Sexually Transmitted Infections (STIs) in Men: Complete List of Symptoms, Types & Treatments | Doctor-Reviewed [2026]

Types of STIs Every Man Should Know [Overview Table]

The STIs that men commonly contract are broadly classified into bacterial, viral, and protozoal infections by the causative pathogen. In each case the primary route of transmission is sexual contact, but symptom presentation, incubation periods, and treatment differ greatly.

Bottom line: the main STIs that men should be aware of in daily life are the following 7 types. They are listed in order of the highest reported case numbers and clinical importance.

Comparison of 7 Major STIs | Incubation, Symptoms, Treatment

*Beyond these, hepatitis B/C, amebiasis, LGV, scabies, and pediculosis pubis can also be transmitted through sexual contact.

Key point: As soon as you suspect “this might be an STI,” it’s important to get tested regardless of whether you have symptoms. Even mild Chlamydia, gonorrhea, syphilis, and HIV can lead to serious complications (epididymitis, infertility, neurosyphilis, AIDS) if left untreated.

3 Reasons STIs Are Increasing in Japan

In recent years, reported syphilis cases in Japan have surged. According to National Institute of Infectious Diseases data, cases have risen steadily since the late 2010s, exceeding 10,000 in 2022 — the highest on record. Three factors lie behind this trend:

• Expansion of encounters through SNS and dating apps: Easier to have sexual contact with multiple partners in a short time, accelerating transmission
• Rise in asymptomatic carriers: Chlamydia, syphilis, and HIV often have long asymptomatic periods, so people unknowingly spread infection to partners
• Low testing uptake: Stigma and embarrassment around STIs mean many people skip testing even when symptomatic. Japan’s HIV testing rate is low compared with Western countries

Given this backdrop, “get tested regularly even without symptoms” and “always see a doctor after concerning contact” are the best ways to protect yourself and your partner.

STIs to Suspect by Symptoms | Body-Part Checklist

By the location and form of symptoms, you can narrow STIs down to a degree. However, similar symptoms can be caused by multiple STIs, and co-infection (simultaneous infection with several STIs) is not uncommon. The final diagnosis must always be made at a medical facility.

Symptom & Site | Suspected STIs

*This table is a reference only — do not self-diagnose. If something feels different, please consult a clinic early.

When Testing Is Needed Even Without Symptoms

STIs can be present even without symptoms. If any of the following applies to you, testing is strongly recommended regardless of symptoms.

• You have had sexual contact with multiple/unspecified partners
• Before or after sexual contact with a new partner
• Your partner has been diagnosed with an STI
• You had sexual contact without a condom
• You had oral or anal sex (pharyngeal/rectal infection risk)
• You have had STIs in the past
• You want a regular health check (1-2 times per year is a guideline)

For some STIs, a window period applies — a waiting time until tests turn positive after exposure. Chlamydia and gonorrhea: 1-2 weeks; syphilis: 4-6 weeks; HIV antigen/antibody testing: roughly 4 weeks after exposure.

Chlamydia Infection | The Most Common STI in Men

Chlamydia infection has the highest number of reported cases of any STI in Japan. The causative bacterium, Chlamydia trachomatis, causes urethritis, epididymitis, proctitis, and pharyngitis in men.

A key feature of male Chlamydia is that symptoms are often mild or absent. Infected men frequently transmit the infection to partners without realizing it, and because Chlamydia can cause infertility in women, proactive testing is important for men too. For details, see our article on Chlamydia symptoms in men.

Chlamydia: Symptoms, Incubation, Treatment

• Incubation: 1-3 weeks after exposure
• Main symptoms: Mild painful urination, clear-to-white urethral discharge, itching/discomfort in the urethra (about 50% are asymptomatic)
• Complications: Epididymitis (scrotal swelling, pain, fever); rarely reactive arthritis
• Testing: Urine test (PCR or SDA) or nucleic acid amplification testing of urethral discharge
• Treatment: Azithromycin 1g single oral dose, or doxycycline 100mg twice daily for 7 days
• Treatment course: Typically eliminated within a week; retesting is recommended 3-4 weeks after treatment ends

Chlamydia is cured in nearly 100% of cases with appropriate antibiotic therapy. However, unless your partner is also treated simultaneously, “ping-pong reinfection” recurs — make sure partners are treated in parallel.

Gonorrhea | Severe Painful Urination and Pus

Gonorrhea is a bacterial STI caused by Neisseria gonorrhoeae, and is the second most commonly reported STI after Chlamydia. In men, symptoms are often pronounced: severe painful urination and yellow-white pus appear 2-7 days after exposure.

