| Condition | Appearance | Pain Level | X-ray | Key Distinguishing Test |
|---|---|---|---|---|
| Subungual Hematoma | Dark red, purple, or black blood beneath nail plate; may be partial or complete | Throbbing pain proportional to hematoma size and pressure | Normal bone (unless associated fracture) | Hematoma blanches or fluid shifts on pressure; resolves as nail grows out |
| Subungual Melanoma | Dark longitudinal streak (melanonychia) → irregular pigment spreading to nail fold (Hutchinson sign) | Often painless until advanced | Possible bone destruction in late stages | Hutchinson sign (pigment on proximal nail fold) = biopsy urgently |
| Subungual Exostosis | Nail lifted; discolored from bony mass beneath; not blood-filled | Pressure pain; chronic | Bony spur on distal phalanx | X-ray shows bony projection; nail lifting without hematoma |
| Onychomycosis | Yellow-brown-black; thickened, crumbling nail; chronic course | Minimal unless subungual debris is thick | Normal bone | KOH prep or fungal culture; months of discoloration without trauma history |
| Nail Matrix Nevus | Brown-black longitudinal streak; present since childhood or stable for years | Painless | Normal | Dermoscopy; biopsy if changing; stable lesions observed |
| Hematoma Size | Nail Plate Status | Fracture? | Treatment | Expected Outcome |
|---|---|---|---|---|
| <25% nail plate involved | Intact; adherent | No | Observation; pain management; protective shoe | Resolves as nail grows out in 6–9 months |
| 25–50% with significant pressure pain | Intact or partially detached | No | Nail trephination (heat cautery or 18g needle) to drain; immediate pain relief | Pain relief within minutes; nail usually retained and grows out |
| >50% nail plate involved | Partially detached | No | Trephination or nail avulsion for complete drainage; irrigate | Nail may be lost; regrowth in 9–12 months (hallux) |
| Any size with distal phalanx fracture | Variable | Yes | Nail avulsion; fracture irrigation and reduction; nail plate replaced as biological dressing | Wound protection; fracture alignment; nail regrowth expected |
| Nail plate avulsion with crush injury | Avulsed or lacerated | Possible | Nail bed laceration repair; fracture management; tetanus | Nail matrix repair critical for cosmetic regrowth |
A black toenail (subungual hematoma) after running, hiking, or trauma usually heals on its own — but if pressure builds up enough to cause throbbing pain, drainage relieves it dramatically.
You’re in the right place. Dr. Tom Biernacki, DPM, FACFAS — board-certified foot & ankle surgeon with 3,000+ surgeries — explains exactly what subungual hematoma (black toenail) means and what works. Call (810) 206-1402 for same-day appointment at Howell or Bloomfield Hills.
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Quick Answer:
Quick Answer: A subungual hematoma is blood accumulation under the toenail from direct trauma — causing the nail to appear black or dark purple and producing intense throbbing pressure pain. Trephination (creating a small hole through the nail to drain the blood) provides immediate pressure relief when performed within 24-48 hours. Black toenail in runners from repeated microtrauma (runner’s toe) resolves with nail loss and regrowth. Any painless black nail discoloration without clear trauma history requires evaluation to rule out subungual melanoma.
A subungual hematoma — blood collecting beneath the toenail after trauma — is one of the most acutely painful foot injuries. The enclosed space under the hard nail plate allows blood to accumulate under pressure, causing intense throbbing pain disproportionate to the initial injury. At Balance Foot & Ankle PLLC, Dr. Tom Biernacki provides prompt trephination (pressure-relief drainage) and evaluates all nail discoloration to ensure that melanoma is not mistaken for benign trauma.
Traumatic Subungual Hematoma
Mechanism: direct crush injury (dropped object, stubbed toe) or repeated microtrauma (runner’s toe from repetitive nail impact in the shoe). Acute presentation: dark red-to-black nail discoloration, severe throbbing pressure pain, potential nail plate separation from the nail bed. Trephination for acute traumatic hematoma: Creating a small perforation through the nail plate (using a heated wire or rotary tool) allows the hematoma to drain — immediate, dramatic pain relief. Most effective within 24–48 hours. After drainage, the nail may or may not separate — if it does, it will regrow over 6–9 months. Associated distal phalanx fracture present in up to 50% of large hematomas — X-ray evaluation.
Runner’s Toe (Chronic Repetitive Hematoma)
Runner’s toe — chronic repetitive microtrauma from the nail impacting the shoe toe box during downhill running or with tight footwear — creates repeated subungual hemorrhage without acute traumatic event. The nail gradually darkens, separates, and eventually falls off. A new nail regrows underneath. Management: correct the causative footwear issue — ensure adequate thumb’s-width space from the end of the longest toe to the shoe tip. If it is the second toe that is longest, standard shoe sizing (based on big toe) creates second toe compression. Toe socks and nail trimming. Running gait analysis.
When Black Toenail Requires Biopsy
Any black nail without clear traumatic history requires evaluation to rule out subungual melanoma — a rare but serious pigmented lesion that can appear beneath the nail. Red flags: painless longitudinal brown-black streak (melanonychia) extending from the nail matrix, Hutchinson’s sign (pigment spreading to the cuticle or skin adjacent to the nail), single nail involvement without trauma history, age over 50, and failure to improve after nail regrowth. Biopsy of the nail matrix confirms or excludes melanoma in ambiguous cases.
