Beyond Ugly Toenails: Diagnose Onychomycosis with Confidence

Welcome back, DERM Community!

Last week, we explored Molluscum contagiosum, the viral imposter that masquerades as acne, bites, or warts.

Did you catch the pearl-like lesions and viral clues? If not, find it in our archive.

This week on Beneath the Surface, we’re heading distal to the tips of toes and fingers.

Let’s talk onychomycosis, the chronic fungal infection that quietly erodes nails and patient confidence alike.

You’ve seen it: thickened, yellow, brittle nails that resist trimming and treatment.

Sometimes it’s just cosmetic.
Sometimes it signals deeper health concerns.
Always, it’s worth a second look.

Featured on This Week’s Chapter:

Learning Opportunities: Onychomycosis 101

It starts subtle. A slight discoloration. A crumbly edge.

Then it spreads. Thickens. Distorts.

Sound familiar?

Onychomycosis affects up to 10% of the population and yet, it’s underdiagnosed, overtreated, or just plain ignored.

This week, we’re breaking down:

1. The types of onychomycosis (and how to tell them apart)
   

2. When topicals won’t cut it
   

3. The truth about labs, lasers, and Lamisil
   

4. How to talk to patients who think it’s “just ugly toenails”

What is Onychomycosis?

It is a fungal infection of the nail unit (nail plate, bed, and matrix) primarily caused by dermatophytes (especially Trichophyton rubrum), but also yeasts and non-dermatophyte molds.

It is chronic, slowly progressive, and contagious, affecting toenails more commonly than fingernails.

Pathogenesis (What’s Really Happening?)

Infection begins when fungi breach the stratum corneum or nail plate, usually via microtrauma, onycholysis, or pre-existing nail disease.

Dermatophytes produce enzymes like keratinases that allow them to digest nail tissue and penetrate deeper into the nail bed and matrix.

Over time, the immune response triggers hyperkeratosis, acanthosis, and inflammation, leading to thickened, discolored, and brittle nails.

Without treatment, onychomycosis can progress to total dystrophic nail destruction.

Need more than just an infographic?

 We Made You a Free, Downloadable Guide:

Want to see real cases with real outcomes?

Whether you’re a clinician, student, or educator, our hair and nail health module walks you through the essentials, covering everything from androgenic alopecia, alopecia areata, and trichotillomania to nail disorders like onychomycosis, paronychia, ingrown toenails, and subungual hematomas.

Clear explanations, clinical visuals, and real examples make it easier to recognize, diagnose, and manage these conditions with confidence.

Get the tools to manage nails that crumble, lift, or confuse with clarity.

Looking for a job?

Whether you're actively seeking your next big move or simply curious about what’s out there, now’s the time to explore fresh possibilities in dermatology.

We’ve curated the latest job openings: from academic appointments and private practices to telederm roles and research positions.

Why browse now?

• Discover opportunities aligned with your passion
  

• Find roles with flexible schedules or leadership potential
  

Explore new locations, new teams, or new modalities (hello, AI-driven diagnostics!)

👋🏻 See you next Thursday, DERM community!

Thanks for joining us on Beneath the Surface.

Onychomycosis may not be dramatic, but it’s persistent, underdiagnosed, and often misunderstood. From cosmetic concerns to deeper systemic red flags, it deserves a thoughtful, evidence-based approach.

The real win? Early recognition, accurate testing, and managing expectations so patients feel seen, and treatment doesn’t feel like guesswork.

If today’s takeaways sharpened your nail game, pass it on to your peers, students, or podiatry friends.

Until next week, friends!

— The Derm for Primary Care Team