Co-infection of Chlamydia and gonorrhea is common — about 20-30% of cases involve both. For details, see male gonorrhea symptoms and the difference between gonorrhea and Chlamydia.

Gonorrhea: Symptoms, Incubation, Treatment

• Incubation: 2-7 days after exposure (shorter than Chlamydia)
• Main symptoms: Severe painful urination, thick yellow-white to yellow-green pus, urethral meatus redness/swelling
• Complications: Epididymitis; rarely disseminated gonococcal infection (arthritis, skin lesions)
• Pharyngeal/rectal infection: Oral/anal sex can lead to pharyngeal or rectal gonorrhea (often asymptomatic)
• Testing: Nucleic acid amplification test (NAAT/PCR), culture (to check drug resistance)
• Treatment: Ceftriaxone 1g single IV or IM dose (injection is first-line)
• Watch for resistance: Oral resistance is rising. Injection therapy is recommended for reliable cure

Gonorrhea has shown rapidly increasing resistance to oral antibiotics in recent years, and the WHO has issued warnings. Japanese guidelines also recommend injection therapy as the standard.

If you suspect an STI, start with a test (online consultation available, no initial consultation fee)

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*Initial and follow-up consultations are free. Online consultation is also supported.

Syphilis | Sharply Rising, with Systemic Complications If Untreated

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum that has been increasing explosively in Japan recently. Cases have risen steadily since the late 2010s, exceeding 10,000 in 2022 — the highest on record.

Syphilis is characterized by symptoms that “appear and disappear” while the disease progresses. It moves through Primary (3 weeks after exposure) -> Secondary (3 months later) -> Latent -> Tertiary (years to over a decade later), eventually leading to cardiovascular and neurologic complications (neurosyphilis, cardiovascular syphilis). For details, see our article on syphilis symptoms and treatment.

Syphilis Stages | Symptoms in Stage 1-3

The greatest danger is thinking “I am cured because the symptoms went away” and ignoring it. Primary and secondary symptoms resolve spontaneously, but the bacterium keeps multiplying inside the body and eventually causes lethal complications.

Syphilis Testing & Treatment | Penicillin Is First-Line

• Testing: Blood test (RPR, TPHA, FTA-ABS). Positive 4-6 weeks after exposure
• First-line treatment: Benzathine benzylpenicillin (long-acting penicillin) IM injection (covered by Japanese national insurance since 2021)
• Conventional treatment: Oral amoxicillin (3 times daily for 4-12 weeks)
• Cure assessment: Blood tests at 1, 3, 6, and 12 months after treatment (confirm RPR titer decrease)
• Partner testing: All partners from the past 3 months should be tested

Syphilis can be completely cured with antibiotics if treated early. Detection and treatment before progression to neurosyphilis or cardiovascular syphilis is critically important.

Genital Herpes | Recurring Blisters and Ulcers

Genital herpes is an infection caused by herpes simplex virus (HSV-1 or HSV-2). Blisters and ulcers form on the genitals with severe pain. Once infected, the virus stays latent in nerve ganglia and reactivates with triggers like illness, stress, UV exposure, or sexual activity.

First-episode symptoms are intense and can include fever, general fatigue, and inguinal lymph node swelling. Recurrences tend to be milder. See our article on genital herpes for full details.

Genital Herpes: Symptoms, Incubation, Treatment

• Incubation: 2-10 days after exposure (first episode)
• First-episode symptoms: Small blisters on glans/penis/foreskin, then ulceration, severe pain, fever, inguinal lymph node swelling
• Recurrence symptoms: Blisters/ulcers in the same area but milder. Discomfort/itching may precede
• Testing: Antigen or PCR test from the lesion; blood test (HSV IgG, IgM antibodies)
• Treatment: Oral antiviral drugs such as valacyclovir (Valtrex) 500mg twice daily for 5-10 days
• Suppressive therapy: For 6+ recurrences/year, daily valacyclovir 500mg can suppress flares

For genital herpes, there is no treatment that fully eliminates the virus from the body — antiviral drugs aim to relieve symptoms and suppress recurrence. Starting treatment early during a recurrence (within 24 hours of symptom onset) can make episodes milder.

Genital Warts | Wart-Like Growths Caused by HPV

Genital warts (condyloma acuminata) is an STI caused by human papillomavirus (HPV, mainly types 6 and 11). Cauliflower-like warts appear on the penis, glans, coronal sulcus, and around the anus. They usually do not cause much pain or itching, but their appearance has a significant psychological impact.

