What's Causing Black Spots Under My Toenails? - Causes & Treatment

Understanding Black Spots Under Your Toenails

Noticing black, brown or dark discoloration under your toenails can be alarming. However, several common conditions can cause this besides just fungal infections. Learning whats behind black spots under your nails empowers you to seek proper treatment.

Possible Causes

Here are some potential reasons you may be experiencing dark pigmentation under the nail:

Toenail Fungus

One of the most common causes of black dots or streaks on the nail is a fungal infection. Fungus causes nails to thicken, become brittle and dark fragments develop.

Melanonychia

Darker skin pigment (melanin) collecting under the nail causes grey, brown or black linear streaks called melanonychia. This is harmless in many cases.

Bruising

Trauma like stubbed toes can rupture small blood vessels under the nail, resulting in reddish-black bruise-like spots as blood pools.

Subungual Hematoma

A subungual hematoma is a collection of blood trapped under the nail after significant trauma. This causes throbbing pain and a dark red or purple spot.

Skin Cancer

Rarely, dark streaks/spots under a nail may signal certain forms of skin cancer like melanoma. Sudden nail changes warrant inspection.

Diagnosing the Cause of Black Marks Under Nails

Figuring out whether toenail fungus or something more serious is behind your nail discoloration is key. Heres how your doctor will evaluate:

Medical History

Your doctor will ask about potential trauma, family history of skin cancer, risk factors like frequent tanning bed use, and any other symptoms like pain or changes to surrounding skin.

Physical Exam

They will closely inspect the appearance, shape and texture of darkened nails and note whether one or both feet are involved. Other nail irregularities may provide clues.

Microscopy

Scrapings from under the nail can be examined under a microscope to identify fungal hyphae or atypical skin cells if melanoma is suspected.

Biopsy

For persistent changes where cancer is a concern, your doctor may opt to take a small nail clipping for biopsy. This can definitively diagnose or rule out malignancy.

Treating Common Causes of Toenail Dark Spots

Treatment will depend on the underlying cause but may include:

Antifungal Medication

For fungal infections, oral medications like terbinafine or topical creams may be prescribed to eliminate fungus and allow healthy nail regrowth.

Nail Removal

In some cases, the affected part or entire toenail may need to be surgically removed to resolve fungal/skin cancer issues before re-growth.

Cryosurgery

For dark streaks from melanonychia, carefully freezing affected areas can lighten color. Several treatments may be needed.

Laser Therapy

Using a laser to selectively target and break up excess pigment may reduce dark spots from melanonychia over a series of treatments.

Monitoring

If biopsy confirms streaks are benign melanonychia, ongoing monitoring for changes may be all thats needed.

When to See Your Doctor

Seek medical evaluation if you notice:

• Sudden nail darkening/discoloration
• Pain, swelling, discharge or bleeding around nail
• Nail dark streak changing in appearance
• Discoloration spreading to other nails
• Family history of melanoma
• Dark spot after nail trauma

Preventing Black Spots Under Toenails

You can reduce risks of future nail pigmentation problems with these measures:

Practice Nail Hygiene

Keep toenails trimmed straight across and avoid picking at nails to prevent trauma. Wear shower shoes in public areas.

Treat Athletes Foot

Since fungus spreads from infected skin, use antifungal spray/powder on feet and wear moisture-wicking socks.

Disinfect Nail Tools

Properly clean and disinfect any nail clippers, files and pedicure tools between uses to avoid spreading infections.

Avoid Nail Damage

Wear properly fitted shoes to prevent toenail bruising or injury during sports and exercise.

Apply Nail Sunscreen

Use broad spectrum sunscreen on feet during extended sun exposure to protect nails from UV damage.

When Black Toenail Marks Warrant Concern

Dark blotches under a nail are usually harmless, but see a dermatologist promptly if:

• Lines run lengthwise down the entire nail in a narrow band
• Streaks increase in width, become irregular, or fade in and out
• You have a family/personal history of skin cancer
• Discoloration spreads to other nails or skin
• You experience nail separation, throbbing pain, oozing

In these cases, prompt medical evaluation is recommended to determine if biopsy or other testing is warranted.

Seeking Help for Toenail Changes

Dont ignore changes to your toenail appearance. Dark spots under nails may simply be bruising, but they can sometimes indicate an underlying fungal infection or serious condition like melanoma. Getting them checked out provides peace of mind and allows quick treatment if needed.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.