Chancroid: The Painful Ulcer That Isn't Syphilis
A painful, soft genital sore with ragged edges. Not the painless, firm sore of syphilis. Not the clusters of blisters from herpes. Chancroid is caused by a different bacterium entirely, and knowing which ulcer you have determines the treatment. Still present in sub-Saharan Africa. Curable. Major HIV co-factor.
from your doctor
What is chancroid and why does it matter?
Chancroid is caused by the bacterium Haemophilus ducreyi. Symptoms typically appear 4-7 days after exposure. It starts as a small bump that quickly becomes a painful, open ulcer with soft, ragged edges and a grey or yellowish base. Swollen, painful lymph nodes in the groin (buboes) often follow.
Which genital ulcer do I have: chancroid, syphilis, or herpes?
Three STIs cause genital ulcers, and they look different. This table helps you and your doctor narrow down the cause, but only PCR testing gives a definitive answer.
| Chancroid | Syphilis | Herpes | |
|---|---|---|---|
| Pain | Painful | Painless | Painful (burning/tingling) |
| Ulcer appearance | Soft, ragged edges, grey/yellow base, bleeds easily | Firm, round, clean edges, smooth base | Clusters of small blisters, shallow ulcers when burst |
| Number | One or a few | Usually one (chancre) | Multiple small blisters/ulcers |
| Lymph nodes | Painful, swollen (buboes) | Swollen but usually painless | May be swollen |
| Incubation | 4-7 days | 3-90 days (avg 21) | 2-12 days |
| Recurs? | No (curable) | Progresses in stages | Yes (lifelong, recurring outbreaks) |
| Caused by | Haemophilus ducreyi (bacterium) | Treponema pallidum (bacterium) | HSV-1 or HSV-2 (virus) |
| Epicentre test | Large/XL PCR | Express STI (RPR) or XL (PCR) | All PCR packages (Small+) |
"Any genital ulcer needs three things: identification of the cause, an HIV test, and syphilis screening. You cannot reliably tell the difference between chancroid, syphilis, and herpes by looking. PCR gives the answer. The Large panel at Epicentre covers all three ulcer causes in one swab. I always recommend adding an HIV screen at the same visit, because any open genital sore changes your HIV risk profile."Dr. Samantha Naidoo, MB ChB, FCP (SA), Medical Director, Epicentre
Where can I test for chancroid in South Africa?
H. ducreyi is extremely difficult to culture. PCR is the gold standard. Epicentre detects it in the Large and XL PCR packages.
Large Penile/Cervical (14-17 pathogens) ⭐ Includes H. ducreyi
H. ducreyi + gonorrhoea + chlamydia + herpes + syphilis PCR + trich + M. genitalium + Ureaplasma + HPV + more. Best value for genital ulcer investigation.
XL (35 pathogens) Includes H. ducreyi
Complete panel: all STIs including H. ducreyi + BV + Candida + microbiome markers + syphilis PCR.
Chancroid: Your Questions Answered
How is chancroid different from a syphilis sore?
Pain is the key difference. Chancroid ulcers are painful, soft, and bleed easily. Syphilis chancres are painless, firm, and round. Both are genital ulcers, but the bacterium, treatment, and consequences are different. PCR testing distinguishes them definitively. Read the syphilis guide →
Is chancroid common in South Africa?
Chancroid has declined in SA but has not been eliminated. It persists in communities with limited healthcare access. Under-diagnosis is likely because H. ducreyi is difficult to culture and most clinics do not have PCR capability.
Is chancroid curable?
Yes, completely. Treatment from your doctor clears the infection. Ulcers typically heal within 1-2 weeks. Swollen lymph nodes may take longer. Unlike herpes, chancroid does not recur after successful treatment.
Does chancroid increase HIV risk?
Yes, significantly. Open genital ulcers create direct entry and exit points for HIV. In sub-Saharan Africa, genital ulcer disease (including chancroid) has been a major driver of HIV transmission. Read the HIV guide →
Can I have chancroid and syphilis at the same time?
Yes. Co-infection with multiple ulcer-causing STIs is possible. This is why PCR testing is essential rather than clinical diagnosis alone. The Large package tests for chancroid, syphilis, and herpes simultaneously.
What if I have a genital ulcer and am not sure what it is?
Get tested. Do not try to self-diagnose based on appearance. The Large PCR package (R1,925) covers all three ulcer-causing STIs (chancroid, syphilis, herpes) plus additional pathogens. Add HIV screening (R168 standalone or in Express STI) at the same visit.
How much does chancroid testing cost?
Large (includes H. ducreyi): R1,925. XL: R3,305. Students 10% off. Payflex 4× interest-free. Note: Small, Medium, and Express do not include chancroid. View all packages →
Other infections in this guide
Genital Ulcer? Don't Guess. Test.
Chancroid, syphilis, and herpes all cause genital ulcers. Only PCR tells you which one. The Large package covers all three.
