To clear up dark green toenails and fingernails, you need to start by diagnosing the reason for the nail condition. Toenail fungus and green nail syndrome are often confused, and it’s easy to understand why, but you can quickly learn how to tell them apart easily.
Do I have dark green toenail fungus or green nail syndrome? Green nail syndrome (GNS) is a bacterial, not a fungal, infection. Toenail fungus (onychomycosis) causes yellow or brown, crumbly nails while green nail syndrome (chloronychia) turns nails green. Fungal infection results in a cheese-like smell, while green nail syndrome smells sweet and fruity.
We’ll look more closely at the differences between dark green toenail fungus and green nail syndrome. We’ll also provide information about the treatment of bacterial and fungal nail infections.
Table of Contents:
Green Toenail Fungus vs. Green Nail Syndrome
There are several species of fungi that cause toenail fungal infections. However, each kind causes similar symptoms. These include:
- Yellow or brown discoloration
- The nail crumbling away and becoming misshapen
- Onycholysis, i.e., where the nail lifts away from the nail bed
- A fungal smell, similar to cheese
Green nail syndrome is caused by a bacterial infection, not fungus. Symptoms include:
- Yellow-green discoloration, ranging to greenish-black if severe
- Onychodystrophy, i.e., the nail becoming misshapen
- The nail lifting away from the nail bed
- A smell similar to sugary fruit, grape juice, or tortillas
The symptoms for green nail syndrome are quite similar to toenail fungus. Let’s take a look at each in depth, to help you figure out which condition you have.
What is Green Nail Syndrome (GNS)?
Green nail syndrome, also known as chloronychia, is caused by Pseudomonas aeruginosa. Pseudomonas aeruginosa is a kind of bacteria found in still soil and stagnant water.
It isn’t common for it to affect people. But it’s known as an ‘opportunistic’ bacterial strain. Green nail syndrome is minor compared to the other conditions it causes. It’s responsible for:
- Your nails turning green
- Pneumonia, if it enters the lungs
- Wound infections, even leading to septic shock and tissue damage
- Necrotizing enterocolitis in the gut, which again damages tissue
According to the journal Clinical Interventions in Aging, it often affects older people. It will attack anybody whose hands or feet are regularly submerged in water. You can also catch it from gardening, even if you wear gloves.
What Does Green Nail Syndrome Look Like?
The most obvious sign of green nail syndrome is that your nail turns green. This green color first appears as a spot. Over time, it comes to affect the whole nail. If you have a green spot on the toe, then this is your issue.
The green color itself is caused by a chemical compound called pyoverdine. This chemical is secreted by the bacteria, and stores iron for later use. The stronger the infection, the more pyoverdine is produced, and the greener your nails become.
The color ranges from a yellow-green, to deep grass green. It isn’t uniform, as the nail is typically deformed too. There will be parts of the nail that appear darker, almost black. There will be other lighter parts.
It appears as stripes running from side to side. This is because of intermittent episodes of infection. The infection gets stronger and weaker in waves as the body tries to fight it off.
Green nail syndrome may also co-occur with other nail issues. These include:
- The nail coming away from the nail bed
- The nail pointing to the side (onychogryphosis)
- The skin around the nail becoming red and swollen (infected)
These nail issues all cause injury to your nails. That’s why it’s common to have a green toenail after injury. Bacterial infection may occur in one nail, or several. It can affect toenails and fingernails.
How Does Green Nail Syndrome Occur?
Pseudomonas aeruginosa lives in stagnant water and soil. Contact with either of these can cause green nail syndrome. That’s especially the case if you don’t wash them off after contact.
The chances increase if there is damage to your nails. This is similar to how other bacterial infections start. Both chronic and acute nail trauma can precipitate infection.
Chronic nail trauma can be caused by something as simple as tight-fitting shoes. Acute trauma occurs when you drop something heavy on your nail, or when the nail rips away.
The typical way that infection occurs is after onycholysis. This is when the nail comes away from the nail matrix. The infection gets underneath the nail, causing a large green spot in the center.
Infections can be caused by other bacteria. Staphylococcus aureus and any of the Klebsiella subspecies may also infect nails. Infections by other bacteria don’t necessarily cause green discoloration.
What Does Toenail Fungus Look Like?
Fungal toenail infection is more common than green nail syndrome. Its most recognizable symptom is that it turns your nails yellow. In severe cases, that yellow will verge on brown. There are four kinds of infection. These are as follows:
- Distal subungual onychomycosis. The infection gets under the nail and attacks the nail plate.
