A toenail that turns yellow, thick, brittle, or crumbly looks like an obvious case of fungus. Sometimes it is. Sometimes it is not.

Nail psoriasis, repeated trauma from shoes, age-related changes, and other nail disorders can resemble a fungal infection. Treating the wrong problem with months of antifungal medication can waste time and leave the nail unchanged.

Thomas Dermatology provides nail fungus evaluation and treatment at its dermatology locations in Las Vegas, Henderson, and Northwestern Arizona. The first step is confirming what is actually affecting the nail.

What Does Nail Fungus Look Like?

Nail fungus, also called onychomycosis, can affect fingernails or toenails, although toenails are more commonly involved.

Possible signs include:

• Yellow, white, or brown discoloration
• Thickening
• Brittleness or crumbling
• Debris beneath the nail
• Distortion of the nail shape
• Separation from the nail bed
• More than one nail gradually becoming involved
• Odor in some cases

The American Academy of Dermatology’s nail fungus guidance notes that other conditions can look similar, including nail psoriasis and injury. That is one reason an examination matters before assuming every thick nail is fungal.

Why Toenail Fungus Is So Common

Fungi thrive in warm, moist environments. Feet spend long periods inside shoes, and small nail or skin injuries can make it easier for organisms to enter.

Risk can be higher in people who have:

• A history of athlete’s foot
• Repeated exposure to communal showers, locker rooms, or pools
• Heavy sweating
• Nail injuries
• Diabetes
• Circulation problems
• A weakened immune system
• Psoriasis
• Older age

Having a risk factor does not mean a nail change is definitely fungal. It simply changes the likelihood and may affect how a dermatologist approaches testing and treatment.

Why a Dermatologist May Test the Nail First

Visual inspection can strongly suggest fungus, but it cannot always confirm it.

A dermatologist may collect a clipping, scraping, or small amount of material beneath the nail for laboratory evaluation. According to the AAD, testing can help distinguish fungal infection from nail psoriasis or trauma and may help guide treatment.

This becomes especially useful when:

• Only one nail is affected
• The appearance is unusual
• Previous antifungal treatment failed
• An oral medication is being considered
• The patient also has psoriasis
• The nail has been repeatedly injured
• Several possible diagnoses fit the appearance

Thomas Dermatology’s general dermatology services include both nail fungus and psoriasis, which allows the clinical team to consider conditions that can overlap in appearance.

When Over-the-Counter Products May Not Be Enough

Drugstore treatments are appealing because they are easy to start, but nail fungus can be difficult to treat. The infection may involve areas beneath or within the nail that topical products do not reach effectively.

The right treatment depends on how much of the nail is involved, which nails are affected, the organism, other medical conditions, current medications, pregnancy status, and the risks and benefits of each option.

A dermatologist may discuss topical prescription therapy, oral antifungal medication, nail thinning or debridement, or other approaches based on the individual case.

Do not borrow someone else’s prescription or keep layering products onto a nail that has never been properly diagnosed.

Why Treatment Takes Time

Even after an infection is controlled, the damaged part of a nail does not instantly disappear.

Toenails grow slowly. Improvement becomes visible as healthier nail gradually grows from the base and the damaged portion moves outward. That means a successful treatment can still require patience before the nail looks normal again.

The AAD emphasizes that nail regrowth is slow and treatment takes time. A dermatologist can explain what changes should be expected and when the nail should be reassessed.

Oral Antifungal Medication Is Not for Everyone

Oral antifungal medication may be appropriate for some patients with more extensive or persistent nail fungus, but it is a prescription treatment that requires medical review.

A clinician considers current medications, liver health, pregnancy or breastfeeding, other medical conditions, and possible drug interactions. Depending on the medication and patient, laboratory testing may be recommended.

Never stop another prescribed medication or begin an oral antifungal based solely on internet advice. The decision should be individualized.

Nail Fungus Versus Nail Psoriasis

Nail psoriasis can cause pitting, thickening, discoloration, crumbling, and separation from the nail bed. Those changes can look fungal, and the two conditions can sometimes occur together.

Thomas Dermatology provides psoriasis diagnosis and treatment for skin and nail involvement. If psoriasis is suspected, the treatment plan can be very different from a plan for isolated fungal infection.

This is a good example of why a nail that “looks like fungus” is not always enough information to choose the treatment.

Can Nail Fungus Spread?

Fungal organisms can spread from one nail to another and may coexist with athlete’s foot on the surrounding skin. Shared environments and contaminated tools can also contribute to transmission.

Practical habits that can reduce exposure include:

• Wearing footwear in communal showers and locker rooms
• Keeping feet clean and dry
• Changing damp socks
• Allowing shoes to dry between uses
• Keeping nails trimmed appropriately
• Avoiding shared nail tools
• Choosing reputable nail salons with appropriate sanitation practices
• Treating athlete’s foot when it occurs

If you have diabetes, poor circulation, numbness in the feet, or a weakened immune system, ask your healthcare provider how to handle foot and nail problems safely rather than trying to cut away thick or painful areas yourself.

When a Nail Change Needs a Dermatology Visit

Consider scheduling an appointment when:

• The nail change persists for months
• Several nails are involved
• A nail becomes painful
• The nail is lifting or deforming
• The skin around the nail becomes inflamed
• Home treatment has not helped
• You have diabetes or circulation problems
• You are unsure whether the problem is fungal
• You also have psoriasis or another chronic skin condition
• You are considering oral antifungal medication

A changing dark streak or pigment beneath a nail also deserves prompt medical evaluation because not every discoloration is fungal.

What to Expect at the Appointment

A dermatology visit typically includes a review of how the nail changed, current medications, medical conditions, prior treatment, and possible exposures.

The provider may examine other nails and the surrounding skin, particularly for athlete’s foot or psoriasis. If testing is appropriate, a clipping or scraping can be collected.

From there, the treatment plan can be based on the diagnosis rather than guesswork.

Nail Fungus Care at Thomas Dermatology

Thomas Dermatology has provided medical, surgical, and cosmetic dermatology care for more than three decades. Patients can receive general dermatology care in Las Vegas, Henderson, and the practice’s Arizona locations.

Visit the Thomas Dermatology locations page to find the most convenient office, or review the practice’s broader general dermatology services.

Frequently Asked Questions About Nail Fungus

Will nail fungus go away on its own?

Some mild cases may remain limited, but fungal nail infections often persist without effective treatment. A dermatologist can confirm whether fungus is present and discuss whether treatment is appropriate.

Is every yellow toenail fungal?

No. Trauma, psoriasis, aging, staining, and other nail disorders can change color or thickness. Testing may be useful when the diagnosis is uncertain.

How long does treatment take?

The infection may respond before the nail looks normal. Toenails grow slowly, so the visible recovery can take many months as healthier nail grows out.

Can I get nail fungus from a pedicure?

Fungal organisms can spread through contaminated tools or surfaces. Choose salons that follow appropriate cleaning and sterilization practices and avoid procedures on broken or infected skin.

Should I see a dermatologist if only one nail is affected?

Yes if the change is persistent, painful, unusual, or unexplained. A single abnormal nail may have several possible causes.

Get the Diagnosis Before Committing to Months of Treatment

Nail fungus is common, but appearance alone is not always enough to identify it correctly.

A dermatology evaluation can confirm the diagnosis, rule out look-alike conditions, and create a treatment plan that accounts for your overall health and medications.

Schedule an appointment with Thomas Dermatology for a persistent or changing nail concern.

*This article is for general educational purposes and does not replace an individual medical evaluation. Seek prompt medical care for severe pain, rapidly spreading redness, drainage, fever, or another concerning change around a nail.*