Nail fungus, also known as onychomycosis, is a common infection that can affect your fingernails and toenails. Most of the time, you’ll notice it because your nail changes color, gets thicker, and maybe even starts to crumble a little. But sometimes, nail fungus shows up as stripes or lines on your nail.
If you’re seeing lines on your nails, it’s important to know that nail fungus isn’t the only possible cause. You might be seeing lines because of an injury, a vitamin deficiency, or some other condition. This article will help you understand the different kinds of nail lines and streaks you might see, and how to tell if the lines are caused by nail fungus or something else.
Getting the right diagnosis is key, because different nail problems need different treatments. Plus, sometimes nail changes can be a sign of a more serious health problem, so it’s always best to get it checked out by a doctor.
Basic Nail Anatomy and Examination
To understand what those stripes on your nails might mean, it helps to know a little bit about nail anatomy. Your nail unit consists of the nail plate (the hard part you see), the nail bed (the skin underneath), the nail matrix (where the nail grows from), and the tissues around the nail.
Looking at your nails can provide valuable clues about your health. A good nail examination can help diagnose all sorts of conditions, from skin problems to diseases affecting your whole body.
When checking your nails, it’s important to remove any nail polish first. Note the color, shape, and thickness of the nail, and look for any lines, lesions, or other abnormalities. It’s also a good idea to take pictures and measurements to track any changes over time.
What is a fungal nail infection?
The medical term for nail fungus is onychomycosis. It’s a pretty common infection, and as discussed in our guide on toenail fungus versus injury, it’s more likely to occur in your toenails than your fingernails.
Several types of fungi can cause onychomycosis, including dermatophytes, yeasts, and molds. These infections can cause discoloration and changes to the texture of your nails, and sometimes lead to conditions such as green fingernail fungus. Sometimes, these changes appear as lines or streaks on the nail.
What are the different kinds of fungal nail infections?
Nail fungus shows up in a number of ways. Here are some of the most common:
Distal Subungual Onychomycosis (DSO)
This is the most common type of fungal nail infection. It happens when fungi get into the nail bed and cause discoloration, thickening, and separation of the nail from the nail bed. You might see yellowish or brownish streaks.
White Superficial Onychomycosis (WSO)
With this type of infection, fungi infect the surface of the nail plate. This causes white, chalky patches that can turn into larger areas. You might see white streaks or lines on the nail surface.
Proximal Subungual Onychomycosis (PSO)
This less-common infection often affects people with compromised immune systems. The fungi get into the nail fold and infect the nail matrix. This can cause discoloration and distortion of the nail plate from the base, and you might see streaks running across or up and down the nail.
Fungal nail infection: Symptoms and diagnosis
How do you know if those lines on your nails are nail fungus stripes, or something else? Look for other symptoms of a fungal nail infection, like:
- Thickening of the nail
- Discoloration
- Brittleness
- Separation of the nail from the nail bed
Fungal nail lines are usually accompanied by these other telltale signs of infection. If you’re still not sure, it’s important to get a diagnosis from your doctor. They can perform a potassium hydroxide (KOH) stain or test nail clippings for fungal staining to confirm whether you have a fungal nail infection.
White nail lines: Leukonychia striata
Sometimes, a stripe on your nail isn’t about fungus. Leukonychia striata is a condition that causes white lines or stripes to appear on the nails. These lines can be a sign of different things, from minor injuries to more serious health issues.
There are actually two types of leukonychia: true and apparent. The difference lies in where the color change originates.
True leukonychia
True leukonychia is a change in the nail itself. The white discoloration starts within the nail plate.
What causes it?
- Trauma to the nail matrix: This is the most common cause. Even a small bump or injury can disrupt nail growth.
- Onychomycosis: Yes, nail fungus can sometimes cause white lines as well.
- Inherited conditions: Some genetic disorders, like Hailey-Hailey disease and Darier disease, can affect the nails.
Apparent leukonychia
Apparent leukonychia is when the white color comes from the nail bed underneath the nail plate. The nail itself is fine; it’s the tissue underneath that’s causing the color change.
These lines can be a sign of:
- Muehrcke lines: These are associated with low levels of albumin in the blood (hypoalbuminemia).
- Mees lines: These transverse (across the nail) white lines can be a sign of acute stress on your system or exposure to toxic metals.