HPV is divided into “high-risk types” (types 16, 18, etc.) that can cause cervical cancer, and “low-risk types” (types 6, 11, etc.) that cause condyloma. See our article on genital warts for full details.

Genital Warts: Symptoms & Treatment

• Incubation: 3 weeks to 8 months (average 2-3 months) after exposure
• Main symptoms: Small warts on penis, glans, coronal sulcus, urethral meatus, around the anus, gradually multiplying and coalescing
• Pain: Usually painless, but larger lesions can cause discomfort/bleeding
• Topical treatment: Imiquimod cream (Beselna cream) 3 times/week for up to 16 weeks
• Physical treatment: Cryotherapy with liquid nitrogen, electrocautery, laser excision, surgical excision
• Recurrence: 25-30% recur after treatment. Follow-up for about 3 months is needed

Genital warts can be prevented with HPV vaccination. In Japan, the 4-valent vaccine (Cervarix, Gardasil) and 9-valent vaccine (Silgard 9) are approved, and men can also receive optional vaccination (self-pay).

STI Testing Methods and Costs | Insurance vs. Self-Pay

As a general rule, STI testing is “insurance-covered if symptomatic” and “self-pay for asymptomatic/elective testing.” Testing methods vary by disease and may combine urine tests, blood tests, discharge testing, and lesion swabs.

Results are usually available in 2-7 days (rapid kits can return same-day results in urgent cases). For preparation, men should typically wait at least 2 hours after urination before a urine test.

STI Test Types & Cost Comparison

*Prices are guideline figures. Costs vary by clinic and the contents of the test set. HIV testing is available anonymously and free at public health centers.

Best Time to Test | Watch the Window Period

STI testing has a “window period” (the time between exposure and when a test can detect infection). Testing too soon after exposure will not give the correct result. Recommended timing by disease is:

• Chlamydia / gonorrhea: 1-2 weeks after exposure (test immediately if symptomatic)
• Syphilis: 4-6 weeks after exposure (may be negative if tested too early)
• HIV (antigen/antibody test): About 4 weeks after exposure (NAT test about 11 days)
• Hepatitis B/C: 1-3 months after exposure
• Genital herpes / warts: When lesions appear

A common recommended pattern is initial testing 1-2 weeks after concerning contact, followed by retesting at 3 months. If you are unsure when to test, please consult a doctor first.

STI Treatment at Men’s Care Clinic

Men’s Care Clinic operates three branches – Shinbashi, Akihabara, and Omotesando – and is a men’s-only clinic. With medical partnership with Toyosu Hospital, we maintain a safe care system and offer comprehensive testing and treatment for STIs.

In response to patients who say “I do not want to be seen by other patients” or “I want to avoid being recognized,” we provide completely appointment-based, private-room consultations, with male-only staff available if requested.

STI Testing & Treatment Flow | From First Visit to Prescription

• STEP1 Booking: Book online or by phone. Same-day appointments possible (insurance for symptomatic, self-pay for asymptomatic)
• STEP2 Interview & exam: A doctor reviews symptoms, contact history, and partner status (privacy guaranteed, about 10-15 min)
• STEP3 Testing: Urine test, blood test, and lesion sampling if needed (sampling performed by doctor or nurse)
• STEP4 Results & treatment: Results in 2-7 days. If positive, appropriate antibiotics or antivirals are prescribed
• STEP5 Retesting: 3-4 weeks after treatment, retest to confirm eradication

Test & Prescribe From Home With Online Consultation

For those who find it “embarrassing to visit a clinic” or “too busy to come in,” online consultation is also available. You can have a video consultation by smartphone or PC and have a test kit shipped to your home, with prescription medication mailed (some conditions excluded).

• Online supported from the first visit
• Test kits and prescriptions ship in plain, unmarked packaging
• Results and prescription can be handled entirely online

*Conditions requiring palpation (such as warts or syphilis) require in-person care.

For STI testing and treatment, choose Men’s Care Clinic /

Appointment-only, strict privacy, no initial/follow-up consultation fee
Shinbashi, Akihabara, Omotesando branches / Online consultation available

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FAQ on Male STIs

Below are common questions from our patients about STI symptoms, testing, and treatment, answered clearly by Men’s Care Clinic physicians.

Q1. What is the most common STI in men?

In Japan, Chlamydia infection has the highest number of reported male STI cases, followed by gonorrhea, genital herpes, genital warts, and syphilis. In particular, syphilis has surged since the late 2010s, exceeding 10,000 cases in 2022 — the highest on record.

