What Causes Toenail Fungus: Types and Onychomycosis | DPM

Quick answer:Toenail fungus (onychomycosis) is caused by dermatophyte fungi — and sometimes yeasts or molds — that enter through tiny cracks and thrive in warm, damp shoes, leaving nails thick, yellow, and brittle. It comes in several types, and a podiatrist can identify which and treat it effectively. Call (810) 206-1402.

✅ Medically reviewed by Dr. Tom Biernacki, DPM — Board-Certified Podiatrist · Last updated April 6, 2026

What Causes Toenail Fungus & Onychomycosis? [Types of Toenail Fungus]

What Causes Toenail Fungus & Onychomycosis? [Types of Toenail Fungus] 🦶We review the TRUE Causes of toenail fungus and onychomycosis. We also review the types of toenail fungus.🦶 Related Videos: Athlete’s Foot Fungus Treatment: https://youtu.be/PKT_slq6M54 Toenail Fungus Treatment: https://youtu.be/Uq30wM7YSAM Best Diabetes Drink: https://youtu.be/YOFrlc10E4E Reverse 90% of Diabetes with this Diet: https://youtu.be/qCQW9e7CrEk 10 Best Diabetic Vitamins: https://youtu.be/sPihveT3oc0 Best Diabetic Foods: https://youtu.be/jLID96VA7j0 29 Worst Foods for Clogged Arteries: https://youtu.be/bZKQEp2AHfc How to know your heart is not well: https://youtu.be/qx4QAX2L4Fo Vitamin D, Vitamin K2 & Magnesium: https://youtu.be/esTz-_Mpm4Q Reverse Clogged Arteries: https://youtu.be/oNiZo0nO048 Diabetic Neuropathy [Peripheral Neuropathy]: https://youtu.be/E_0ALrqYUSM 👉 LINKS 👈 Disclaimer: This video and description contain affiliate links, which means we may receive a commission if you click on one of the product links. Best Socks for Toenail Fungus:

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Athlete’s Foot Fungus Treatment Products: Lotrimin Ultra Athlete’s Foot Cream: https://geni.us/K6D7XN (Amazon) Athlete’s Foot Spray: https://geni.us/H3tk14Z (Amazon) Tea Tree Oil Kit: https://geni.us/ZDR4 (Amazon) Tough Actin Tinactin Cream: https://geni.us/Ri3S5 (Amazon) Athlete’s Foot Power: https://geni.us/e058wP (Amazon) Best Toe Nail Fungus Treatment [Onychomycosis treatments] Toenail fungus Extra Strength Application: https://geni.us/TjZuwY (Amazon) Toenail fungus application pen: https://geni.us/0du8 (Amazon) Vicks Vaporub: https://geni.us/zHdX (Amazon) Listerine: https://geni.us/iSoFdA (Amazon) Kerasol Nail Restoration: https://geni.us/ZjdPuH (Amazon) Nail Fungus & Foot Fungus Combo pack: https://geni.us/tA74KAq (Amazon) Toenail fungus, also known as onychomycosis, is a common fungal infection that affects the nails of the toes. It is caused by several fungi, including dermatophytes, yeasts, and molds. The fungus thrives in warm, moist environments and can quickly spread from person to person in shared public spaces such as locker rooms and showers. Some of the risk factors that can increase the likelihood of developing toenail fungus include: Age, Gender, Genetics & most importantly Health conditions. Trauma: Injuries to the toenail or nail bed can increase the risk of developing toenail fungus. There are several types of toenail fungus, including: Distal subungual onychomycosis: This is the most common type of toenail fungus and affects the nail bed and underside of the nail. White superficial onychomycosis: This type of toenail fungus affects the surface of the nail, causing white patches or streaks. Proximal subungual onychomycosis: This type of toenail fungus affects the base of the nail, near the cuticle. Total dystrophic onychomycosis: This type of toenail fungus causes the nail to thicken and separate from the nail bed, eventually falling off. 👉 Shoes 👈 Best Shoes:

