Testing and Treatment for Syphilis

Syphilis is one of the few STIs where treatment is fast, effective, and has barely changed in 80 years. A single injection of penicillin cures early-stage syphilis in the vast majority of cases. The hard part is not treatment. It is getting diagnosed in the first place.

Most private clinics test for syphilis but refer you elsewhere for treatment. Home testing kits detect it but leave you to navigate the NHS system for an injection. We do both under one roof. Test, diagnose, treat - all at 117a Harley Street, usually within 24 to 48 hours.

"Syphilis is completely curable at every stage, but the key is not to delay. Treatment is straightforward — usually a single injection of penicillin — and follow-up blood tests confirm the infection has cleared."

Dr Mohammad Bakhtiar, Sexual Health Physician, GMC 4694470

How is syphilis treated?

The standard treatment for syphilis is an intramuscular injection of benzathine penicillin G (2.4 million units), a single dose that cures primary, secondary, and early latent syphilis in over 95% of cases; this is the same treatment recommended by BASHH, NICE, and the WHO, and we administer it at our clinic.

The treatment depends on the stage of infection:

Stage	Treatment	Doses	Cure rate
Primary syphilis	Benzathine penicillin G 2.4 MU IM	Single injection	>95%
Secondary syphilis	Benzathine penicillin G 2.4 MU IM	Single injection	>95%
Early latent (<2 years)	Benzathine penicillin G 2.4 MU IM	Single injection	>95%
Late latent (>2 years)	Benzathine penicillin G 2.4 MU IM	3 injections, 1 per week	>95%
Neurosyphilis	IV benzylpenicillin (hospital setting)	14-day course	Referral required

For the overwhelming majority of patients we see, treatment is a single injection in one visit.

What happens at our clinic

Here is the actual process, step by step.

Consultation (included in package price or £150 standalone). You see a sexual health doctor who takes a confidential history, discusses your exposure or symptoms, and determines what testing you need. If you have a visible chancre or rash, the doctor may make a clinical assessment during this appointment.

Testing. A blood sample is taken for syphilis serology (IgG/IgM antibodies). If you are testing for syphilis alone, the cost is £85 with results in 24 hours. Most patients opt for a screening package that includes syphilis alongside HIV and other infections, since co-infection is common. Our Bronze Screen (£250) covers HIV, syphilis, chlamydia, and gonorrhoea. Need results faster? The FAST Screen returns syphilis results in 6 hours for £350.

Results. Your doctor contacts you with results, typically the next day. If the result is positive, you are booked in for treatment. In many cases, if clinical suspicion is high (visible chancre, known contact), treatment can begin the same day as testing while awaiting lab confirmation.

Treatment. You come back to the clinic (or stay if same-day treatment is appropriate), and the doctor administers the benzathine penicillin injection. The injection goes into the gluteal muscle. It takes about 30 seconds. Some patients find it uncomfortable for a moment, but it is not particularly painful.

Follow-up. We arrange follow-up blood tests at 3 and 6 months to confirm the infection has cleared. Syphilis serology can remain positive for months or years after successful treatment (this is normal and does not mean treatment has failed). Your doctor will explain what the follow-up results mean.

The entire process, from first consultation to confirmed cure, is managed by the same clinical team. No referrals. No waiting lists. No gaps where you are left wondering what happens next.

Penicillin allergy: what are the alternatives?

If you have a confirmed penicillin allergy, the standard alternatives per BASHH guidelines are:

Doxycycline 100mg twice daily for 14 days (early syphilis) or 28 days (late latent syphilis). This requires strict adherence to a two-week or four-week course of oral antibiotics.

Azithromycin has been used historically but is increasingly unreliable due to macrolide resistance in Treponema pallidum, particularly in the UK. BASHH no longer recommends azithromycin as first-line alternative.

Ceftriaxone (an injectable antibiotic from a different class to penicillin) is sometimes used, though evidence is more limited than for penicillin.

Our doctors will discuss the best option for your situation. If your "penicillin allergy" is based on a childhood report rather than a confirmed anaphylactic reaction, desensitisation and penicillin treatment may still be the safest and most effective route. We can advise on this.

Why treatment timing matters

Syphilis is most easily and completely cured in its early stages. One injection, one visit, and you are done.

As the infection progresses, treatment becomes more involved. Late latent syphilis requires three weekly injections instead of one. Neurosyphilis requires hospital admission for intravenous antibiotics. And any damage done to organs, the cardiovascular system, or the nervous system during late-stage disease may not be fully reversible even after the infection is treated.

