What Causes Darkening of Toenails

A person wearing blue gloves during a toenail inspection at Parkwood Skin Clinic.

Are you noticing a dark discoloration on your toenail? A black toenail can be both an unsightly and concerning development. Often associated with various causes like trauma, fungal infections, or more serious conditions such as melanoma, understanding the root cause of a black toenail is crucial.

This blog post will explore the common reasons behind black toenails, the symptoms to watch for, and the effective treatments that can help you address this issue. We’ll also provide preventative tips to keep your toenails healthy and free from discoloration. Whether you’re a runner experiencing the frequent pressure of footfalls or someone concerned about an unexpected change in nail color, this guide is tailored to shed light on all your queries and concerns about black toenails. Join us as we delve into the details of what causes black toenails and how you can treat and prevent them.

Understanding toenail darkening: causes and symptoms

Black toenails can be caused by various factors, including fungal infections, trauma, and medication side effects. Fungal infections can cause discoloration, thickening, and even crumbling of toenails, while trauma can cause blood pooling from blood vessels underneath the nail, resulting in subungual hematoma. Trauma to the toenail may cause the color of black toenail to change from black or purple to brown or greenish-yellow over time.

Chemotherapy drugs can also cause darkening or discoloration of both fingernails and toenails, but this is a temporary side effect that should resolve once the medication is discontinued. Consult a doctor if you suspect your medication is causing the darkening of your toenails, as they may have additional recommendations or alternative treatments.

The Origin of Nail Discoloration: Nail Bed and Nail Matrix

The appearance of pigment in the nail, whether starting from the nail bed or the nail matrix, can indicate various conditions ranging from benign to serious. Understanding where and how this pigment forms is crucial for early diagnosis, and treatment. Here’s an exploration into how pigmentation can originate from both the nail bed and the nail matrix, and what it could potentially signify.

Toenail Discoloration Originating from the Nail Matrix

What is the Nail Matrix?

The nail matrix is the tissue (germinative layer) underneath the base of the nail, hidden under the cuticle. This area is responsible for producing cells that become the nail plate. Because the nail matrix generates the nail’s keratin, changes in this area directly affect the nail’s color, shape, and texture.

Causes of Pigmentation in the Nail Matrix

1. Melanonychia: This condition refers to a dark pigmentation or streaking of the nail, often due to increased melanin production in the nail matrix. Causes of melanonychia include:

Ethnic pigmentation (common and benign, especially in individuals with darker skin)

Nevus (a mole within the nail matrix)

Melanoma (a potentially deadly form of skin cancer that can begin as a pigmented streak in the nail matrix)

2. Injury: Trauma to the nail matrix can cause bleeding or hematoma that appears as a dark coloration under the nail.

3. Infections: Bacterial or toenail fungal infections can affect the nail matrix, leading to changes in nail color and texture.

4. Systemic Diseases: Certain systemic conditions, such as Addison’s, heart or kidney disease,, or vitamin deficiencies, can manifest as pigmentation changes originating from the nail matrix.

Pigmentation Originating from the Nail Bed

What is the Nail Bed?

The nail bed is the skin beneath the toe of the nail plate that extends from the edge of the nail matrix to the hyponychium. It supports the nail above it and contributes to its color and health.

Causes of Pigmentation in the Nail Bed

1. Subungual Hematoma: Trauma to the toe nail can cause blood to collect under the toe nail, presenting as a dark red, dark brown, or black discoloration. This usually starts in the nail bed since it is directly below the nail plate.

2. Fungal Infections: Onychomycosis, or fungal infection of the nail, can cause darkening of the nail bed that appears through the nail plate.

3. Bacterial Infections: Certain bacteria, like Pseudomonas, can infect the nail bed and produce green-black pigmentation.

4. Psoriasis: This chronic skin condition can affect the nails and nail beds, causing abnormal nail growth and discoloration.

When should I be concerned about black toenail?

Discolored toenails can be caused by a variety of factors, ranging from benign to more serious conditions. It’s important to observe other symptoms you may have and consider the specific characteristics of the discoloration. Here are some guidelines on when to be concerned:

1. Persistent Changes: If the discoloration doesn’t improve or worsens over time, it’s worth seeking medical advice.

2. Pain or Discomfort: If the discoloration is accompanied by pain, discomfort, or sensitivity, especially if it affects your walking or wearing shoes.

