Is Diabetes Causing Your Yellow Toenails and Foot Fungus?

If you want to know why your toenails are yellow, we discuss possible causes in this article.

Yellow toenails can be associated with diabetes in some cases, which is why it’s important to stay on top of foot care and diabetes management.

We’ll explain some of the reasons diabetes can cause yellow toenails, explore other possible causes of yellow nails, and how to treat yellow toenails and get rid of foot fungus.

Why can diabetes turn your toenails yellow?

High blood sugar

Having diabetes puts you at greater risk of infections because of higher blood sugar levels. 

When your blood sugar levels are higher than they should be, it can impact your immune system and increase your susceptibility to illness and infection.

Chronic high blood sugar can also negatively impact healing by reducing circulation and can cause infections to last much longer compared to people without diabetes.

Toenail fungus (onychomycosis)

One of the main reasons for yellow toenails is a fungal infection. The medical term for nail fungus is onychomycosis.

Diabetes is considered one of the main predisposing factors for developing onychomycosis, impacting around 30% of people with diabetes.

Other signs of a fungal infection besides yellowing of your nails include:

  • Thickened nails
  • Discolored nails (including yellowing)
  • Brittle, crumbly, or ragged nails
  • Misshapen nails
  • Toenails that have separated from the nail bed
  • A foul smell coming from your toenails

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Other causes of yellow nails

There are other potential causes of yellow nails besides having diabetes, such as:

Yellow Nail Syndrome

This condition is much rarer than yellow nails from diabetes, with fewer than 400 cases documented. 

Yellow Nail Syndrome not only impacts your nails but your lungs and limbs as well.

As well as causing yellowing of your nails, Yellow Nail Syndrome can cause your nails to fall off completely. 

It’s unclear what causes this condition, but it’s thought to be linked to poor circulation, lymphatic drainage issues, and fluid buildup around your lungs.

People at higher risk of developing Yellow Nail Syndrome include those with autoimmune disorders, cancer, and thyroid disease.

Kidney disease

Another possible cause of yellow nails is kidney disease. If your kidneys aren’t filtering your blood well enough, a buildup of nitrogen waste can cause your nails to turn yellow.

Having diabetes increases your risk of kidney disease. 

Your healthcare provider will routinely check your kidney function if you have diabetes to ensure your kidney health hasn’t been negatively impacted. 

If your kidney function is healthy, you can likely rule out kidney problems as the cause of your yellow nails.

Use of certain medications

Some medications have been associated with yellow nails. If you’re taking a prescription medication, ask your healthcare provider or pharmacist if yellowing nails is a common side effect.

Thyroid problems

Having an overactive thyroid (hyperthyroidism) can cause yellowing of your nails due to onychomycosis, the same condition that impacts many people with diabetes.

Vitamin deficiencies

Deficiencies in vitamins like vitamin E might cause yellow nails. 

If you suspect you have a nutrient deficiency, ask your healthcare provider about blood tests for an accurate diagnosis.

Possible complications from yellow nails

Having your toenails turning yellow isn’t only a cosmetic issue that might cause embarrassment. 

Permanent nail scars and damaage

If you have onychomycosis, it can be an indicator of poorly controlled diabetes (high blood sugar levels). Untreated onychomycosis can cause permanent scarring and damage to your nail beds.

Risk of diabetic foot ulcers

If you have a fungal infection in your nails from high blood sugar levels, you might also be at greater risk of diabetic foot ulcers. 


Chronic high blood sugar levels can cause nerve damage (diabetic neuropathy) and poor circulation, which leads to reduced sensation and feeling in your feet. 

That means that you can develop a wound that you don’t feel (due to nerve damage), leading to more severe wounds and even amputations from poorly healing wounds.

If you have yellow nails, be sure you’re practicing proper diabetes foot care (more on that later) to make sure you’re not missing any wounds or foot abnormalities that can become more serious if left untreated.

Risk of spreading to your skin

Finally, a fungal nail infection can spread to your skin, causing more issues, which is another risk of having yellow nails.

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How to fix yellow toenails and foot fungus


If yellow nails are from onychomycosis, the yellow nail treatment is an oral medication called terbinafine. 

This medication should be used for 12 weeks for infected toenails.

Topical antifungals don’t tend to work well for onychomycosis, which is why it’s important to get an accurate diagnosis so you can be sure you’re getting the right treatment.