Note that many people are infected silently regardless of symptoms. Fewer reported cases does not always mean less infection — regular testing for early detection is essential.

Q2. Can STIs be transmitted through oral sex?

Yes — many STIs can be transmitted through oral sex. Chlamydia and gonorrhea can cause pharyngeal infection (pharyngeal Chlamydia/gonorrhea), which is often asymptomatic and a high-risk transmission route.

Oral sex with someone who has primary-stage syphilis (chancre) on the lip or oral cavity can also transmit syphilis. Genital herpes (HSV-1) can spread mutually between lips and genitals. HIV transmission through oral sex is also not zero.

Condom use is recommended even for oral sex, and if pharyngeal infection is suspected, pharyngeal swab testing is needed.

Q3. Can condoms fully prevent STIs?

Condoms greatly reduce STI risk but do not provide complete prevention. Some STIs are transmitted through contact with areas not covered by a condom (scrotum, mons pubis, around the anus, oral cavity).

• Highly preventable with condoms: Chlamydia, gonorrhea, HIV, hepatitis B/C, trichomoniasis
• Incompletely preventable with condoms: Genital herpes, syphilis, genital warts (skin-to-skin contact transmission is common)
• Can spread via oral/skin contact: Syphilis, HSV, HPV, pediculosis pubis

The best prevention combines “condom use + regular testing + open communication with partners.” HPV vaccination is also effective for HPV prevention.

Q4. When should I get an STI test?

Test timing should account for each disease’s window period (time from exposure to a positive result). Common guidelines are:

• 1-2 weeks after concerning contact: Initial test for Chlamydia/gonorrhea
• 4-6 weeks later: Syphilis and HIV antigen/antibody test
• 3 months later: Final confirmation test of all items (HIV and syphilis confirmation)
• When symptoms appear: Visit immediately (covered by insurance)

If your partner is diagnosed with an STI, get tested and treated immediately regardless of symptoms. This prevents “ping-pong reinfection.”

Q5. Are STI tests covered by insurance?

As a rule, insurance covers testing when symptoms are present, while asymptomatic elective testing is self-pay. Specifically, insurance applies when you have symptoms (painful urination, discharge, blisters, lumps) or have had high-risk contact with a partner diagnosed with an STI.

On the other hand, testing for “I am worried but have no symptoms,” “regular checkups,” or “pre-marital screening” is self-pay. Costs vary by number of items – typically JPY 3,000-8,000 for a single test and JPY 15,000-25,000 for a comprehensive set.

For HIV testing, public health centers nationwide offer anonymous, free testing. This is a good option for those who value anonymity or want to minimize costs.

Q6. How do I confirm an STI has been cured?

After completing antibiotic or antiviral treatment, retesting for “cure confirmation (eradication check)” is needed. Retesting timing by disease:

• Chlamydia/gonorrhea: PCR retest 3-4 weeks after treatment ends
• Syphilis: Measure RPR quantitative titer at 1, 3, 6, 12 months (confirm decrease to one-quarter or less)
• HIV: Antiretroviral therapy continues. Monitor viral load and CD4 count every 3 months
• Genital herpes: Antivirals aim at symptom relief – complete elimination is not possible
• Genital warts: Follow up at 3 months post-treatment to check for recurrence

Do not self-diagnose “cured because symptoms are gone” – always follow the doctor’s instructions and complete retesting.

Q7. Should I tell my partner about an STI?

Yes – be sure to tell your partner and have them tested and treated. If your partner is infected, you will be re-infected through “ping-pong infection” even after you have been treated.

For Chlamydia, gonorrhea, and trichomoniasis, notifying all partners from the past 2 months is recommended. For syphilis and HIV, notification of partners from the past 3 months to 1 year is needed.

If telling partners directly is difficult, “partner notification services” at public health centers or medical facilities are an option. Some services allow anonymous contact, so ask your doctor.

Q8. Is HIV infection curable?

HIV cannot currently be “cured,” but with continuous antiretroviral therapy (ART), it can be controlled – preventing AIDS and allowing nearly normal life. Once feared as a “fatal disease” until the 1990s, HIV has transformed into a manageable chronic condition thanks to advances in treatment.

Continuous appropriate treatment can suppress blood viral load below the detection limit, and in that state (U=U: Undetectable = Untransmittable) sexual transmission risk to partners is effectively zero. Early detection and treatment are critical.

If you have had a concerning exposure, post-exposure prophylaxis (PEP) within 72 hours may prevent infection. Please contact a medical facility urgently.