Brown Nail Discoloration: What’s Causing Your Nail Change?

Changes in your nails can be alarming, and they’re a common reason for people to seek medical advice. These changes can be indicative of various nail disorders. Nail discoloration can range from subtle changes in color to dramatic changes in the texture or shape of the nail.

When nails turn brown, it’s especially important to get medical advice. Brown nail discoloration can be a sign of something benign, but it can also indicate a more serious underlying condition.

This article will give you a comprehensive overview of nail discoloration brown, including the causes, diagnostic approaches, and management strategies. We’ll explore both melanocytic (pigment-related) and non-melanocytic causes.

Dermoscopy (using a special magnifying device to examine the nail) and a detailed clinical history are critical to diagnosing the cause of nail discoloration. The goal is to give you the information you need to understand the factors that can cause brown nail changes and guide you toward appropriate action.

Understanding Nail Pigmentation

When nails change color, it’s often because of how much pigment is there, and where it came from.

Melanocytic vs. Non-Melanocytic Pigmentation

Melanonychia is the term for when nails darken because of melanin, the pigment that gives skin and hair its color. Melanin in nails can increase for two reasons:

• Melanocytic activation (when the body makes more melanin without adding cells called melanocytes)
• Melanocytic proliferation (when the body increases the number of melanocytes)

Melanonychia can show up as long stripes, a general darkening of the nail, or bands across the nail.

Sometimes, nail discoloration happens for reasons other than melanin. These causes are called non-melanocytic pigmentation.

Examples of non-melanocytic pigmentation include:

• a subungual hematoma (blood trapped under the nail)
• certain medications
• infections

These causes often look different from melanonychia, which can help you figure out what’s going on.

Exogenous vs. Endogenous Pigmentation

Pigmentation can also be described as exogenous or endogenous.

Exogenous pigmentation means the color comes from something outside your body, such as dyes, chemicals, or even dirt stuck under your nail. Usually, as your nail grows, the discoloration will move further out from the cuticle.

Endogenous pigmentation means the color comes from something inside your body. This could be melanin made by melanocytes, or it could be pigment from a disease or medication that affects your whole system.

Non-melanoma causes of brown nail discoloration

Brown nail discoloration can result from a variety of causes that are not related to melanoma. Here are a few:

Subungual hematoma

A subungual hematoma is a common reason nails turn brown or black. It happens when trauma injures the nail, causing blood to pool under the nail plate. Usually, the discoloration is localized, and you’ll notice pain or tenderness.

If you can’t remember what caused the injury, a doctor may want to investigate further to be sure there isn’t something else going on.

The color changes as the blood degrades, going from red/purple to brown/black. If you’ve ever had a bruise, you’ve seen this process in action.

Fungal infections (Fungal Melanonychia)

Certain fungal infections can cause brown or black band-like pigmentation, and can sometimes be confused with keratin debris. These infections often involve the nail plate and may be associated with other signs of fungal infection, such as thickening or crumbling of the nail.

Diagnosing a fungal infection involves microscopic examination and culture of nail clippings. Treatment typically involves topical or oral antifungal medications.

Pseudomonas aeruginosa infection

Although Pseudomonas infections are often associated with green nails, they can sometimes cause brownish discoloration. This is more likely to occur when the nail plate separates from the nail bed (onycholysis).

This infection is often characterized by a foul odor. Treatment usually involves topical antibiotics or antiseptic soaks.

Medications

Many medications, both systemic and topical, can cause nail pigmentation.

Chemotherapy drugs are a well-known cause of nail discoloration, but other medications that can cause brown nail pigmentation include certain antibiotics, antifungals, and antimalarials.

Medication-induced pigmentation is usually diffuse and affects multiple nails. Discontinuing the offending medication, if possible, often resolves the discoloration.

Environmental factors

Exposure to certain chemicals or dyes can cause brown nail staining. This is more common in people who work with these substances regularly.

The discoloration is usually superficial and can be removed with gentle scrubbing.

Melanocytic causes of brown nail discoloration: Melanonychia

Melanonychia is the medical term for brown or black discoloration of the nails. It happens when melanocytes, the cells that make pigment, produce too much melanin in the nail unit. Melanonychia can be caused by melanocytic activation, melanocytic proliferation, or other factors.

