It started as a small sore on the shaft, the labia or just inside the foreskin, probably only a few days ago. It might sting, or it might be so painless that you only noticed it in the shower.
How it feels is the best first clue. A firm, painless sore with a clean base points to a syphilis chancre. A painful, soft sore with ragged edges points to chancroid, which is rare in the UK. Small blisters that turn into shallow, sore patches are most often herpes. A swab or a blood test settles it. You can walk in for a syphilis blood test at 117a Harley Street, seven days a week.
The three sores side by side
- Syphilis chancre
- Usually painless
- Chancroid
- Painful, often quite sore
- Herpes
- Painful or tender, with tingling or itching beforehand
- Syphilis chancre
- Round, firm, clean edge
- Chancroid
- Soft, with ragged or undermined edges
- Herpes
- Small blisters that burst into shallow sore patches
- Syphilis chancre
- Smooth and moist
- Chancroid
- Grey or yellow, may bleed on touch
- Herpes
- Red and shallow
- Syphilis chancre
- Usually one
- Chancroid
- Often several
- Herpes
- Usually a cluster
- Syphilis chancre
- Firm, rubbery, painless
- Chancroid
- Tender, can become large and sore
- Herpes
- Tender, mostly in a first episode
- Syphilis chancre
- About three weeks after contact (10 to 90 days)
- Chancroid
- Within about a week of contact
- Herpes
- Usually within two weeks of contact
- Syphilis chancre
- Heals alone in three to six weeks, while the infection stays
- Chancroid
- Carries on until treated
- Herpes
- First episode two to three weeks, and it can come back
| Syphilis chancre | Chancroid | Herpes | |
|---|---|---|---|
| Pain | Usually painless | Painful, often quite sore | Painful or tender, with tingling or itching beforehand |
| Edge and feel | Round, firm, clean edge | Soft, with ragged or undermined edges | Small blisters that burst into shallow sore patches |
| Base | Smooth and moist | Grey or yellow, may bleed on touch | Red and shallow |
| How many | Usually one | Often several | Usually a cluster |
| Groin glands | Firm, rubbery, painless | Tender, can become large and sore | Tender, mostly in a first episode |
| When it appears | About three weeks after contact (10 to 90 days) | Within about a week of contact | Usually within two weeks of contact |
| How long it lasts | Heals alone in three to six weeks, while the infection stays | Carries on until treated | First episode two to three weeks, and it can come back |
Use the table as a guide to what the doctor looks for. Real sores often break the pattern. A herpes sore can be single, a chancre can be tender if it has been rubbed, and a sore inside the vagina, anus or mouth may never be seen at all.
Pain: the clue people ignore
Painless is the part that catches people out. A chancre can look like a graze or an ingrown hair, so it gets left alone. It fades within weeks while the infection carries on. Our pages on syphilis symptoms in men and syphilis symptoms in women cover where it appears and what follows.
"A syphilis sore doesn't hurt, which is why people ignore it. If you've got a new sore down there, even one that seems to be healing, come in and let me have a look."
Dr Mohammad Bakhtiar, Clinical Lead, GMC 4694470
Where chancroid fits in the UK
Chancroid is caused by a bacterium called Haemophilus ducreyi. It is rare in the UK, so most painful sores here turn out to be herpes. It can still come up after sex abroad, which is why we can test for it.
What we do when you come in with a sore
The doctor looks first, in a private room. You'll be asked when the sore appeared and what kind of contact you had. The position and look of a sore narrow things down faster than any online guide.
If the sore is open, the doctor can swab it, which takes a few seconds. The swab options are:
- Syphilis PCR from the sore: £196.25, result in 5 days
- Chancroid (Haemophilus ducreyi) PCR: £225, result in 7 days
- Herpes PCR swab: £120.63, result within 3 working days
You will usually have a blood test as well. Our syphilis blood test is a treponemal antibody screen (IgG and IgM by EIA) at £85 plus the £50 blood draw, £135 in total, with the result in 24 hours. The blood test can take a few weeks to turn positive after contact. For a sore only days old, the swab is often the quicker answer. A herpes blood test is £103.75 plus the blood draw, but while the sore is there, the swab tells you more.
A sore can come with other infections, so a wider check often makes sense. Our STI screening packages cover that. The same-day STI test gives results in about six hours.
If the result is syphilis
Syphilis is treated with an antibiotic injection given here at the clinic. It is usually done at a second visit, once your result is back, rather than on the day you are tested. Treatment is £275, consultation and medication included, and charged separately from the test. A follow-up blood test afterwards shows that the treatment has worked.
Every visit is confidential, and you can give a first name only. Read more about private STI testing in London.
Book a look at the sore
Walk in at 117a Harley Street (Monday to Friday 09:00 to 18:00, Saturday and Sunday 10:00 to 14:00), or book a syphilis blood test online. The doctor will examine the sore, swab it if it is open, and explain which results to expect and when.