STIs: types, testing and treatments

This blog post describes the various main types of STI’s, symptoms, testing and treatment. They are generally categorised as bacterial, viral or parasitic.

Lets start with the most common…

  1. Chlamydia: bacterial. Represents 49% of all new STI diagnoses in the UK in 2018, and is most prevalent in the under 25s age group. Testing at least 2 weeks after unprotected sex.
  • The reason why it is so important to test for chlamydia is that many people are asymptomatic – 70% of women are, and they also account for a higher amount of chlamydia infections (PHE, 2019)
  • Chlamydia testing has gone down by 22%, although infections increase
  • This is an infection you can get in the throat, and eyes, where it can be irritable, swell, cause pain, have discharge (FPA, 2019). It is less frequently passed on through oral sex (NHS, 2018)
  • Symptoms for people with vulvas: bleeding between periods and/or heavier periods (including if you’re on hormonal contraception), after sex; pain and/or bleeding when you have sex; lower tummy pain (from the pelvis); pain from vaginal discharge when weeing
  • Test: a swab (like a massive cotton bud) inserted into the vagina, circling 5-10 times inside (FPA, 2019)
  • Symptoms for people with penises: a white/cloudy/ watery discharge from the penis; pain when weeing; rarer: pain in the testicles (FPA, 2019)
  • Test: urine sample. Throat/anus swab for people with penises having sex with each other
  • Treatment: antibiotics for anywhere between 3-12 days. Repeat test 3 months after
  • Long term: can affect fertility (Brook, 2020)
  1. Gonorrhoea: bacterial. Second most common in the UK, a 26% increase (PHE, 2019) owing to drug-resistant strains (known as XDR-NG). Testing at least 2 weeks after unprotected sex.
  • Commonly transmitted through oral sex (NHS, 2018)
  • Similar to chlamydia, infections can be in other parts of the body. Same tests
  •  Symptoms for people with vulvas: any abnormal vaginal discharge could be thin/watery/yellow/green; painful when peeing; lower tummy pain/feels tender; occasional bleeding between periods or heavier periods (including if you’re on hormonal contraception) (FPA, 2019)
  • Symptoms for people with penises: An unusual discharge from the tip of the penis – the discharge may be white, yellow or green; painful peeing; rarely, pain or tenderness in the testicles
  • Treatment: antibiotic injection, and then a tablet (ibid). It is becoming increasingly treatment-resistant
  • Long term: can affect fertility (Brook, 2020)
  1. Genital warts: viral. Caused by the HPV (human papilloma virus). 
  • Two types of virus (6 and 11) that cause warts, but not cancer (FPA, 2019). HPV (other forms) can cause cervical cancer. 56% decrease due to the introduction of the HPV vaccine as young women were vaccinated before this data was collected
  • Can be spread skin-skin. More likely to be passed on if someone has visible warts. It is less frequently passed on through oral sex (NHS, 2018)
  • Symptoms: see here for the list of where they develop on the body. Can be itchy, inflamed. Some people might bleed from the anus and urethra
  • Most people don’t develop visible warts. Clears from the body over time, but can grow and are infectious
  • If they do, at least 3 weeks to show, but you can get tested immediately. Main test is visual
  • Treatment: cream (specific for genital warts), freezing, heat, surgery, laser (local anaesthetic) (ibid)
  1. Genital herpes: viral. Caused by herpes simplex. Two types: HSV 1 and 2. Accounts for 8% of 2018 STIs (Brook, 2020).
  • Commonly transmitted through oral sex (NHS, 2018); see here for more information on transmission (it’s quite complex)
  • Outbreaks can last 2-4 weeks
  • Virus becomes inactive over time
  • Symptoms: people tend to get a stinging/itching in the genital/anal area, owing to small blisters which burst and leave sores (FPA, 2019)
  • Test: visual, swab, occasionally blood test for antibodies
  • Treatment: antiviral tablets within 5 days of the first outbreak. Can take them again if more outbreaks for 1-3 days. >5 outbreaks/year = longer course of treatment. Tips for soothing treatment and ways to prevent outbreaks found here (useful for everyone to know!)
  • Long term: there is no cure, so you can get more outbreaks. They tend to be less severe, and your body will produce antibodies against it (Brook, 2020; FPA, 2019)
  1. Syphilis:  Bacterial. 7,541 diagnoses of syphilis reported in 2018, a 5% increase since 2017 (PHE, 2019).
  • Commonly transmitted through oral sex (NHS, 2018)
  • Stages: early (primary and secondary syphilis), latent, late (FPA, 2019). The latent has no symptoms. It can appear 2 weeks – 3 months after contact
  • Having syphilis means you can be at a greater risk of contracting HIV
  • Primary symptoms: ulcers anywhere on the body, but tend to be around/on the genitals.they are very infectious, can take 2-6 weeks to heal (ibid)
  • Untreated syphilis develops to a second stage after 4-10 weeks of any ulcers showing (ibid)
  • Secondary: more symptoms. Painless rash, wart-like growths, flu-like illness, patchy hair loss, white patches on tongue/cheeks/roof of mouth (ibid)
  • Latent: no symptoms but a positive blood test. Can pass on
  • Later syphilis has more serious health implications, but is much rarer in the UK (ibid)
  • Testing: if you think you might have it, get tested as soon as possible. Blood test and physical examination to look for bodily symptoms such as ulcers/growths. Swabbing ulcers 
  • Treatment: antibiotics. Often with penicillin. Let your healthcare professional know if you have a penicillin allergy. Primary, secondary, latent syphilis can be cured. Late phase can cause longer-term damage
  1. Trichomoniasis: Parasitic; the parasite is called Trichomonas vaginalis. 