The practical message: if you think you might have been exposed, do not wait. A syphilis blood test is £85 and takes 24 hours. The treatment is a single injection. The alternative is an infection that slowly progresses through stages that become harder to manage.

How do I know if I need a syphilis test?

Testing is recommended if:

• A sexual partner has told you they have syphilis
• You have a painless sore on or around your genitals, anus, or mouth
• You have an unexplained rash, particularly if it affects the palms of your hands or soles of your feet
• You have had a new partner or unprotected sex
• You are pregnant or planning pregnancy
• You have been diagnosed with HIV or another STI (syphilis co-infection rates with HIV are high, particularly in MSM populations)
• You are a man who has sex with men (BASHH recommends annual syphilis screening for MSM, or more frequently with multiple partners)
• You have unusual discharge or other unexplained genital symptoms

You do not need a GP referral. Walk in or book online.

Can syphilis come back after treatment?

Treatment cures the infection. It does not provide immunity. You can catch syphilis again through contact with a new (or the same) infectious sore. Reinfection is common, particularly in people with ongoing risk factors.

After treatment, we recommend:

• Follow-up blood tests at 3 and 6 months
• Repeat screening if you have new sexual partners
• Partner notification - informing recent sexual partners so they can be tested and treated, breaking the chain of transmission
• Using condoms consistently, although condoms do not provide complete protection against syphilis because sores can be in areas not covered by a condom

Our doctors can help with partner notification if you need support with that conversation. Discretion is central to how we work.

Syphilis testing and treatment costs

Service	Price	Includes
Syphilis blood test (standalone)	£85	Test only
Consultation + syphilis test	£150 + £85	Doctor consultation + test
Bronze Screen	£250	Consultation + HIV, syphilis, chlamydia, gonorrhoea
Silver Screen	£325 (M) / £375 (F)	Consultation + 9-11 infections
Gold Screen	£475 (M) / £490 (F)	Consultation + 11+ infections + hepatitis
FAST Screen Simple	£350	6-hour results: HIV, syphilis, chlamydia, gonorrhoea
Treatment (penicillin injection)	Included with consultation	Single injection administered at clinic

When you book a screening package, the consultation fee (£150) is included. If your result is positive and you need treatment, the injection is administered at the clinic with no additional charge beyond the consultation.

All testing uses UKAS-accredited laboratories. We are open six days a week and accept walk-ins, pseudonymous registration, and cash payment.

Why choose our clinic for syphilis treatment?

Most private clinics and virtually all home testing services are test-only. You get a positive result, and then you need to find a GUM clinic, wait for an NHS appointment, and start the process over again with a new clinician who does not have your history.

We diagnose and treat in the same building, with the same doctor, often within 24 to 48 hours. For patients who are anxious, symptomatic, or simply want the problem solved quickly, that continuity matters.

We also see patients who have had unclear results from other providers. Home test kits can produce equivocal syphilis results that need clinical interpretation. If you have been tested elsewhere and are not confident in the result, we can provide a definitive answer and immediate treatment if needed.

Frequently asked questions

How soon after treatment is syphilis cured?

The bacteria are killed rapidly after the penicillin injection, typically within days. However, blood test markers (RPR/VDRL titres) take 3 to 6 months to decline, and some antibody markers remain positive for life. Your follow-up blood tests at 3 and 6 months confirm the titres are falling, which indicates successful treatment. Your doctor will explain what the numbers mean.

Can I have sex during syphilis treatment?

BASHH recommends avoiding sexual contact until the primary chancre or secondary rash has fully healed and you have completed treatment. For early syphilis treated with a single injection, most doctors advise waiting at least 2 weeks after treatment before resuming sexual activity. Partners should also be tested and treated.

Is the syphilis injection painful?

Most patients describe it as uncomfortable rather than painful. The injection is intramuscular (into the gluteal muscle), and the medication is viscous, so it takes a moment to administer. Discomfort typically fades within a few minutes. The entire injection takes about 30 seconds.

What if I am pregnant and have syphilis?

Syphilis during pregnancy requires prompt treatment to prevent congenital syphilis. Benzathine penicillin G is safe during pregnancy and is the recommended treatment. If you are pregnant and believe you may have been exposed, contact us immediately. Early treatment protects both mother and baby. The syphilis symptoms in women page explains why syphilis is particularly easy to miss in women.

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Need syphilis testing or treatment? We test, diagnose, and treat under one roof at 117a Harley Street. Results in 24 hours. Injection treatment on-site. Walk in or book online.

References

• BASHH (2024). UK National Guidelines on the Management of Syphilis.
• NICE CKS (2024). Syphilis — Management.
• WHO (2024). Syphilis — Key facts.