Something stinks. It's not your pits. It's, um, a bit further down. Think: Your bellybutton. And yes, it's entirely possible that that's the cause of your strange stench.
This probably won't be the case if you have an outie bellybutton, but if you have an innie, then odor can totally happen.
"The physical structure of an 'innie' bellybutton puts it at risk for a variety of infections," says Joshua Zeichner, MD, the director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City. "It creates a moist environment that allows for the overgrowth of bacteria and fungi."
In a study examining the "habitat" of 60 bellybuttons, researchers identified nearly 2,400 species of bacteria within them, according to a November 2012 PLOS One paper. One of the most common was staphylococci, which isn't that surprising, considering one-third of people naturally carry this on their skin anyway, notes the Centers for Disease Control and Prevention (CDC). Most of the time, the bacteria and yeast that naturally populate your skin don't cause a problem — but under the right conditions, they can.
People with larger body sizes may notice bellybutton issues more often "because it creates a larger area that can trap the overgrowth of microorganisms," Dr. Zeichner says.
He adds that people with diabetes are also more likely to develop these problems because the disease compromises both skin and the immune system. Still, that does not mean you're particularly dirty or lack good hygiene — only that you may be more likely to run into this problem, and it's something to have on your radar.
When people complain of bellybutton smells, they use all kinds of adjectives to describe them: Cheesy, sour or even "like poop."
Here's what may be happening: Overgrowth of yeast on the skin can lead to a condition called intertrigo, Dr. Zeichner says. This type of rash routinely shows up in the folds of skin, and you'll notice that it's red, inflamed and even cracked or peeling, per DermNet NZ.
"In some cases, there may be a foul smell," Dr. Zeichner says. A topical OTC antifungal cream (like those used to treat athlete's foot) will clear it right up. If not, your dermatologist can prescribe a stronger ointment.
If a smelly bellybutton is a common problem for you, ask your dermatologist or doctor if there are any additional skin-care steps you should add to your routine. Otherwise, "be extra careful with your hygiene and making sure that your bellybutton is washed with soap and water, just as you would wash other parts of the body," Dr. Zeichner says, adding that we often forget to soap up this area. (So, no, you can't just assume that the soapy water running down your body will clean these sometimes-hidden areas.)
Side note: You may notice your bellybutton clogs up with lint on the regular. That's because hair circling your bellybutton takes up fibers from your shirts and funnels them down into your innie where they collect, along with skin cells, into "lint," researchers explain in a June 2009 paper in Medical Hypotheses. One fix is to shave the hair in this area, but wearing older shirts also keeps you mostly fuzz-free. The catch is, researchers say, that lint might actually help keep the bellybutton clean. So, maybe embrace "bellybutton lint picking" as a hygiene hobby?
When to See a Doctor
If your rash isn’t going away, it’s looking crusty or has scabs, or if it’s painful or — yep — even smelly, talk to your dermatologist or doctor, Dr. Zeichner says.