 (When I started my job, I had never heard of this one. And I’d already been teaching sex ed at uni. So no worries if you’re confused. Again, around half of people don’t get symptoms for this one. It’s rarer in men (FPA, 2019).

  • Mainly spread through unprotected vaginal sex, affecting the vagina or urethra
  • Symptoms: burning during urination, discharge (can be frothy, yellow, thick, thin, strong smell), itches, pain from soreness/inflammation. They can show up a month after contracting
  • Testing: can be asap if you’ve been in contact with someone you think might have trichomoniasis. Swab in the vagina, or tip of the penis. They can be looked at under a microscope in real-time or sent off for testing. Takes 10 days
  • Treatment: antibiotics. Can be one dose or over a week

7. Scabies: Parasitic (tiny mites) Can take 6 weeks for symptoms to show (FPA, 2019).

  • Passed on with close body/sexual contact with someone who already has scabies. They live for up to 72 hours away from the body, so can exist on clothing/bedding
  • Symptoms: itching (often noticed at night), itchy red rash, tiny spots, inflammation, broken skin
  • Again, if you think you might have it, get a checkup ASAP. Can be tested visually/microscopically. Likely to receive treatment immediately even if it’s only suspected
  • Treatment: neck-down whole body overnight lotion treatment for 12 hours. Hot wash affected clothing/materials

8. Public lice: Parasitic. Sometimes called crabs. Tiny lice that live in pubic hair (Brook, 2020).

  • Can take weeks to show symptoms. It is less frequently passed on through oral sex (NHS, 2018)
  • Symptoms: itching in affected areas. Brown eggs, sky-blue spots after a few days, tiny specks of blood (ibid)
  • These can be found in the hair on the body such as on the armpits, legs, chest, but they are different to head lice (FPA, 2019)
  • ASAP testing again like with scabies
  • Treatment: lotions/shampoos/cream for pubic lice. They vary for how long they’re left on, usually need to be repeated within the week – depends on brand etc. (ibid), also need to hot wash things in your house that have made contact with your body

9. Bacterial vaginosis. This can develop after having sex, but isn’t only sex-related. If you have unusual discharge from your vagina, this is thought to be the main cause. Only affects people with vaginas, of which 1 in 3 will get this across their lifetime (FPA, 2019).

  • Symptoms: discharge becomes thin, watery, changes to a different greyer colour and can smell ‘fishy’, which can be amplified after having sex (ibid). See ‘typical’ female discharge info here
  • It can be that people get BV often, and sometimes have to do extensive research to find out the causes
  • Essentially, someone has less of the usual vaginal bacteria – called lactobilli – and the vagina becomes more alkaline (FPA, 2019). When people say people with vaginas shouldn’t use ‘Femfresh’ hygiene products, this is because the vagina cleans itself and usually regulates its own environment (Brochmann & Dahl, 2017)
  • It can, unfortunately, be more common if: you use medicated/perfume soap when cleaning yourself which introduces unfamiliar bacteria, ‘douche’, clean your underwear with a particularly potent laundry cleaner, or you are a smoker (FPA, 2019). It is also thought that: “hormonal changes during the menstrual cycle, receiving oral sex, semen in the vagina after sex without a condom, an intrauterine contraceptive device (IUD) and genetic factors may also play a part” (FPA, 2019)
  • Test: an examination, a swab and/or a pH test of discharge from the vagina
  • Treatment: antibiotics in pill form or creams or gels. Different treatments

10. Thrush. From a “yeast fungus” (FPA, 2019). The fungus inflames mucous membrane (Brochmann & Dahl, 2017), which cause the symptoms. Similar to BV that it doesn’t always come from having sex but can be brought on by increased sexual activity. 75% of people with vaginas will get this over their lifetime. People with penises don’t often get it (FPA, 2019).

