Why Are My Toenails Black? Understanding Causes and Treatments

Have you noticed a dark discoloration under your toenail and found yourself wondering, “Why Are My Toenails Black?” It’s a common concern, and while often not serious, understanding the cause is crucial for proper care and peace of mind.

At Haro Podiatry Center, we specialize in diagnosing and treating various foot and nail conditions. We understand your concern about black toenails and are here to provide comprehensive information on the common causes, effective treatments, and when it’s essential to seek professional medical advice.

Let’s delve into the reasons behind black toenails and what you can do about them.

Common Causes of Black Toenails

Several factors can lead to black toenails, ranging from minor injuries to more serious underlying conditions. Identifying the cause is the first step towards effective management.

Trauma and Injury: The Most Frequent Culprit

The most prevalent reason for a black toenail is trauma or injury. This can occur due to various everyday incidents:

Stubbing your toe: Accidentally hitting your toe against a hard object can cause blood vessels under the nail to rupture.
Dropping heavy objects: An object falling onto your foot can lead to significant trauma and bleeding beneath the toenail.
Ill-fitting footwear: Shoes that are too tight, especially in the toe box, can cause repetitive pressure and friction, resulting in injury. This is particularly common in athletes, hikers, and individuals who wear dress shoes for extended periods.
Repetitive stress: Activities like running or hiking long distances can cause micro-trauma to the toenails, leading to subungual hematomas.

When trauma occurs, blood accumulates under the nail, forming what is known as a subungual hematoma. This trapped blood appears dark red, brown, or black, causing the nail to look discolored. Initially, you might experience throbbing pain and pressure. In most minor cases, a trauma-induced black toenail will resolve naturally as the nail grows out, although this process can take several weeks to months depending on the nail growth rate.

Fungal Nail Infections: A Common Cause of Discoloration

Fungal infections of the toenails, also known as onychomycosis, are another frequent cause of toenail discoloration. Fungi thrive in warm, damp environments, such as inside shoes, socks, and public showers. These infections can penetrate the nail and nail bed, leading to a range of changes in nail appearance.

While fungal infections often cause yellow or white discoloration, they can also lead to a darkening of the nail, sometimes resulting in a blackish hue. Other signs of a fungal nail infection may include:

Thickening of the toenail
Brittleness or crumbling of the nail
Distortion in nail shape
Buildup of debris under the nail
Unpleasant odor

Treating fungal nail infections is important not only to restore the nail’s appearance but also to prevent the infection from worsening or spreading to other nails or skin.

Subungual Melanoma: A Rare but Serious Consideration

Although less common, a black toenail can, in rare cases, be a sign of subungual melanoma, a type of skin cancer that occurs under the nail. Melanoma under the toenail can present as a dark streak or band within the nail that often starts at the base of the nail (cuticle) and extends towards the tip.

Key characteristics of subungual melanoma to watch out for include:

A dark streak or band that is new and doesn’t have a clear history of trauma.
The band is widening or darkening over time.
The discoloration affects the nail fold (skin around the nail). This is known as Hutchinson’s sign.
Bleeding, nail distortion, or pain may occur, but sometimes melanoma is painless in its early stages.
It typically affects only one toenail.

It’s crucial to remember that subungual melanoma is rare, and most black toenails are not cancerous. However, because melanoma is serious and requires prompt treatment, any unexplained dark streak or change in your toenail should be evaluated by a medical professional, such as a podiatrist or dermatologist, as soon as possible to rule out this condition.

Underlying Medical Conditions: Systemic Health and Nail Changes

In some instances, underlying systemic medical conditions can manifest as changes in nail appearance, including discoloration. Certain diseases can affect blood circulation, nutrient supply, and overall nail health, potentially contributing to black toenails. These conditions include:

Diabetes: Diabetes can impair circulation, particularly to the extremities, which can affect nail health and healing.
Peripheral artery disease (PAD): Similar to diabetes, PAD reduces blood flow to the limbs, which can lead to nail discoloration and other nail problems.
Kidney disease: Kidney disorders can cause waste products to build up in the body, which can affect nail health.
Anemia: Iron deficiency anemia can sometimes cause changes in nail shape and color.

If you have any of these underlying health conditions and notice changes in your toenails, it’s important to discuss these changes with your doctor. A black toenail in the context of an underlying medical condition may warrant further investigation and management of the systemic disease.

When Should You See a Doctor for a Black Toenail?

While many black toenails are benign and heal on their own, it’s important to know when to seek professional medical advice. Consult a podiatrist or your primary care physician if you experience any of the following:

Severe pain or pressure: If your black toenail is intensely painful, throbbing, or feels tight, it may require drainage to relieve pressure and pain.
Signs of infection: Increased pain, swelling, redness, warmth around the nail, or pus discharge are signs of a possible infection that needs prompt medical attention.
Discoloration worsening or not improving: If the black discoloration doesn’t improve over time, continues to spread, or changes in appearance without a known injury, it should be evaluated.
Nail thickening or distortion: Thickening, crumbling, or changes in the shape of the nail can indicate a fungal infection or other underlying issues.
Dark streak with no history of trauma: A dark streak appearing on your nail without any preceding injury needs to be assessed to rule out subungual melanoma.
Hutchinson’s sign: Pigmentation of the skin around the nail (nail fold) in association with a dark nail streak is a concerning sign.
Underlying health conditions: If you have diabetes, peripheral artery disease, or any condition affecting circulation or immunity, any changes in your toenails should be checked promptly.