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Best Products: https://www.michiganfootdoctors.com/recommended-foot-doctor-products/// 📢Come See Us in Detroit, Michigan, Berkley Michigan; Bloomfield Township, Michigan, Lansing Michigan; and Grand Blanc Michigan📢 If you are in Michigan, consider seeing us at our clinic: https://www.michiganfootdoctors.com/. https://g.page/r/CaxJ9b-O6o27EAE 👉 LINKS 👈 Disclaimer: This video and description contain affiliate links, which means we may receive a commission if you click on one of the product links. I appreciate your support of this channel! DISCLAIMER: Dr. Tomasz Biernacki received his Doctor of Podiatric Medicine degree from Kent State College of Podiatric Medicine in 2013; he completed his Surgical Reconstructive Foot Surgery & Podiatric Medicine Residency in 2017; he completed 2 separate traveling Fellowships in Diabetic Surgery, Skin Grafting & Nerve Surgery. He is double board certified in Podiatric Medicine and separately in Foot & Ankle Surgery. His use of “doctor” or “Dr.” about himself solely refers to that degree. Dr. Biernacki is a licensed podiatrist in Michigan. This video is for general informational purposes only. It should not be used to self-diagnose and is not a substitute for a medical exam, cure, treatment, diagnosis, prescription, or recommendation. It does not create a doctor-patient relationship between Dr. Biernacki and you. It would be best if you did not change your health regimen or diet before consulting a physician and obtaining a medical exam, diagnosis, and recommendation. Always seek the advice of a physician or other qualified health provider with any questions regarding a medical condition.

Michigan Podiatric Care at Balance Foot & Ankle: Expert Treatment for Every Foot Condition

Michigan patients with any foot or ankle concern — from acute injuries and chronic pain to preventive care and high-risk foot management — receive expert podiatric care at Balance Foot & Ankle. Our fellowship-trained podiatrists provide hands-on exam plus imaging when needed, accurate diagnosis, and evidence-based treatment that addresses root causes rather than simply managing symptoms. We are committed to transparent communication: patients always understand their diagnosis, their treatment options, and realistic expectations before any intervention is undertaken.

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Related Treatment Guides

• Toenail Treatment
• Plantar Fasciitis & Heel Pain Treatment
• Custom 3D Orthotics
• Sports Foot & Ankle Injury Treatment

Our Howell office (4330 E Grand River) serves Livingston County, and our Bloomfield Township office (43494 Woodward Ave #208) serves Oakland County. Both locations offer in-office X-ray, new patient scheduling, and the full range of conservative and surgical podiatric services. We accept all major Michigan insurance plans and verify coverage before appointments — no insurance surprises at check-in. Michigan patients ready to take the next step toward better foot health can call Balance Foot & Ankle at (810) 206-1402 to schedule today.

In-Office Treatment at Balance Foot & Ankle

If home treatment isn’t providing relief for your toenail fungus, our podiatry team at Balance Foot & Ankle can help with expert evaluations and advanced in-office care.

Frequently Asked Questions

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.

More questions patients ask

What are the main causes of toenail fungus?

Toenail fungus (onychomycosis) is caused by dermatophytes (fungi that infect keratin) in 80–90% of cases — primarily Trichophyton rubrum. Less common causes: yeasts (Candida species — often in fingernails, associated with chronic wet work) and non-dermatophyte molds (Fusarium, Scopulariopsis, Aspergillus). The infection pathway: dermatophytes from the environment or skin enter the nail through micro-trauma or from pre-existing athlete's foot, colonize the nail plate and nail bed, and gradually spread. Risk factors: advancing age (slower nail growth, reduced immunity), diabetes, poor circulation, athlete's foot, immunosuppression, tight footwear, excessive sweating, communal bathing facilities, and nail trauma. Balance Foot & Ankle (810) 206-1402 — Howell and Bloomfield Township.