- Half-and-half nails: As the name suggests, these nails are white on the bottom half and pink or brown on the top. They’re often linked to kidney disease.
- Terry nails: These nails are mostly white, with a narrow pink or red band at the tip. They can be associated with liver disease, heart failure, and diabetes.
Longitudinal Melanonychia: Vertical Brown-Black Nail Lines
Longitudinal melanonychia is a fancy term for brown or black vertical stripes running the length of your nail, from the base to the tip. Don’t panic if you see them, but don’t ignore them, either.
These stripes can be caused by a bunch of things, including:
- Trauma
- Infection
- Medications
- Endocrine disorders
- Benign melanocytic activation (basically, your pigment cells are just a little overactive)
- Nail matrix nevus (a type of mole)
So, when should you worry? Here’s when you need to see a doctor immediately:
- The stripe is wider than 6 mm
- The stripe has irregular pigmentation or blurred edges
- The stripe is growing quickly or changing its appearance
- You see a Hutchinson sign (pigment extending onto the skin around your nail)
- You have a family history of melanoma
In these cases, it’s essential to rule out melanoma, a dangerous form of skin cancer.
Longitudinal erythronychia: Vertical red nail lines
Longitudinal erythronychia is the medical term for red lines that run vertically down your nail, from the base all the way to the tip.
These red streaks can appear on just one nail, or on multiple nails. The lines are generally around 3 mm wide.
A benign tumor called a glomus tumor can cause a red line to appear on one nail. Other causes of a single red nail streak include trauma, warts, and psoriasis.
If you have red streaks on more than one nail, it could be a sign of:
- Lichen planus
- Darier disease
Beau Lines
Beau lines are horizontal grooves that run across your fingernails or toenails. These stripes are a sign that your nail growth was temporarily put on pause.
What causes these lines? They can be due to stress, a systemic illness, or even certain medications. The location of the Beau line can actually tell you when you experienced the stressor, since fingernails grow about 3 mm per month, and toenails grow at a rate of about 1 mm per month.
Fungal nail infection treatment
If you’ve got nail fungus stripes, don’t worry! Several effective treatments can help you get rid of the infection. Here are some common approaches:
- Topical antifungal medications: These are creams, gels, or lacquers that you apply directly to the affected nail. They’re often used for mild to moderate infections.
- Oral antifungal medications: For more severe infections, your doctor may prescribe oral antifungal pills. These medications work from the inside out to kill the fungus.
- Laser therapy: This is a newer treatment option that uses laser light to target and destroy the fungus. It’s still emerging, so talk to your doctor about whether it’s right for you.
- Surgical removal of the nail: In the most severe cases, where other treatments haven’t worked, your doctor may recommend surgically removing the infected nail.
Fungal nail infection prevention
The best way to deal with nail fungus is to not get it in the first place. Review our press on nail guide and prevention tips to help prevent a fungal nail infection:
- Practice good hygiene. Wash your hands and feet regularly, and keep your nails trimmed short.
- Wear appropriate footwear. Choose socks that wick away moisture, and make sure your shoes aren’t too tight.
- Avoid sharing personal items. Don’t share things like towels or nail clippers with other people.
- Use antifungal products. You can use an antifungal powder or spray on your feet and in your shoes.
If you suspect that you may have a fungal nail infection, see your doctor to get a diagnosis and discuss treatment options.
Complications from nail fungus
Nail fungus isn’t just a cosmetic issue; it can lead to more serious problems if left untreated. Some of the complications that can arise from a fungal nail infection include:
- Pain and discomfort in the affected nail, which can make it difficult to walk or wear shoes.
- Secondary bacterial infections, which can occur when the damaged nail allows bacteria to enter the skin.
- Spread of the infection to other nails or skin, potentially affecting other parts of your body.
- Increased risk of complications in individuals with diabetes, as they may have a harder time fighting off the infection.
Summary
Nail lines and streaks can be caused by a variety of things, and it’s important to tell the difference between a fungal infection and something else. Some nail issues are harmless, but others can be signs of a more serious condition.
If you notice stripes or other unusual changes in your nails, don’t try to diagnose yourself. Get professional medical advice for a proper diagnosis and treatment plan. If it is a fungal infection, starting treatment early can make a big difference.
You can help prevent fungal nail infections by keeping your feet clean and dry and wearing breathable shoes.