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Ensure thumb’s-width space in front of longest toe — have feet sized at end of day
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✅ Pros / Benefits
- Trephination provides immediate, dramatic pain relief when performed promptly
- Runner’s toe reliably resolves with footwear correction — preventable condition
- Distal phalanx fracture identification on X-ray prevents missed associated injury
- Subungual melanoma distinction from trauma prevents delayed cancer diagnosis
❌ Cons / Risks
- Nail will likely separate and regrow over 6-9 months after significant hematoma
- Runner’s toe recurs until the causative footwear issue is corrected
- Subungual melanoma biopsy is necessary when clinical features are ambiguous
Dr. Tom Biernacki’s Recommendation
Subungual hematoma trephination is one of the most immediately gratifying procedures in podiatry — the patient is in severe throbbing pain, I make a small hole in the nail, and the dark blood drains with immediate complete pain relief. The patient’s expression of relief is always memorable. The more important clinical skill is recognizing when a black nail is not traumatic — longitudinal melanonychia without a history of trauma is a red flag for nail melanoma that needs biopsy.
— Dr. Tom Biernacki, DPM | Board-Certified Podiatric Surgeon | Balance Foot & Ankle
Frequently Asked Questions
Should I drain a blood blister under my toenail?
If you have acute severe pressure pain and a dark nail from a clear traumatic event (dropped something on toe, stubbed toe), trephination can be performed in our office to drain the hematoma and relieve pressure — most effective within 24-48 hours. Do not attempt self-trephination with needles or sharp objects — risk of infection and incomplete drainage. If the nail is not acutely painful, observation and natural nail separation is appropriate.
Will my toenail fall off after a subungual hematoma?
Whether the nail separates depends on the extent of the hematoma. Large hematomas (covering more than 50% of the nail) typically result in nail-bed separation and nail loss. The nail plate separates painlessly over weeks and falls off — a new nail grows underneath over 6–9 months. The nail bed and nail matrix are almost always intact, and regrown nails are typically normal in appearance.
Why do runners lose toenails?
Runner’s toe — chronic repetitive nail trauma from the nail impacting the shoe toe box with each stride — particularly on downhill running. The nail accumulates subclinical hemorrhage over time, eventually losing attachment and falling off. Causes: shoe too small (no thumb-width space in front of longest toe), second toe longer than big toe (creating second toe compression with standard sizing), downhill running mechanics. Prevention: correctly sized shoes with wide toe boxes and adequate length.
What is subungual melanoma?
Subungual melanoma is a rare but serious melanoma arising from the nail matrix or nail bed — appearing as a longitudinal brown or black streak (melanonychia striata) under the nail, or as diffuse nail discoloration without trauma history. It accounts for up to 33% of melanomas in darker-skinned patients. Hutchinson’s sign — pigment spreading from under the nail to the surrounding skin — is a high-risk feature. Any painless longitudinal nail pigmentation that is new, widening, or present in a single nail without trauma history requires evaluation and potential biopsy.
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How long does it take a toenail to grow back?
6-12 months for a full big toenail. Smaller toenails 4-6 months. Speed varies with age, circulation, and nutrition.
Will this affect other nails?
Trauma affects only the injured nail. Fungal infection can spread without treatment. Systemic causes affect multiple nails simultaneously.
Should I cover the nail or leave it open?
Cover with a breathable bandage during work or activity. Leave open at night for healing. Keep dry and clean.
Foot pain typically responds best to early podiatrist evaluation, conservative treatments such as supportive footwear and targeted physical therapy, and—when needed—custom orthotics or in-office procedures. Most patients see meaningful improvement within 4-6 weeks of starting a structured treatment plan. Schedule an evaluation at our Howell or Bloomfield Hills office for a clinical assessment.
What is Foot pain?
Foot pain is a common foot/ankle condition that affects mobility and quality of life. Understanding the underlying cause is the first step in successful treatment. Our podiatrists at Balance Foot & Ankle perform a hands-on biomechanical exam, review your activity history, and use diagnostic imaging when appropriate to identify the root cause—not just treat the symptom. Many patients have been told to “rest and ice” without a deeper diagnostic workup; our approach is different.
Symptoms and warning signs
Common signs of foot pain include pain that worsens with activity, morning stiffness, swelling, tenderness when palpated, and difficulty bearing weight. If you experience sudden severe pain, inability to walk, visible deformity, numbness or color change, contact our office the same day or visit urgent care—these can signal a more serious injury such as a fracture, tendon rupture, or vascular compromise. Diabetics with any foot wound should seek same-day care.
Conservative treatment options
Most cases of foot pain respond to non-surgical care: structured rest, supportive footwear changes, custom orthotics, targeted stretching and strengthening protocols, anti-inflammatory medications when medically appropriate, and in-office procedures such as ultrasound-guided injections. We also offer advanced therapies including MLS laser therapy, EPAT/shockwave, regenerative injections, and image-guided procedures. Treatment is sequenced from least invasive to most invasive, and we explain the rationale at every step.
When is surgery considered?
Surgery is reserved for cases that fail 3-6 months of well-structured conservative care, when there is structural pathology (severe deformity, complete tear, advanced arthritis), or when imaging shows damage that will not heal without intervention. Our surgeons have performed 3,000+ foot and ankle procedures and prioritize minimally-invasive techniques whenever appropriate. We discuss recovery timelines, return-to-activity milestones, and realistic outcome expectations before any procedure is scheduled.
Recovery timeline and prevention
Recovery from foot pain varies based on severity and chosen treatment path. Conservative cases often improve within 4-8 weeks with consistent adherence to the protocol. Post-procedural recovery may range from a few days (in-office procedures) to several months (reconstructive surgery). Long-term prevention involves footwear assessment, activity modification, structured strengthening, and regular check-ins with your podiatrist if you have a history of recurrence. We provide written home-exercise plans and digital follow-up support.
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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.
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