You can get urethritis if bacteria infect your urethra — the tube that transports urine (and in men, semen) out of the body — and causes it to become inflamed. It’s most commonly caused by having sex with someone harboring a sexually transmitted infection (STI), whether they realize it or not. Urethritis is a type of lower urinary tract infection that can affect both men and women.
Causes of Urethritis
The most common causes of urethritis include:
- Having sex with a partner who has an STI.
- Injury to the urethra, such as from a urinary catheter.
- A chemical reaction from spermicides, soaps, antiseptics, or other irritants.
- Genital irritation due to tight clothing, sex, or activities such as riding a bike.
- A symptom of reactive arthritis.
- In older women, a lack of estrogen.
In some cases, the infection’s cause is unknown.
The Bacteria Involved
The bacteria that can cause urethritis are some of the same ones that cause STIs, including:
- Neisseria gonorrhoeae, which causes gonorrhea and is spread through vaginal, oral, and anal sex.
- Chlamydia trachomatis, which causes chlamydia and also spreads through vaginal, oral, and anal sex.
- Escherichia coli, typically spread through stool.
- Mycoplasma genitalium, a sexually transmitted bacterium.
- Ureaplasma urealyticum, another sexually transmitted bacterium.
The first two bacteria on this list are the most common causes of urethritis.
Certain viruses, parasites, and fungi can also cause urethritis. These are rare, however, and most infections are caused by bacteria.