Benign Melanocytic Activation

Sometimes, brown nail discoloration is not a sign of cancer, but instead a sign of benign melanocytic activation, which means the melanocytes are more active than usual but not cancerous. Common causes include:

• Racial melanonychia: This is a very common cause of brown stripes or bands on the nails, especially in people with darker skin tones. It’s caused by extra melanin production in the nail matrix. It usually looks like multiple thin brown or black lines that run from the base of the nail to the tip.
• Pregnancy: Pregnancy can also cause melanocytes to become more active, leading to nail pigmentation. This is due to hormonal changes and usually goes away after delivery.
• Benign melanocytic nevi (moles): Moles can sometimes form in the nail matrix, causing a longitudinal brown band on the nail. These moles are usually stable and don’t change quickly. In children, this is often a benign nevus.

Melanocytic Proliferation: Nail Melanoma

Nail melanoma is a rare but serious type of skin cancer that can appear as brown or black discoloration of the nail. It’s important to tell the difference between nail melanoma and harmless causes of melanonychia.

If only one nail is affected and it has dark brown or black pigment, that may be a sign of a cancerous process.

Key features that suggest nail melanoma include:

• The pigmented band grows or changes quickly.
• The borders or pigmentation are irregular.
• The pigment involves the proximal nail fold (Hutchinson’s sign), which is when the pigment extends onto the skin around the nail.
• The nail is deformed.

The ABCDEF criteria can help you assess for nail melanoma:

• Age (50-70s is most common)
• Band (brown or black band)
• Change (rapid change in size, shape, or color)
• Digits (most commonly affects the thumb, great toe, or index finger)
• Extension (pigment extending onto the skin around the nail – Hutchinson’s sign)
• Family history (personal or family history of melanoma)

Researchers are actively working on algorithms to help health professionals identify nail melanoma as early as possible.

Diagnosing brown nail discoloration

It can be hard to know what’s causing a change in your nail color, so your doctor will probably start by asking you some questions and doing a physical exam.

History and physical exam

Your doctor will want to know:

• How long you’ve had the discoloration
• If you remember injuring the nail
• What medications you take
• If you’ve been exposed to dyes or chemicals
• If anyone in your family has a history of nail problems or melanoma

During the physical exam, your doctor will look at:

• How many nails are affected
• What pattern the discoloration makes (a line, a spot, or all over the nail)
• If there are other changes to the nail, like being misshapen or separating from the nail bed
• The skin around the nail, checking for Hutchinson’s sign

Dermoscopy and onychoscopy

Dermoscopy is like using a magnifying glass to look at your nail and the skin underneath. This can help your doctor see whether the pigment is from melanoma or something else.

Onychoscopy can help determine if the discoloration is from something on the outside of the nail or from pigment inside the nail. It can also help spot signs of nail melanoma, like uneven coloring or a micro-Hutchinson’s sign (pigment in the skin around the nail).

Some things dermoscopy can show include the width of the discolored band, if there are gray or black colors, and if the nail is misshapen. All of these things can help your doctor figure out the cause of the problem.

Biopsy

If your doctor thinks you might have nail melanoma, you’ll need a biopsy. A doctor who’s experienced with nail problems should do the biopsy, and the type of biopsy will depend on where the discoloration is and how big it is.

What can you do about brown nail discoloration?

The first step is to find out what’s causing the discoloration.

Sometimes, that means that you and your doctor will try taking you off a medication. Or it might mean treating an infection or avoiding whatever is irritating your nails.

Treatment options

Once you know what’s causing your nails to turn brown, treatment depends on what the problem is and how you feel about it.

For example, if you have a fungal infection, you’ll need to use antifungal medicine. If you have a bacterial infection, you’ll need antibiotics.

Nail melanoma is a serious condition that requires immediate and aggressive treatment. That might mean surgery, chemotherapy, or both.

Supportive care

Sometimes, you don’t need any specific treatment. For example, if you have racial melanonychia, a harmless condition that causes dark lines in your nails, you won’t need treatment.

However, no matter the reason your nails are discolored, you can take steps to keep your nails clean and trimmed. Doing so can improve how they look and prevent other infections from taking hold.

If you’re concerned about nail discoloration, schedule an appointment with your healthcare provider. They can help you determine what’s causing the problem and recommend the best course of treatment.

Frequently Asked Questions

In Closing

Brown discoloration of your nails can be caused by many different things, from something harmless to a serious disease. If you notice a brown streak or discoloration on your nail, it’s important to see a doctor to find out what’s causing it.

Your doctor will ask you questions and examine your nails. They might also use special tools like a dermatoscope or onychoscope to get a better look. These tools can help them tell the difference between a harmless spot and something more serious, like melanoma.

Finding the cause of nail discoloration early and treating it properly can help prevent problems and improve your health. This is especially important if you have nail melanoma.