Expert Answers Factual Answers to Your Sexual Health Questions

Anonymous on August 8, 2011

Can you catch trichomoniasis from anal sex?

My boyfriend and I have been faithful to each other, but now we’ve both been diagnosed with trich. Could this be because we recently tried anal sex?

answered by
Lisa Oldson, MD on August 8, 2011

Thanks for your question. I hope I can help clear up the confusion that you and your boyfriend might be feeling, but I do encourage you to ask your doctor any questions you have about your diagnosis. Recommendations change based on the person and the situation.

In general, it’s unlikely to catch trichomoniasis from anal sex. Trichomoniasis (sometimes called “trich” for short) is a small parasite that usually infects the vagina in women and the urethra in men. The Centers for Disease Control and Prevention say that most people catch trich from penis-to-vagina intercourse or vulva-to-vulva contact with someone who has trichomoniasis. Because the parasite that causes trichomoniasis doesn’t live in the anus or rectum, it’s unlikely to became infected through anal sex.

Finding out you have trichomoniasis doesn’t mean that you or your partner has been unfaithful. The parasite the causes trichomoniasis can live in a “carrier” (potentially you or your boyfriend) for a long time without showing any symptoms. In fact, a lot of men never have symptoms even if they’re infected. Women are more likely to have symptoms when the parasite becomes active...they usually experience a yellowish-green discharge that doesn’t smell good.

It’s very important for couples to get treated for trichomoniasis together to avoid re-infecting each other. It’s also a good idea to wait one week after both people have completed treatment before having sex again. Using condoms or dental dams when sex is resumed can also help reduce the risk of trich re-infection and the risk of spreading other STDs. Follow your doctor’s instructions after taking the medication...some medications used to treat trichomoniasis can make you sick if you drink anything alcoholic within 24 hours.

In addition to getting tested and treated for trichomoniasis, talk to your doctor about getting tested for other STDs. It turns out that a lot of people with trichomoniasis also have chlamydia or gonorrhea. And studies show that being infected with trichomoniasis also increases the likelihood that women will contract HIV if they happen to be exposed to the virus.

All of these diseases, if left undiagnosed and untreated, can cause serious health problems down the road. Testing is the only way to know for sure whether you have any other STDs...and it’s better to know about them early, and get treated if necessary. For example, chlamydia and gonorrhea can be easily cured with a single dose of antibiotics. And HIV treatment is improving every day...most people who start highly active antiretroviral therapy (HAART) in the early stages of HIV infection live a normal quality of life. You can find out more about these and other STDs in our Expert Guides.

One more thing...what are the risks of anal sex? Be aware that there are some bacteria that live in the anus, that shouldn’t live in the vagina. So when you have anal sex, use condoms...and make sure that anything that goes in the anal cavity (for example, your boyfriend’s penis or a sex toy) doesn’t come into contact with the vagina until you change the condom and/or wash thoroughly.

I hope this information helps you understand your diagnosis of trichomoniasis a little better. You can also learn more about trichomoniasis risk factors, symptoms and treatment in our Trichomoniasis Overview. I wish you both the best of health!

Related info:

Lisa Oldson, MD

Dr. Oldson is Medical Director of the Analyte Physicians Group. She is on staff at Northwestern Memorial Hospital, as well as Clinical Instructor at the Feinberg School of Medicine, Northwestern University. Her areas of expertise include STDs (with a particular clinical emphasis on herpes), women's health, preventive medicine, diabetes, obesity and weight management, and mood and anxiety disorders. Dr. Oldson was educated at Rush Medical College and completed her residency at Rush-Presbyterian-St. Luke's Medical Center in Chicago, IL.

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