What are the different types of toenail fungus?

Onychomycosis has four main clinical patterns: 1) Distal and lateral subungual onychomycosis (DLSO) — most common; infection begins at the free nail edge and spreads toward the root, causing yellowing, thickening, and separation. 2) Superficial white onychomycosis (SWO) — infection on the nail surface causing white, powdery patches; more common in children and immunocompromised patients. 3) Proximal subungual onychomycosis (PSO) — infection enters under the proximal nail fold and spreads outward; rare in immunocompetent adults, strongly associated with HIV. 4) Total dystrophic onychomycosis (TDO) — end-stage destruction of the entire nail; secondary to any of the above. Identifying the type guides treatment planning at Balance Foot & Ankle.

Why do older adults get more toenail fungus?

Multiple age-related factors increase toenail fungus risk: slower nail growth (means longer exposure to fungal penetration per unit nail length), reduced peripheral circulation (less antifungal drug delivery to nail bed), accumulated micro-trauma over decades (more nail damage creating entry points), longer cumulative exposure to contaminated environments, reduced immune function (less effective anti-fungal cellular immunity), higher prevalence of comorbidities (diabetes, PAD), increased use of communal facilities (gyms, nursing homes, pools), and medications that suppress immunity. The prevalence of onychomycosis increases from ~3% in young adults to 20–30% in those over 60. Regular professional nail care at Balance Foot & Ankle becomes increasingly important for older patients.

Can nail trauma cause toenail that looks like fungus?

Yes — traumatic nail dystrophy (onychodystrophy) from chronic repetitive microtrauma mimics onychomycosis closely: thickening, discoloration (brown, yellow), brittleness, and nail separation. Common sources of traumatic nail injury: poorly fitting shoes (nails hit the toe box repeatedly during walking or running), sports activities (runner's toenail), barefoot walking on hard surfaces, heavy objects dropped on toes, and previous nail avulsion. The key difference: traumatic dystrophy won't respond to antifungals. A KOH scraping and nail culture at Balance Foot & Ankle definitively distinguishes fungal from traumatic nail disease — this diagnostic step prevents years of unnecessary antifungal treatment. Many 'toenail fungus' cases in active patients are actually traumatic dystrophy.

How does athlete's foot lead to toenail fungus?

Athlete's foot (tinea pedis) and onychomycosis are intimately connected: the same dermatophyte fungi (primarily T. rubrum) cause both conditions. The infection pathway: T. rubrum establishes in the interdigital skin (between toes), and with time, migrates from the skin to the adjacent nail via the hyponychium (the junction where the nail plate meets the nail bed) or through the lateral nail fold. Studies show that untreated athlete's foot dramatically increases onychomycosis incidence. Conversely, successfully treating toenail fungus while leaving athlete's foot untreated leads to rapid nail reinfection — both conditions must be treated simultaneously for lasting cure. At Balance Foot & Ankle, we always assess and treat both conditions together. Call (810) 206-1402.

What is the best treatment for toenail fungus?

Oral antifungal medication has 70-80% cure rate. Laser therapy and topicals work for milder cases. Dr. Biernacki creates individualized plans based on severity. Treatment takes 3-6 months. Call 810-206-1402.

Is toenail fungus contagious?

Yes, it spreads through direct contact and contaminated surfaces. High-risk: pools, gym showers, locker rooms. Wear shower shoes, keep feet dry, use antifungal powder, don't share nail tools.

How do I know if I have toenail fungus?

Signs: yellowing/whitening, thickening, crumbling edges, separation from nail bed, foul odor. Professional diagnosis recommended as it can be confused with nail psoriasis or trauma.

Still have a question about coverage or cost? Book online and we will check your benefits before your visit: Book in Howell · Book in Bloomfield Township. Prefer to talk it through first? Call (810) 206-1402.