/ CONDITIONS / FUNGAL TOENAILS
Fungal Toenails
Thickened, discolored, or crumbly toenails are not always caused by fungus — accurate diagnosis is the essential first step toward effective treatment.
Dr. Andrew Gunter, DPM — San Antonio, TX.
Call (210) 581-9800
Fungal Nails vs. Nail Dystrophy —
Why the Distinction Matters
Fungal toenails — medically termed onychomycosis — are caused by a dermatophyte, yeast, or non-dermatophyte mold infection of the nail bed and nail plate. The infection produces characteristic changes: thickening of the nail plate, yellowing or browning discoloration, crumbling or brittle nail texture, separation of the nail from the nail bed, and sometimes a foul odor. Onychomycosis is common — affecting an estimated 10 percent of the general population and up to 50 percent of adults over 70 — and it does not resolve without treatment.
However, thickened, discolored, or crumbly toenails are not always caused by fungal infection. Nail dystrophy — structural nail changes from non-infectious causes — can produce a presentation that is visually identical to onychomycosis. The most common causes of nail dystrophy that mimic fungal nail include:
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Repetitive microtrauma: Runners, hikers, and anyone whose toes repeatedly contact the front of the shoe develop nail changes over time from cumulative impact. Thickening, discoloration, subungual hematoma, and nail separation can all result from mechanical trauma rather than infection. This is one of the most commonly missed diagnoses in patients told they have nail fungus.
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Acute nail trauma: A single significant nail injury — dropping something on the toe, stubbing against a hard surface — can produce permanent nail changes including thickening, ridging, and discoloration that persist indefinitely.
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Psoriasis: Nail psoriasis produces pitting, onycholysis, oil drop discoloration, and subungual hyperkeratosis — changes that strongly overlap with onychomycosis both visually and under basic microscopy.
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Lichen planus: This inflammatory condition can cause significant nail dystrophy including thinning, ridging, and pterygium formation.
The clinical significance of this distinction is direct: antifungal treatment — whether topical or oral — produces no benefit for nail dystrophy. Treating a traumatically dystrophic nail with months of oral antifungals is not only ineffective but exposes the patient to unnecessary medication and cost. The only reliable way to distinguish onychomycosis from nail dystrophy is through clinical assessment combined with laboratory confirmation — nail culture or KOH preparation — before initiating treatment.
Dr. Gunter evaluates nail changes thoroughly before recommending any treatment, confirming the diagnosis when appropriate rather than treating empirically based on appearance alone.
ONYCHOMYCOSIS TYPICALLY PRESENTS WITH:
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Yellow, brown, or white discoloration
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Thickened, crumbly, or brittle nail plate
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Nail separation from the nail bed (onycholysis)
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Debris under the nail
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Odor in some cases
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Often affects multiple nails or spreads over time
NAIL DYSTROPHY DIFFERENCES:
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Frequently affects only the nail(s) subject to trauma
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History of repetitive shoe contact, running, or nail injury
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Does not respond to antifungal treatment
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May have associated skin changes of psoriasis
Visual inspection by a trained professional can help distinguish the two, but often visual inspection alone cannot completely distinguish the two.
ONYCHOMYCOSIS RISK FACTORS:
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Adults over 60 — prevalence increases significantly with age
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Patients with diabetes or peripheral vascular disease
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Immunocompromised patients
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Athletes — particularly swimmers and those in communal facilities
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Those who have had athlete's foot — can spread to nails
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Patients with nail trauma — entry point for infection
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Those who wear occlusive footwear (steel-toed boots and combat boots in our San Antonio community) for long periods
Treatment for Fungal Toenails
Treatment for confirmed onychomycosis depends on the severity of involvement, the number of nails affected, and the patient's overall health and medication profile. Dr. Gunter discusses the most appropriate option after confirming the diagnosis.
Oral antifungal therapy
Systemic oral antifungal medication — most commonly terbinafine — is the most effective treatment for moderate to severe onychomycosis, achieving cure rates significantly higher than topical treatment alone. It requires a course of several months and periodic monitoring depending on the medication and patient health profile. Years of several clinical studies show that it remains very safe for use in patients without existing liver conditions. Dr. Gunter reviews your health history and current medications before prescribing oral antifungals.
Topical antifungal therapy
Prescription-strength topical antifungal agents — including ciclopirox and efinaconazole — penetrate the nail plate to treat the underlying infection. Most effective for mild to moderate involvement or when oral therapy is not appropriate due to health or medication considerations. Requires consistent daily application over many months. Response is slower than oral therapy.
Nail debridement
Regular professional debridement — thinning and reducing the thickness of the infected nail — improves the penetration of topical antifungals and provides cosmetic improvement during the treatment course. For patients who are not candidates for antifungal medication, debridement provides symptomatic management. Particularly important for diabetic patients where thick nails increase pressure-related risk.
Nail avulsion
For severely infected, painful, or non-responsive nails, partial or complete nail removal under local anesthesia allows direct treatment of the nail bed and provides relief from the thickened nail's pressure on the toe. Dr. Gunter discusses nail avulsion when it is the most appropriate option for the specific presentation.
A note on laser nail treatment:
Dr. Gunter does not offer laser treatment for fungal nails at this time. The published clinical evidence supporting laser nail treatment remains weak and inconsistent to date— available studies are limited by small sample sizes, variable methodology, and lack of long-term follow-up. While laser is widely marketed as a nail fungus treatment, it has not demonstrated the reliable efficacy of oral or topical antifungal therapy in well-controlled studies. Dr. Gunter recommends only treatments supported by meaningful clinical evidence, and provides that explanation transparently rather than offering laser as a premium-priced service with uncertain outcomes. Should laser technology improve or more encouraging clinical research emerge at a later date, he remains open to offering any service to his patients when he feels it is in their best interest.
Related conditions: Athlete's foot · Ingrown toenails · Diabetic foot care
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Frequently Asked Questions — Fungal Toenails
Discolored or thickened toenails?
Get the right diagnosis first.
Dr. Andrew Gunter, DPM evaluates nail changes thoroughly — distinguishing true fungal infection from nail dystrophy before recommending treatment. Evidence-based management, accurate diagnosis, and honest recommendations. Serving San Antonio and surrounding communities. Same-day appointments available. Most insurance plans accepted.
Call (210) 581-9800