Toenail Changes — What They Mean | Michigan Podiatrist

Quick answer:Toenail changes — thickening, discoloration, lifting, ridges, or a dark streak — can mean fungus, injury, psoriasis, or, rarely, melanoma. Our Michigan podiatrists diagnose the cause (sometimes with a quick nail test or biopsy), treat it, and evaluate any suspicious dark streak promptly. Book online, or call (810) 206-1402.

Medically reviewed by Dr. Tom Biernacki, DPM — Board-Certified Podiatric Surgeon — Balance Foot & Ankle, Howell & Bloomfield Township, MI. Last updated April 2026.

Your toenails tell a story. Changes in toenail color, thickness, texture, or attachment can be cosmetically concerning, occasionally painful, and sometimes a signal of a serious underlying condition. At Balance Foot & Ankle, Dr. Tom Biernacki evaluates toenail changes with a clinician’s eye — distinguishing between common benign conditions and the rare but important findings that require additional investigation.

Yellow or Discolored Toenails

Most likely cause: Onychomycosis (fungal nail infection) — Yellow, brown, white, or orange discoloration with nail thickening is almost always fungal. Dermatophyte fungi invade the nail plate, causing progressive discoloration, crumbling, and thickening. Diagnosis is confirmed by nail clipping culture or PAS stain — not just visual appearance alone. Treatment options include topical antifungals (Jublia, Kerydin), oral terbinafine or itraconazole (most effective), or laser nail treatment. A confirmed positive culture before starting oral medication is medically sound practice.

Other causes of yellow nails: Yellow nail syndrome (associated with lymphedema and respiratory conditions); psoriatic nails (yellow-orange discoloration with pitting); prolonged use of certain medications; or simply staining from nail polish.

Black or Dark Toenails

Most likely cause: Subungual hematoma — A bruise under the nail from trauma (dropping something on the foot, running in tight shoes) causes blood to pool under the nail plate, appearing black or dark purple. Most hematomas resolve over weeks as the nail grows out. Large, painful hematomas can be drained by piercing the nail plate (trephination) for immediate relief. Always confirm the black discoloration is a hematoma and not melanoma.

Important: Subungual melanoma — Dark pigmentation under the nail that cannot be attributed to trauma requires urgent evaluation to rule out subungual melanoma — a rare but serious skin cancer. Features raising concern: dark streak in the nail (melanonychia) that is widening, has irregular borders, or is accompanied by pigmentation on the surrounding skin fold (Hutchinson’s sign). Any unexplained dark nail stripe warrants a biopsy referral.

Thick or Distorted Toenails

Fungal infection (onychomycosis) is again the most common cause of nail thickening. Other causes: onychogryphosis (ram’s horn nail) — extreme nail curvature and thickening from repeated trauma or poor nail hygiene, common in elderly patients; subungual exostosis — a bone spur growing under the nail causes the nail to lift and distort; psoriasis — produces pitting, onycholysis, and subungual hyperkeratosis (thickening under the nail).

Lifting or Separating Toenails (Onycholysis)

Separation of the nail plate from the nail bed can be caused by fungal infection, trauma, psoriasis, thyroid disease, medication side effects (especially certain chemotherapy agents, tetracyclines, and quinolone antibiotics), or simply from wearing nail polish long-term. The separated nail provides a dark, moist space where secondary bacterial infections can occur. Trimming the separated nail back and keeping the area dry is important while the underlying cause is treated.

White Spots on Toenails

Small white spots (leukonychia punctata) are usually harmless — caused by minor nail matrix trauma (bumping the nail during growth). They grow out with the nail over weeks. Diffuse whitening of the entire nail can indicate systemic conditions including liver disease, kidney disease, or hypoalbuminemia and warrants evaluation.

Get Your Toenails Evaluated in Michigan

Don’t ignore toenail changes — most are treatable and some warrant urgent evaluation. Balance Foot & Ankle provides expert toenail evaluation and treatment at southeast Michigan offices. Call (810) 206-1402 to schedule with Dr. Biernacki.

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Visit Balance Foot & Ankle — Same-Week Appointments Available

Our podiatry team serves patients throughout Michigan including Howell, Brighton, and Bloomfield Township. If you’re dealing with heel pain, ingrown toenails, or a foot injury, we have same-week appointment availability.