Overview
Toenails are most affected.
Symptoms
Common signs:
- Thick, yellow nails
- Thick, yellow, or crumbly nails
Less common
- Crumbly nails
When to get medical care
Call 911This isn't an emergency by itself. Call 911 for trouble breathing, chest pain, or fainting.
Get care todayRed, painful skin around the nail.
See a doctor soonBothersome nails.
Causes
Fungus.
Does it spread or run in families?
- The illness itself usually isn't passed to others, but some germs that cause it can spread.
- Washing hands often helps.
Who is more likely to get it
- Older age
- Diabetes
Diagnosis
A clinician may test the nail.
Tests
Tests, if needed:
- Nail test:
Treatment
Treat and protect.
Self-care
- Keep feet dry
- Wear sandals in showers
- Trim nails straight
Medicines
Medicines that may help:
| Medicine | Helps with | Good to know |
|---|---|---|
| Pills | Fungus | Prescription. |
| Nail lacquer | Mild |
OwieClear doesn't give doses: follow the label or your healthcare professional. Medicine names here are examples, not a full list.
Prevention
To lower your risk or prevent problems:
- Keep feet dry
- Wear sandals in locker rooms
Which doctor treats this
- Start with your primary care provider (family doctor or internist).
- They may send you to a dermatologist (skin doctor).
Back to school, work, or sports
- Most people keep up normal school and work. Rest when you need to.
Children, pregnancy, and older adults
- Older adults: More common.
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your prenatal provider about this condition.
- Some skin medicines, like isotretinoin and retinoid creams, aren't safe in pregnancy.
- Some infections can pass to the baby during pregnancy or birth. Tell your provider if you've been exposed.
- Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
- Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
- Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.
Outlook
Slow to clear.
Getting ready for your visit
Bring a list of your symptoms and medicines.
Questions to ask
- Which treatment works best?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Sources
Last updated 2026-11-12.