The ear canal has glands that produce a waxy oil called cerumen. This often emerges from the opening of the ear and is commonly known as earwax.
It may fall out naturally or be washed away.
Earwax serves to protect your ear by trapping and preventing dust, bacteria, and germs from entering and damaging it. It also protects the ear canal’s skin from irritation when water gets inside.
“Normal earwax is a natural mixture of oils, dead skin cells, and sweat that typically has a faint or neutral smell,” says Geoffrey B. Trenkle, DO, an otolaryngologist and the founder of the Los Angeles Center for Ear, Nose, Throat, and Allergy. “A foul odor usually signals a disruption in this natural mixture by either biochemical or environmental factors.”
Here are some of the causes of foul-smelling earwax.
Excessive Earwax
A surplus of earwax can cause a bad smell because it creates a prime environment for microbial overgrowth, Dr. Trenkle says.
“A large plug of wax can completely block the ear canal, creating an airtight, oxygen-deprived space,” Trenkle says. Trapped material like dust, moisture, sweat, or drainage, combined with skin cells, becomes the perfect place for bacteria or fungus to colonize — certain bacteria, particularly those associated with foul odors, thrive in these environments with no oxygen, he adds.
Untreated earwax buildup can lead to a blockage in your ear. You’re more likely to develop this if you use hearing aids, earplugs, or earbuds. Other risk factors include more ear hair, skin conditions such as eczema, using cotton swabs, or being older than 55.
Excessive earwax typically has a faint odor that is sometimes musky, Trenkle says.
Swimmer’s Ear
The scientific name for swimmer’s ear is otitis externa, or inflammation of the external ear canal. This inflammation can either be infectious or non-infectious.
“Swimmer’s ear is often caused by Pseudomonas or Staph bacteria, both of which commonly create foul-smelling discharge,” says Ravi Patel, MD, an otolaryngologist with ENT and Allergy Associates in New York City.
Swimming is among the main risk factors, with swimmers five times more likely than non-swimmers to develop it. Others include humidity, cotton swabs or external tools like earplugs, narrow external ear canals, stress, or a compromised immune system.
Swimmer’s ear, along with cholesteatoma and other infections (more on both of those ahead), typically has a strong scent that’s rotten, sour, or even cheesy, Trenkle says.
Cholesteatoma
Cholesteatoma is a skin cyst found in the middle ear. Although some people are born with it, it usually occurs due to a chronic ear infection. These cysts are filled with old skin cells and other waste. Symptoms include dizziness, ear drainage, hearing loss in one ear, or a feeling of fullness or pressure in the ear.
Surgery is necessary to remove this cyst. Otherwise, it may become infected or continue to grow.
“The cyst continuously sheds dead skin cells into a confined, unventilated space, causing a very strong and distinct cheesy odor,” Trenkle says.
Ear Infection
A foul odor accompanied by symptoms like ear pain or trouble hearing is a strong indicator of an infection. Sometimes, if a middle ear infection causes eardrum perforation, drainage may also occur alongside pain and hearing issues.
In an ear infection, the eustachian tubes that run from the middle ear to the throat become blocked and swollen, leading to mucus that can become infected. Bacteria or a virus in the middle ear — usually coming from another illness like a cold, flu, or allergy — cause ear infections.
Although children are more likely to get ear infections because of the size and shape of their eustachian tubes (which run from the middle ear to the throat), adults can experience them as well.
As mentioned, Trenkle says infections usually have a strong rotten, sour, or cheesy odor.