- White superficial onychomycosis. This causes small white spots on the top layer of the nail. The underside of the nail is unaffected.
- Proximal subungual onychomycosis. Highly uncommon, this is where the infection starts at the cuticle. It’s a sign of poor immune health.
- Candidal onychomycosis. This is caused by Candida yeasts, and attacks your toenail(s) if your foot is wet for a long time.
Toenail fungal infection is caused by one of several fungus species. Each species acts in the same way. The fungus attacks the nail’s keratin, which provides structure and strength.
Over time, the nail becomes thicker as the keratin is essentially churned up. Because the structure is destroyed, the nail turns brittle, crumbly and distorted over time. You may also notice a cheesy odor and dark debris under the nail.
What Else Causes Nails to Turn Green?
These two conditions are the most likely culprits if your nails turn green. However, not all causes are necessarily health related. One such cause is the copper in your water.
Copper is known to cause discoloration. For example, it can turn the inside of your toilet tank blue-green. It can also give blond hair a greenish hue.
If you spend a lot of time washing dishes, it can turn your fingernails slightly green. In this context, then perhaps if you frequently use a foot spa, then the same effect could occur.
Aside from that, there are no known medical reasons why your nails should turn green.
Toenail Fungus or Green Nail Syndrome Biopsy
A biopsy is where a doctor takes a small amount of tissue for testing. Doctors perform biopsies to identify precisely what’s wrong with your nail. They may take either part of the nail plate, or part of the nail bed.
They will then take the tissue and put it through a process called PAS staining. Periodic acid-Schiff staining involves placing the tissue in a jar with an acid. The acid then turns purple-magenta if certain things are present, e.g., glycogen. This indicates infection.
Biopsies are simple, effective, and safe. They’re also often necessary as some antifungals and antibiotics only work for certain conditions. Biopsies, therefore, allow them to prescribe the best treatment for toenail fungus available.
Doctors don’t always need to perform a biopsy. They’re often familiar enough with fungal infections to spot one by sight. The same applies to green nail syndrome. Both conditions are recognizable if you spend enough time around them.
However, according to Podiatry Today, doctors can get it wrong. So, considering how simple the process is, you should ask for one.
Can You Have Toenail Fungus and Green Nail Syndrome?
One issue is that toenail fungus and green nail syndrome can occur at the same time. It’s quite likely. Both forms of infection occur because of:
- Nail trauma, either chronic or acute
- Poor foot hygiene, e.g., re-wearing socks or not washing
- Allowing the feet to stay damp or wet
As such, you can catch both at the same time. If this occurs, you’ll have a thick green toenail. It will also become crumbly in places.
The two infections work together, in a way. Fungal infection breaks down the nail, causing damage. You’re then more likely to get a bacterial infection too. Plus, bacterial infection inhibits the ability of antifungal compounds to reach deep-down fugal spores.
If so, you will have to begin a combined treatment, e.g., antibiotics and an antifungal cream. In severe cases, it may be better to have the nail surgically removed. Your doctor will advise you on a course of treatment.
Green Nail Syndrome Treatment
The original treatment for green nail syndrome was avulsion. This is complete removal of the nail. Today, only the nail that’s come away from the bed is cut away. Then, doctors treat green nail syndrome with a mix of topical and oral treatments.
For minor cases, topical application of an antibacterial cream such as gentamicin is sufficient. Normally a routine such as a twice-daily application is prescribed. For severe cases, an oral quinolone (ciprofloxacin) is recommended.
Bacterial infections are easier to treat than fungal infections. Treatment takes from a month to six weeks. After this time, the entire nail plate may be completely cured.
Toenail Fungus Treatment Options
Toenail fungus can be treated topically. However, it can take months or years, depending on the severity of the infection, for it to go away.
A twice-daily application is recommended. However, there are several steps involved aside from rubbing cream into your nail. They include:
- Using a nail softening cream. The softer the nail, the more cream it will absorb. This is necessary as it needs to reach the nail bed
- Bathing before applying antifungal cream. This further softens the nail, making the application more effective
- Allowing the cream to dry in place. Nail takes longer to absorb cream than skin
- Avoiding further nail trauma. Avoid wearing tight socks and shoes
Avulsion, i.e., complete removal, is still the treatment of choice in severe cases. The nail will take between six months and a year to grow back. Throughout this period, you need to practice good foot hygiene to prevent the infection from returning.
Whatever you do, don’t pick a course of treatment without getting a diagnosis. The wrong treatment will be ineffective. In the worst case, it may make the issue more severe. A doctor can definitively tell you whether you have toenail fungus or green nail syndrome.
