What causes thick, discolored toenails?

Thick, yellow-brown, or brittle toenails are most commonly caused by fungal infection (onychomycosis), affecting 10–14% of the population. Other causes include psoriasis, repeated microtrauma from tight shoes, peripheral vascular disease, and age-related changes. A podiatrist can clip a nail sample for lab analysis to confirm the diagnosis before recommending treatment.

How are ingrown toenails treated?

Mild ingrown toenails can sometimes be managed at home by soaking twice daily and placing a small piece of cotton under the corner. If there is pus, significant swelling, or the corner is deeply embedded, see a podiatrist. In-office treatment involves local anesthesia and removal of the offending nail border. For recurrent ingrown nails, phenol matrixectomy permanently prevents regrowth of that nail edge.

Can toenail changes be a sign of a systemic disease?

Yes. Nail pitting and separation suggest psoriasis; spoon-shaped nails suggest iron-deficiency anemia; yellow nails may indicate lymphedema or rheumatoid arthritis; splinter hemorrhages can indicate infective endocarditis. Diabetic patients frequently develop nail thickening from microtrauma and circulation changes. Podiatrists examine nails at every visit with systemic conditions in mind.

When should I see a podiatrist for a toenail problem?

See a podiatrist if a toenail is painful, infected, has changed color or thickness over months, is growing into the skin, or if you have diabetes and notice any nail change. Diabetic patients should never cut ingrown or thickened nails at home. Balance Foot & Ankle provides nail care in Howell and Bloomfield Hills — call (810) 206-1402.

What causes toenail onycholysis?

Common causes include trauma (from shoes), fungal infection (onychomycosis), psoriasis, thyroid disease, drug reactions (photosensitivity), and contact dermatitis. Pinching footwear causing repetitive microtrauma is the most frequent cause in active patients.

How do you treat onycholysis of the toenail?

Treatment targets the underlying cause. Traumatic onycholysis requires properly fitted footwear and nail trimming. Fungal onycholysis requires oral antifungal therapy. Psoriatic onycholysis responds to systemic psoriasis treatment. All cases benefit from keeping the separated nail trimmed short and dry.

Will a toenail with onycholysis grow back normally?

If the nail matrix is undamaged and the cause is eliminated, the nail typically reattaches as it grows out — a process taking 6–12 months. Permanent separation occurs when the nail bed is scarred or the underlying condition (psoriasis, chronic fungal) is not controlled.

Onycholysis of the Toenail: Why Nails Separate and How

Medically reviewed by Dr. Tom Biernacki, DPM

Board-certified podiatric surgeon | Balance Foot & Ankle, Howell & Bloomfield Hills, MI
Last reviewed: May 2026

MICHIGAN PODIATRIST INSIGHT

Onycholysis — the separation of the nail plate from the nail bed — looks like a simple nail problem but is actually a symptom of up to a dozen different underlying conditions, and treating only the nail without identifying the systemic cause leads to persistent recurrence. Call (810) 206-1402 — expert podiatric care across Michigan.

Onycholysis Toenail - Michigan podiatrist, Balance Foot & Ankle — Onycholysis Toenail treatment | Balance Foot & Ankle, Michigan

Onycholysis is the painless separation of the nail plate from the nail bed, beginning at the distal or lateral edge and progressing proximally. In the toenails, onycholysis produces a white, yellow, or green opaque area where the separated nail no longer receives nutrients from the nail bed. Trauma from ill-fitting footwear is the leading cause in podiatric practice, but onycholysis is also a nail manifestation of fungal infection, psoriasis, thyroid disease, and medications — particularly tetracyclines, fluoroquinolones, and taxane chemotherapy agents.

Causes of Toenail Onycholysis by Category

Category	Specific Cause	Distinguishing Feature	Treatment Focus
Traumatic	Repetitive microtrauma from shoe toe box; single acute subungual hematoma; excessive nail length	Distal onycholysis; hallux or 2nd toe most common; history of tight shoes or running	Proper shoe fit; nail trimming; nail avulsion if extensive
Fungal (onychomycosis)	Trichophyton rubrum; T. mentagrophytes; Candida (in immunocompromised)	Subungual debris; yellow-brown discoloration; nail thickening; distal-lateral onycholysis + KOH/culture positive	Oral antifungal (terbinafine 250mg x 12 weeks for toenails); laser antifungal adjunct
Psoriatic	Psoriatic nail disease; may precede skin psoriasis by years	Oil drop sign (salmon-colored patch beneath nail); nail pitting; hyperkeratosis; onycholysis often irregular	Dermatology referral; biologic therapy for moderate-severe; topical calcipotriol
Thyroid disease	Hyperthyroidism (Plummer nails); less commonly hypothyroidism	Lateral onycholysis with curved free edge; smooth separation without debris; other hyperthyroid signs	Treat underlying thyroid disease; onycholysis resolves with euthyroid state
Medication-induced	Tetracyclines (photo-onycholysis); taxane chemotherapy; fluoroquinolones; psoralens	History of medication; photo-onycholysis worst on sun-exposed digits; may be painful acutely	Discontinue causative drug; sun protection; nail regrowth over 6-12 months

Onycholysis Management Protocol

Step	Action	Rationale
1. Trim separated nail	Cut the onycholytic nail plate back to the point of separation; do not leave lifted nail attached	Attached separated nail is a use point for further trauma and traps moisture; secondary infection risk
2. Keep dry	Avoid prolonged water exposure; dry the nail space thoroughly after bathing; no nail polish over separated area	Moist onycholytic space grows Candida and Pseudomonas (green nail); dryness promotes reattachment
3. Address cause	Correct shoe fit; treat fungus; refer for psoriasis/thyroid workup; stop causative medication if possible	Nail will not reattach until the underlying cause is resolved
4. Patience	Toenail grows 1.5-2mm per month; full regrowth takes 12-18 months; do not force reattachment	The nail bed must regenerate normal onychodermal band attachment; cannot be accelerated

At Balance Foot & Ankle in Howell and Bloomfield Hills, onycholysis is evaluated with KOH preparation and culture when fungal onychomycosis is suspected, and systemic causes are considered when onycholysis is bilateral, progressive, or unresponsive to local treatment. Call (810) 206-1402.

American Academy of Dermatology: Nail Conditions

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For a complete clinical overview: Toenail Problems Complete Guide — nail discoloration, ridges, fungus, and injury treated

When should I see a podiatrist for a nail problem?

If your nail is thick, discolored, painful, or infected.

What causes nail discoloration?

Fungal infection is most common, followed by trauma and psoriasis.

Doctor Answer

What causes onycholysis of the toenail and how is it treated?

Onycholysis is separation of the toenail from the nail bed, often caused by trauma, fungal infection, psoriasis, or ill-fitting footwear. The separated area appears white or yellow and creates a space where debris and bacteria accumulate. Treatment involves identifying and addressing the underlying cause, keeping nails trimmed short, and avoiding moisture beneath the nail during healing.

— Dr. Tom Biernacki, DPM | Balance Foot & Ankle | Balance Foot & Ankle

Dr. Tom Biernacki, DPM

Dr. Tom Biernacki, DPM is a board-certified foot & ankle surgeon (ABFAS & ABPM) 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 made him one of the most-followed foot & ankle educators on YouTube.