Whispers of “blue waffle disease” began around 2010. That was when a disturbing image of blue-tinted, pus-covered, lesion-filled labia, said to be the result of a sexually transmitted disease (STD), started circulating online.

While that’s definitely labia in the picture, blue waffle disease isn’t real. But the picture remains a pervasive — and fake — meme to this day.

Almost as unsettling as the photo were the claims that went along with it. Blue waffle disease was said to be an STD that affects only the vagina. Another widespread claim was that this fictional STD only occurred in females with many sex partners.

The name came from the slang terms “waffle,” for vagina, and “blue waffle,” for a serious vaginal infection. Blue waffle disease was rumored to cause lesions, bruising, and blue discoloration.

As it turns out, there is no such disease known in the medical world by that name or with those symptoms — at least not the “blue” part. There are, however, several STDs that can cause discharge and lesions in sexually active people.

Blue waffle disease may not exist, but many other STDs do. If you’re sexually active, it’s important to check your genitals regularly for signs of an STD.

Here are the signs and symptoms of the most common STDs.

BV is the most common vaginal infection in women ages 15–44, according to the Centers for Disease Control and Prevention (CDC). It occurs when there is an imbalance of bacteria normally found in the vagina.

It’s not entirely clear why some people get it, but certain activities that can alter vaginal pH balance increase your risk. These include having a new or multiple sex partners, and douching.

BV doesn’t always cause symptoms. If it does, you may notice:

  • thin vaginal discharge that is white or grayish
  • a fishy odor that becomes worse after sex
  • vaginal pain, itching, or burning
  • burning when urinating

Chlamydia is common and can affect all sexes. It’s spread by having vaginal, anal, or oral sex.

Left untreated, chlamydia can cause serious complications and affect female fertility. It can be cured, but successful treatment requires that you and your partner are treated.

Many people who have chlamydia have no symptoms. If you do develop symptoms, they can take several weeks to appear.

Vaginal symptoms may include:

  • abnormal vaginal discharge
  • burning when urinating

Symptoms affecting the penis or testicles can include:

  • discharge from the penis
  • burning sensation when urinating
  • pain and swelling in one or both testicles

If you have anal sex or chlamydia spreads to the rectum from another area, such as the vagina, you may notice:

  • rectal pain
  • discharge from the rectum
  • rectal bleeding

All sexually active people can contract this STD. Gonorrhea can affect the genitals, rectum, and the throat, and is transmitted by having vaginal, anal, or oral sex with someone who has it.

Gonorrhea may not cause any symptoms. What symptoms that can occur depend on your sex and the location of your infection.

A person with a penis may notice:

  • burning when urinating
  • yellow, white, or green discharge from the penis
  • pain and swelling in the testicles

A person with a vagina may notice:

  • pain or burning when urinating
  • increased vaginal discharge
  • bleeding between periods
  • pain during sex
  • lower abdominal pain

Rectal infections may cause:

  • discharge from the rectum
  • pain
  • anal itching
  • rectal bleeding
  • painful bowel movements

Genital herpes can be caused by two types of the herpes simplex virus (HSV): HSV-1 and HSV-2. It’s primarily spread through sexual contact.

Once you’ve contracted the virus, it lies dormant in your body and can reactivate at any time. There is no cure for genital herpes.

If you have any symptoms, they usually begin within 2 to 12 days after exposure to the virus. Approximately 90 out of 100 people infected will have very mild or no symptoms.

Symptoms may include:

  • pain
  • itching
  • small red bumps
  • tiny white blisters
  • ulcers
  • scabs
  • flu-like symptoms, such as fever and body aches
  • swollen lymph nodes in the groin

HPV is the most common STD. According to the National Cancer Institute, there are more than 200 types of HPV, 40 of which are spread through sexual contact. Most sexually active people will have some type of it during their lifetime. It’s passed through skin-to-skin contact and can affect your genitals, rectum, mouth, and throat.

Some strains can cause genital warts. Others can cause certain cancers, including cancers of the cervix, rectum, mouth, and throat. The strains that cause warts aren’t the same as those that cause cancer.

Most infections go away on their own without causing any signs or symptoms, but the virus remains dormant in your body and can be spread to your sexual partners.

Genital warts caused by HPV can appear as a small bump or a cluster of bumps in the genital area. They can range in size, be flat or raised, or have the appearance of a cauliflower.

Genital warts caused by HPV aren’t the same as genital herpes.

If you notice any unusual changes, such as discharge, bumps, or sores, see your doctor for STD testing as soon as possible.