way to have your feet and toenails assessed in the comfort of your home. During a foot and toenail evaluation, a foot care specialist can identify changes that may warrant further medical evaluation.

A foot care specialist can also help determine whether an over-the-counter product may be appropriate or whether you should see a podiatrist for evaluation and possible prescription-strength treatment.

Can Toenail Fungus Be Treated?

Infographic of fungal nail infections and athlete’s foot, showing feet and hands with discolored nails and labeled infection types.

There are topical and oral treatment options available for toenail fungus. However, toenail fungus can be extremely difficult to eliminate. Treatment may take months to years because the healthy nail needs time to grow out- approximately 1 year- and some infections may require more than one treatment approach.

If you suspect you have toenail fungus, getting the condition properly evaluated by a podiatrist or mobile foot care nurse can help ensure that you are treating the correct problem rather than simply treating the appearance of the nail.

When Should You Have a Toenail Evaluated?

Four close-up panels of fingernails showing dark streaks, yellowing, and discoloration on a teal background, labeled A–D.

Consider seeking evaluation if you notice:

• A new dark or black streak in the toenail

• Discoloration that is spreading or changing

• Pigmentation extending onto the skin surrounding the nail

• Green discoloration

• Thick, brittle or chalky nails

• Persistent yellow, brown or gray discoloration

• Pain, drainage, redness or swelling around the nail

• A toenail that has changed significantly after trauma

Toenail discoloration isn't always a sign of something, but it shouldn't automatically be dismissed as toenail fungus either. A professional evaluation can help determine what may be causing the change and whether additional testing or treatment's appropriate.