  • More likely to get thrush if: wearing tight clothing, synthetic underwear, on antibiotics, pregnancy, chemo, illnesses that affect your immune system. Similar irritants affect BV like feminine hygiene products (ibid)
  • Symptoms: itchiness, feeling sore, red area, fissures (similar to the feeling of paper cuts (ibid)), thick white, “cottage-cheese like discharge” (ibid), the same can happen on the penis, with painful foreskin
  • Test: examination and swab. As some of these symptoms might be similar to other STI’s, it’s good to get tested at the same time
  • Treatment: antifungal cream for your genitals, pessaries (pills inserted into the vagina), pills – or a big ol combination

11. UTIs. these are caused by bacteria from the anus making their way into the urinary tract (includes infection of the bladder, kidneys, urethra (NHS, 2017). 

  • The risk is at least 60% higher than normal in the two days following intercourse for women < 30 (Brochmman & Dahl, 2017)
  • See more: non-gonococcal urethritis, cystitis, urethritis
  • Symptoms: needing to wee a lot, burning when weeing, bloody/smelly/cloudy wee, tummy pain, feeling ill (NHS, 2017)
  • Go and see a GP, they might need a urine sample from you to test; treatment is usually prescribed antibiotics and it should clear up in a few days

12. Hepatitis B. viral. It has flu-like symptoms. It can be long term and is treated with antiviral medication. Blood tests. Longer-term it can affect the liver (Brook, 2020). There are also other forms of Hepatitis (C is most common in the UK but mainly transmitted by the sharing of needles (ibid)). No ‘cure’ if you get a longer-term infection, but it tends to ‘go away’ for most people (NHS, 2019).

13. HIV (human immunodeficiency virus) viral. 108,800 people have HIV in the UK, 7,500 of those are reckoned to be undiagnosed (THT, 2020).

  • The virus stays in the body for your lifetime. There is a difference between HIV (virus) and AIDS – it “stands for acquired immune deficiency syndrome” (FPA, 2019)
  • Testing: blood test checking for antibodies. Window period: 1 – 3 months for the infection to show (Brook, 2020)
  • People get symptoms soon after (two weeks) an infection, called the ‘seroconversion illness’ (Brook, 2020). They can be flu-like, or much more severe like meningitis and other hospitalisable conditions (Brook, 2020; FPA, 2019). Sometimes after this people do not have symptoms for a long time: this causes long term damage where people experience weight loss, more serious “life-threatening illness” (Brook, 2020)
  • As I’m not an HIV expert, see the below: “HIV lives in the blood and some bodily fluids, so to get HIV, one of these fluids from someone with HIV, has to get into your blood. The virus exists in blood, semen (including pre-come) and vaginal fluids. The commonest way for HIV to be transmitted from one person to another is through having unprotected vaginal or anal sex” (Brook, 2020)
  • Rarely transmitted orally but if it was, this could be with an infected person and someone who had a mouth ulcer
  • Now treatable, but there is no long term cure. People can have an “undetectable load” (FPA, 2019) meaning that they can’t pass the virus on if they are on anti-retroviral medication and their infection has been treated and ‘caught’ early. This medication stops the HIV growing and working, which gives the immune system a chance to repair (Brook, 2020)
  • Certain communities more at risk in the UK: MSM (men who have sex with men) and heterosexual Black African people (ibid)
  • PrEP: ”a medication taken by someone who’s HIV negative to prevent them from acquiring HIV. PrEP has proven to be effective for people who are at especially high risk of acquiring HIV” (ibid)
  • PeP: post-exposure, 28 days of strong medication (Brook, 2020)

Where to now?

I hope everyone learned something new, and feels a little more reassured about the various STIs that can be transmitted. Apologies if this information has overwhelmed anyone; it’s kind of a mini dissertation. Shows how much we all need to know, and the more you know, the more powerful you are!

Believe it or not, this isn’t even the FULL list, just the most heard of/tested for. It is thought there are at least over twenty. Check how STI treatment affects having sex/condom use when you go and get treatment; it differs for all of them and depends on the severity of the infection. 

Further, one of my colleagues will do an LGBT sexual health special, so keep your eyes peeled. I hope that in the future, young people persist with their sexual health, even if they are obstacles in their way.


Brochmann, N & Dahl, E. S. (2017). The Wonder Down Under: A user’s guide to the vagina. Great Britain: Yellow Kite

Brook. (2020). Sexually Transmitted Infections. Topics Webpage. (Accessed online: 27/04/2020) 

FPA. (2019). STIs Overview. STIs Webpage. (Accessed online: 27/04/2020)

NHS. (2017). Urinary Tract Infections. Conditions Webpage. (Accessed online: 27/04/2020)

NHS. (2018). What infections can I catch through oral sex? Sexual Health Webpage. (Accessed online: 01/05/2020)

NHS. (2019). Hepatitis B Treatment. Conditions Webpage. (Accessed online: 27/04/2020)

PHE. (2019). Sexually transmitted infections and screening for chlamydia in England, 2018. (Accessed online: 27/04/2020)

THT. (2020). HIV statistics. About HIV webpage. (Accessed online: 27/04/2020)

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