Nails are more than just cosmetic features—they protect your fingertips and reflect your overall health. But when nails become discolored, thickened, or crumbly, it may not just be a cosmetic concern. One of the most common culprits? Onychomycosis, or fungal nail infection.
This condition affects millions of people worldwide, yet it often goes untreated until it becomes severe or painful. In this blog, we’ll explore everything you need to know about onychomycosis—what it is, why it happens, how to treat it, and how to prevent it from coming back.
What is Onychomycosis?
Onychomycosis (pronounced on-ee-ko-my-KOH-sis) is a fungal infection of the nails, most commonly affecting the toenails, though fingernails can also be involved. It typically develops slowly and causes nails to become discolored, thickened, brittle, and sometimes painful.
Medical Terminology
The term “onychomycosis” is derived from:
- Onycho- (Greek for “nail”)
- Mycosis (meaning fungal infection)
There are several subtypes, depending on the area of the nail involved and the pathogen:
- Distal lateral subungual onychomycosis (DLSO) – the most common form
- White superficial onychomycosis (WSO)
- Proximal subungual onychomycosis (PSO)
- Candidal onychomycosis
How Common is It?
Onychomycosis is extremely common. Studies estimate that:
- 10% of the general population has a fungal nail infection.
- The incidence increases with age—up to 50% of people over 70 may be affected.
- Men are more likely to be affected than women.
- It is more common in people with weakened immune systems, diabetes, circulatory issues, and athlete’s foot.
What Causes Onychomycosis?
Onychomycosis is primarily caused by fungi known as dermatophytes, but yeasts and non-dermatophyte molds can also be responsible.
1. Dermatophytes
The most common cause of onychomycosis. These fungi feed on keratin (a protein in nails) and thrive in warm, moist environments. The most frequent culprit is Trichophyton rubrum.
2. Yeasts (e.g., Candida)
More common in fingernail infections, particularly in people who frequently immerse their hands in water.
3. Non-Dermatophyte Molds
Can cause infections, especially in warm climates or following trauma to the nail.
Risk Factors
You may be more likely to develop onychomycosis if you:
- Wear tight or non-breathable shoes
- Frequently use public swimming pools, gyms, or showers
- Have sweaty feet
- Suffer from athlete’s foot (tinea pedis)
- Have diabetes, circulatory problems, or immune suppression
- Are elderly (slower nail growth and reduced immunity)
- Have nail trauma or psoriasis
- Have poor foot hygiene or wear artificial nails long-term
Signs and Symptoms
Onychomycosis often starts subtly but becomes more noticeable over time. The typical symptoms include:
✅ Discoloration
- Yellow, white, or brown spots
- Entire nail may turn dark over time
✅ Thickened Nails
- One of the hallmark signs of fungal infection
- Makes trimming difficult
✅ Brittle or Crumbly Texture
- The nail may split or crumble at the edges
✅ Distorted Nail Shape
- Irregular growth or lifting from the nail bed (onycholysis)
✅ Foul Odor
- In some cases, infected nails may emit a slightly unpleasant smell
✅ Pain or Discomfort
- Especially when pressure is applied (e.g., walking, wearing shoes)
Complications of Onychomycosis
While it may seem like a cosmetic issue, onychomycosis can lead to:
- Painful walking or standing
- Spread to other nails or the skin (especially athlete’s foot)
- Secondary bacterial infections
- Permanent nail damage or loss
- Increased risk of foot ulcers in diabetics
- Emotional and social distress due to nail appearance
How Is It Diagnosed?
A visual inspection by a doctor is often enough for suspicion, but laboratory tests are needed to confirm a fungal infection.
Diagnostic Tools:
1. Nail Clipping and Microscopy
A sample is taken from the affected nail, treated with potassium hydroxide (KOH), and examined under a microscope to look for fungal elements.
2. Fungal Culture
Samples are grown in a lab to identify the exact species. This helps guide treatment.
3. PCR Testing
Polymerase chain reaction (PCR) tests can quickly identify fungal DNA. More accurate but not always available.
4. Histology
A small nail biopsy is examined under a microscope for fungal invasion.
Treatment Options for Onychomycosis
Treating onychomycosis can be challenging and slow, due to the nail’s slow growth and the protective barrier the nail provides for the fungi. Treatment may last months and often requires combined approaches.
1. Topical Antifungals
Over-the-Counter:
- Clotrimazole
- Tolnaftate
Prescription:
- Efinaconazole (Jublia)
- Tavaborole (Kerydin)
- Ciclopirox (Penlac)
Pros: Fewer side effects
Cons: Less effective for severe or extensive infections
✅ Best for: Mild to moderate infections or patients who cannot tolerate oral medications.
2. Oral Antifungals
- Terbinafine (Lamisil) – most effective and commonly prescribed
- Itraconazole (Sporanox)
- Fluconazole (Diflucan)
Pros: Higher cure rates
Cons: Risk of liver toxicity, drug interactions, and need for blood monitoring
✅ Best for: Moderate to severe infections or when multiple nails are affected.
3. Laser Therapy
A newer treatment where laser energy targets the fungus without damaging the surrounding tissue.
Pros: Painless, minimal downtime
Cons: Expensive, not always covered by insurance, and mixed success rates
✅ Best for: Patients looking for non-pharmacologic options
4. Nail Removal
In some cases, the entire nail may need to be removed surgically or chemically if it is severely damaged or painful.
Temporary removal allows topical treatments to work more effectively.
Permanent removal is rarely needed unless infections are chronic and untreatable.
5. Home Remedies and Natural Treatments
Some people turn to natural solutions like:
- Tea tree oil
- Vicks VapoRub
- Apple cider vinegar soaks
- Listerine foot baths
- Coconut oil
While some of these may help mild infections or prevent recurrence, scientific evidence is limited. These should not replace medical treatment for moderate or severe cases.
Treatment Duration and Expectations
- Fingernail infections: 4–6 months
- Toenail infections: 6–12 months
- Nail must grow out completely free of infection, which takes time.
It’s important to complete the full course of treatment even if symptoms improve early. Recurrence is common if fungi are not fully eradicated.
Preventing Onychomycosis
Preventing fungal nail infections requires attention to hygiene, footwear, and environmental exposure.
✅ Good Nail Hygiene
- Keep nails short, clean, and dry
- Use clean, sanitized nail clippers
- Avoid biting nails or cutting cuticles too aggressively
✅ Foot Protection
- Wear shower shoes in public places
- Change socks daily
- Choose breathable, moisture-wicking footwear
- Rotate shoes to let them dry between wears
✅ Manage Underlying Conditions
- Control blood sugar if diabetic
- Treat athlete’s foot promptly
- Avoid trauma to the nails
✅ Disinfect Nail Tools
If you visit salons, ensure they properly sterilize tools—or bring your own.
✅ Antifungal Sprays and Powders
Use inside shoes or on feet if you’re prone to sweating or recurrent infections.
When to See a Doctor
You should consult a doctor if:
- The nail is thickened, discolored, or separating from the nail bed
- There is pain, swelling, or foul odor
- You have diabetes or a weakened immune system
- Home remedies or OTC treatments haven’t worked
- Multiple nails are affected or symptoms are spreading
Early diagnosis and treatment are key to preventing complications and improving success rates