We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is Melanonychia?

By Maggie J. Hall
Updated Mar 03, 2024
Our promise to you
The Health Board is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At The Health Board, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Melanonychia refers to a band of brown or black discoloration of finger or toe nails. The condition may be benign or indicative of a type of cancer. Certain non-cancerous medical conditions may cause the abnormality, along with some medications. Health care providers usually require a complete medical history and a physical assessment to rule out possible contributing factors.

Discoloration usually develops longitudinally, running from the cuticle to the tip of the nail. The cuticle may or may not be included in the coloration. The bands or stripes associated with this condition may appear as a single line or completely cover the nail. The forefinger, thumb and great toe are the most common sites of the affliction but more than one digit may be involved.

The band may appear as one solid color or graduate from one shade of brown to another. Thin, regular or irregular lines sometimes appear. The line of coloration may have parallel borders or be irregular. Symptoms may also appear as purplish blue to brown dots or blotches of dried blood beneath the nail.

Abnormally large deposits of melanin often occur in the nails of people who have dark skin. Studies indicate that 77% of individuals of African descent experience melanonychia. The condition may also occur in people of Asian heritage 10% to 20% of the time. Only 1% of people with Caucasian ancestry experience this cutaneous condition.

Trauma to fingers or toes commonly produces nail discoloration, and bacterial and fungal infections may also cause melanonychia. Many medical conditions, including Addison's disease and psoriasis, produce nail discoloration. The rare syndrome known as Langier-Hunziker typically causes oral hyperpigmentation, and individuals that have this acquired disorder may also develop excess coloration under finger or toenails.

Side effects associated with chemotherapy, radiation, and warfarin can cause melanonychia. Other medications that might contribute to abnormal pigmentation are hydroxyurea, minocycline, and zidovudine. The discoloration generally subsides once treatment ends or causative medications are no longer required.

Melanonychia can also indicate a serious type of skin cancer. Left undiagnosed and untreated, the malignancy can metastasize to the bone, central nervous system, and body organs. Physicians may perform a biopsy to identify possible malignant cells associated with melanoma.

Dermatologists suspecting malignancy can obtain samples by shaving a thin layer of tissue. Physicians can also access tissue by punch biopsy or surgical excision. A positive malignant diagnosis generally requires the affected area undergo surgical removal.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Discussion Comments

By Pippinwhite — On Feb 09, 2014

I'd never heard of cancer showing up as a dark streak on the fingernail. The scary part is the part about "the affected area may be removed." That means losing a finger. Not a pleasant thought.

I have thyroid issues and can track how well my medication is working by the vertical ridges on my thumbnails. When the ridges start becoming pronounced, it's time to adjust my meds, usually by increasing them.

It's just another bit of evidence that a lot can be learned about a person's overall health by looking at their fingernails. Certainly, it's something to be aware of.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.