Don’t hesitate to seek professional advice if you are unsure about the cause of your black toenail or if you are concerned about any associated symptoms. Early diagnosis and treatment can prevent complications and ensure optimal nail and foot health.

How to Treat Black Toenails

The appropriate treatment for a black toenail depends entirely on the underlying cause.

Treatment for Trauma-Induced Black Toenails

For most minor trauma-related black toenails, the best approach is often conservative management:

Rest and protection: Avoid further injury to the toe. Wear comfortable, roomy shoes.
Pain relief: Over-the-counter pain relievers like acetaminophen or ibuprofen can help manage pain.
Wait for natural healing: In many cases, the black toenail will resolve as the nail grows out. This can take 6-9 months for a big toenail to fully replace itself.

If there is significant pain and pressure from a large subungual hematoma, a podiatrist can perform a procedure called nail trephination. This involves creating a small hole in the nail to drain the trapped blood, providing immediate pain relief. This procedure should always be performed by a medical professional in a sterile environment.

Treatment for Fungal Nail Infections

Fungal nail infections require antifungal treatment to eradicate the infection. Treatment options vary depending on the severity of the infection:

Topical antifungal medications: For mild to moderate infections, topical antifungal creams, ointments, or nail lacquers can be prescribed. These are applied directly to the nail and surrounding skin.
Oral antifungal medications: More severe or persistent fungal infections often require oral antifungal medications. These medications are taken by mouth and work systemically to kill the fungus. Oral antifungals are generally more effective than topical treatments but may have potential side effects and require monitoring by a physician.
Laser therapy: Laser treatment is a newer option for fungal nail infections. It uses laser energy to target and destroy the fungus in the nail bed. Laser therapy can be effective and often has fewer side effects than oral medications. At Haro Podiatry Center, we utilize advanced laser technology for effective fungal nail treatment.

The choice of treatment will depend on the type and severity of the fungal infection, as well as individual patient factors. A podiatrist can diagnose the infection and recommend the most appropriate treatment plan.

Management of Subungual Melanoma

If a black toenail is diagnosed as subungual melanoma, prompt and aggressive treatment is necessary. Treatment typically involves surgical removal of the melanoma. The extent of surgery depends on the stage and depth of the melanoma and may involve removing the nail unit, the affected toe, or even more extensive surgery in advanced cases. Early diagnosis and treatment are critical for improving outcomes in subungual melanoma.

How to Prevent Black Toenails and Maintain Healthy Toenails

Preventive measures can significantly reduce the risk of developing black toenails and promote overall toenail health.

Wear Properly Fitting Shoes

Wearing shoes that fit well is paramount in preventing trauma-induced black toenails. Ensure that your shoes:

Have adequate toe box space: Your toes should be able to wiggle freely and not be cramped or pressed against the front of the shoe.
Are the right length and width: Shoes should be appropriately sized to avoid excessive friction or pressure points.
Are appropriate for the activity: Wear supportive athletic shoes for sports and exercise and avoid wearing tight or ill-fitting shoes for prolonged periods.

If you need guidance on proper shoe fitting, the experts at Haro Podiatry Center can provide personalized recommendations to help you find comfortable and supportive footwear.

Practice Proper Toenail Trimming

Correct toenail trimming techniques are essential for preventing ingrown toenails and other nail problems that can indirectly contribute to discoloration or infection.

Trim toenails straight across: Avoid rounding the corners, as this can encourage ingrown toenails.
Don’t cut nails too short: Cutting too close to the nail bed can increase the risk of injury and infection.
Use clean, sharp nail clippers: This helps ensure a clean cut and reduces the risk of nail damage or infection.

Maintain Good Foot Hygiene

Good foot hygiene practices are crucial for preventing fungal nail infections and maintaining overall foot health.

Wash your feet daily: Wash your feet thoroughly with soap and water, especially between the toes.
Dry your feet completely: Ensure your feet are completely dry after washing, particularly between the toes, as moisture promotes fungal growth.
Wear breathable socks: Choose socks made of moisture-wicking materials like cotton or wool to keep your feet dry. Change socks daily, and more often if your feet sweat excessively.
Use antifungal powder or spray: If you are prone to sweaty feet or fungal infections, consider using antifungal powder or spray inside your shoes and on your feet.
Avoid walking barefoot in public places: Wear shoes or sandals in public showers, locker rooms, and swimming pool areas to minimize exposure to fungi.

Protect Your Feet from Sun Exposure

While often overlooked, protecting your feet and toenails from excessive sun exposure is important for preventing skin damage, including reducing the risk of melanoma. Apply sunscreen to your feet, including your toenails, when exposed to the sun, especially during prolonged outdoor activities or when wearing sandals.

Concerned About Your Black Toenail? We Can Help

If you are concerned about a black toenail or are unsure of the cause, seeking professional evaluation is always the best course of action. At Haro Podiatry Center in Clifton, NJ, our experienced podiatrists are experts in diagnosing and treating a wide range of foot and nail conditions, including black toenails. Schedule an appointment today and let us help you determine the cause of your black toenail and provide you with the appropriate treatment and guidance to ensure healthy, happy feet. We are dedicated to helping you understand “why are my toenails black” and providing effective solutions for your foot care needs.