3. Spread of Color: If the discoloration is spreading to other nails or to the skin around the nails, it could indicate an infection or an underlying health condition or issue.

4. Change in Nail Texture: Changes toe nails such as thickening, brittleness, or changes in shape can accompany discoloration and signal a fungal infection or other conditions.

5. Systemic Symptoms: If you experience systemic symptoms like fever, swelling in the area, or lymph node enlargement in addition to toenail discoloration, it could be a sign of a more serious infection or systemic condition.

6. Black or Dark Discoloration: Though sometimes caused by trauma (subungual hematoma), black or dark discoloration can also be a sign of early stages of melanoma, a serious form of skin cancer, and requires immediate medical attention.

7. Unusual Colors: Yellow nails can be indicative of fungal infection, while green-black nails might suggest a bacterial infection. White nails could be related to nail fungus or other conditions, and blue or purple nails might suggest circulation issues.

8. No Obvious Cause: If you haven’t experienced any trauma to the nail or have not been exposed to substances that could stain the nail, but you notice discoloration, it’s wise to consult a healthcare provider.

9. Underlying Health Conditions: Individuals with diabetes, peripheral vascular disease, or weakened immune systems should be particularly vigilant about any changes in their nails, as they are more susceptible to infections.

In general, changes in nail appearance that are sudden, only affect one nail, or are associated with other symptoms might warrant a closer look by a healthcare professional. While many common causes of toenail discoloration are benign, such as nail polish staining or minor trauma, it’s always better to err on the side of caution when it comes to changes in your body. If in doubt, seeking advice from a healthcare provider can provide peace of mind and ensure any potential issues are addressed promptly.

What deficiency causes change of colour in nails?

Black or dark nails can sometimes be linked to nutritional deficiencies, though this is less common than other causes such as trauma, fungal infections, or serious medical conditions, like melanoma. Nutritional deficiencies and some other factors or medications that might theoretically contribute to changes in nail color or health include:

1. Vitamin B12 Deficiency: While vitamin B12 deficiency is more commonly associated with changes in skin pigmentation and neurological symptoms, it can potentially lead to changes in nail color due to its role in DNA production and the health of blood cells.

2. Iron Deficiency: Iron deficiency, which can lead to anemia, might cause changes in nail shape (such as spoon nails) and possibly color. However, nails turning black due to iron deficiency alone is quite a rare condition; the nails might become pale or white, and in severe cases, there might be vertical streaks of darker color, but outright black nails are uncommon.

3. Protein Deficiency: Severe protein deficiency can affect the overall health of nails, leading to brittle nails or ridges, but direct causation of black nails is rare cases not typically noted.

Professional Treatments for Toenail Darkening

Darkened toenails can be caused by toenail fungal infections, which thrive in moist environments. To treat this, seek professional help from a podiatrist or a doctor. Antifungal medical treatment, either topical or with oral medication, can be used for mild cases. If the infection is resistant, laser therapy may be recommended. Additionally, if a nail is injured, such as a subungual hematoma, medical attention is needed to assess the injury and determine if intervention is necessary. It’s crucial to see a doctor and follow the prescribed treatment plan until the infection is completely gone.

Tips for Maintaining Healthy Toenails

Maintaining healthy toenails is crucial for preventing fungal infections and injuries. Regular foot hygiene, including washing and drying feet, is essential. Wearing breathable socks and changing socks daily can help prevent fungal growth. Trimming toenails short but not too short can prevent injuries and infections. Proper footwear, such as open-toed shoes or sandals, is essential for support. Be aware of changes in toenail color, texture, or thickness and seek professional advice if necessary. Early detection is key to treating nail problems.

Conclusion: Taking Care of Your Toenails and Seeking Professional Help

Darkening of toenails can be a cause for concern, but with the right knowledge and treatment, it can be effectively managed. Whether it’s a fungal infection or a nail injury, seeking professional help is crucial in accurately diagnosing the underlying condition or cause of black toenail and providing appropriate treatment options. Additionally, by following proper hygiene practices and maintaining healthy habits, you can reduce the risk of developing darkened toenails and other nail problems.

Remember, prevention is always better than cure. Take care of your toenails by practicing good hygiene, trimming them properly, wearing appropriate footwear, and monitoring any changes. If you notice any abnormalities or have concerns, don’t hesitate to seek professional advice. Your feet deserve the best care, and healthy, pink toenails are just a step away!

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