Removing damaged areas of yellow nails

If your toenails don’t improve after a course of terbinafine, your healthcare provider might suggest surgical debridement (removal of damaged areas of the nail) or complete removal of the infected nail.

Once you get onychomycosis, you’re at greater risk of recurrence, which is why prevention is so important.

Preventing yellow nails from diabetes

Prevention is the best medicine, and that’s certainly the case with diabetic fungal infections causing yellow nails.

Proper foot care and management of blood sugars (to minimize the prevalence of infection) are the most effective ways to prevent yellow nails.

Foot care

Diabetes increases your risk of foot infections and wounds, so proper foot care is essential to catch these infections and wounds in the early stages.

Some aspects of diabetes foot care include:

Inspect your feet after you take your shoes and socks off

Check for sores, scratches, or signs of infection, and notify your healthcare provider or podiatrist (foot doctor) if you suspect a problem.

Keep your feet clean and dry

Moist feet can increase the risk of fungal infections and yellow toenails.

Keep your toenails short and clean

Long nails can capture dirt, bacteria, and fungus better than short nails. Be sure to clean underneath your nails if they’re dirty, too.

Don’t share nail clippers with others

Don’t walk barefoot in public

If you’re in a public area like a locker room or shared shower, wear flip-flops and avoid walking barefoot, which spreads fungal infections that can cause yellow toenails.

Don’t use creams between your toes

Avoid the use of creams and lotions between your toes, which can increase the risk of infection.

Avoid certain OTC products

Don’t use over-the-counter products to remove corns or calluses, and don’t remove them on your own, which can lead to wounds and foot infections.

Make sure your shoes fit

Make sure your shoes fit well, which can reduce friction and wounds that can lead to more serious foot infections.

Blood sugar management

The best way to avoid fungal infections that cause yellow nails is to achieve good blood sugar management. 

When your blood sugar levels are controlled, your immune system can do a better job at fighting infections. 

If you do get an infection, good blood sugar levels can promote healing.

Managing your blood sugars involves several aspects, including lifestyle and medications. 

Here is a summary of some ways to promote healthy blood sugar levels to reduce your risk of infections that cause yellow toenails.


Eating a healthy diet is one of the most effective ways to manage your blood sugar levels. 

A diet rich in healthy carbohydrates (carbs) like whole grains, fruits, vegetables, and legumes instead of refined carbohydrates (such as white bread, white rice, and other processed foods) and added sugars is a great place to start.

Getting plenty of lean protein (such as chicken, lean cuts of red meat, and fish) and avoiding sugary beverages are also important aspects of a healthy diet. 

If you have questions about how to eat to manage your diabetes, reach out to a registered dietitian for some help!


If your healthcare provider has prescribed medications for your diabetes, be sure to take them as prescribed. 

Skipping doses can lead to high blood sugar levels, which can put you at greater risk of toenail fungus that causes yellowing of your nails.

Physical activity

Being physically active for 30 minutes most days of the week helps lower your blood sugar levels. 

It can also help your body become more sensitive to insulin, the hormone that lowers your blood sugar levels.


  • The most common cause of yellow toenails in diabetes is a fungal infection called onychomycosis, but there are other potential causes as well.
  • Onychomycosis is usually treated with an oral medication since topical treatments aren’t effective.
  • You can prevent yellow toenails from diabetes by practicing good diabetes foot care and managing your blood sugar levels, which can reduce the likelihood of developing toenail infections that cause yellowing of the nail.

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  1. Trovato L, Calvo M, De Pasquale R, Scalia G, Oliveri S. Prevalence of Onychomycosis in Diabetic Patients: A Case-Control Study Performed at University Hospital Policlinico in Catania. J Fungi (Basel). 2022 Aug 30;8(9):922. doi: 10.3390/jof8090922. PMID: 36135647; PMCID: PMC9500927.
  2. Al Houri H, Al-Tarcheh H, Zghaier O, Salloum S, Haj Ibrahim A, Kouli M. Amlodipine as a Suggested Cause of Yellow Nail Syndrome: A Case Report. Cureus. 2022 Sep 21;14(9):e29396. doi: 10.7759/cureus.29396. PMID: 36304383; PMCID: PMC9585798.
  3. CDC. Fungal Nail Infections.

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