What is Black Toenail?

Black Toenail (subungual hematoma) is bruising under the toenail caused by repeated trauma during running. It's so common among distance runners that it's often called a "badge of honor."

What Causes It?

Primary Cause: Repetitive Trauma

Your toes repeatedly hit the front or top of your shoe during:

• Downhill running
• Long distances
• Speed work
• Hot weather (feet swell)

Contributing Factors

The Progression

Stage 1: Redness/Soreness
    ↓
Stage 2: Purple/Blue Discoloration
    ↓
Stage 3: Black Toenail
    ↓
Stage 4: Nail Loosening
    ↓
Stage 5: Nail Falls Off 😱
    ↓
Stage 6: New Nail Grows (3-6 months)

Treatment Options

At Home

1. Ice - Reduce swelling immediately after run
2. Elevate - Keep feet up when possible
3. Protect - Bandage loose nails
4. Wait - Most resolve on their own

When to See a Doctor

• Severe pain
• Signs of infection (pus, red streaks, fever)
• Nail completely detached with open wound
• Recurring issues

Draining (Not Recommended DIY)

Some runners (and doctors) drain blood by:

• Heated paperclip through nail
• Sterile needle

⚠️ Risk of infection — better left to professionals!

Prevention Strategies

Shoe Fit

✅ Thumb's width between longest toe and shoe end
✅ Try shoes on in afternoon (feet swell)
✅ Size up for long races/hot conditions

Toenail Care

✅ Trim nails straight across, not too short
✅ File sharp edges
✅ Check before long runs

Socks & Lacing

✅ Moisture-wicking socks
✅ Heel-lock lacing to prevent sliding
✅ Double-layer socks for ultras

Runner's Perspective

Lost my first toenail after my first marathon. Now I consider them optional. — Every marathoner, probably

Some runners even embrace black toenails:

• Proof of training dedication
• War stories to share
• Rite of passage into serious running

Fun Facts

• The average ultramarathoner loses 2-3 toenails per year
• Toenails grow about 3mm per month
• A completely lost nail takes 6-12 months to fully regrow
• The big toe is most commonly affected

Remember: A black toenail won't end your running career — but proper shoe fit can prevent most of them!