4 Reasons Your Fingernails Smell, and What to Do About It

You bring a nail up to your mouth for a little nibble. Sure, you know biting your nails isn't the best habit. But at the moment, you've got a bigger concern: Your fingernails seem to be radiating a strange, not-so-nice smell. What gives?

First, don't panic. Considering how many things our fingernails come into contact with each day, the occasional weird smell isn't all that uncommon (and can usually be managed pretty easily). But in some cases, an unpleasant fingernail odor could be a sign that you're dealing with a problem like nail fungus.

Here's what causes a smell under your fingernails and what you can do about it.

The edges of your nails are like little dirt traps, especially if you haven't clipped them in a while.

"Oftentimes when a fingernail is long, residual smells and materials can get stuck under there and cause an odor," explains Miami-based board-certified dermatologist Anna Chacon, MD. That's especially true if you didn't wash your hands after touching the funky culprit.

In some cases it could be something pungent that you cooked or ate, such as onions or garlic. Spent time working in the garden without gloves? You could be getting a whiff of dirt. And if you went to the bathroom or changed a diaper and forgot to suds up (or didn't suds up well enough), you could even be smelling, well, poop.

Just-snipped nails can sometimes have a pungent odor right after trimming. For that, you can thank stinky sulfur compounds that exist inside the keratin proteins of the nails. Give your nail a trim, and you might smell an odor coming from the freshly cut end, Dr. Chacon says.

Onychomycosis, or nail fungus, can cause toenails or fingernails to have a cheesy or foot-like odor that doesn't ease up even after washing your hands, Dr. Chacon explains. The problem typically causes other nail changes too, according to the Mayo Clinic, including:

• Appearing thick, yellow or whitish
• Being brittle or crumbly
• Having a distorted shape

Certain health problems can cause unusual odors throughout the body, so it's possible to notice the smells on your hands or fingers. Undiagnosed or poorly managed diabetes can trigger a sweet or fruity smell, while liver or kidney disease can potentially cause a bleach-like smell, Dr. Chacon says.

Certain metabolic disorders, like trimethylaminuria, can cause a person to have body odor that smells like rotting fish or garbage, according to the U.S. National Library of Medicine.

These conditions don't typically affect the smell of the fingernails specifically, though. Usually medical problems that cause a strange or unpleasant odor tend to affect the smell of the entire body, not just your fingertips.

A foul smell on your nails probably isn't cause for concern if it goes away quickly and can be traced back to something you touched or did (like trimming your nails).

But if the odor sticks around even after washing your hands and nails thoroughly, persists in other areas of the body or is accompanied by other symptoms (especially redness, swelling and pus drainage), give your doctor a call. You could have nail fungus or another underlying medical condition that needs to be treated, Dr. Chacon says.