The secondary syphilis rash is a rough, red or reddish-brown eruption that classically appears on the palms and soles but can spread across the trunk and limbs. It's a sign the infection from Treponema pallidum has spread through the bloodstream. The rash usually doesn't itch and fades on its own, but the infection persists until treated with penicillin CDC.
~3 wks; 10–90 days
by stage
| Item | Value |
|---|---|
| Primary sore | painless — ~3 wks; 10–90 days |
| Testing | 2 blood tests |
| Treatment | penicillin — by stage |
| Symptoms fade | ≠ cured |
The essentials: why this rash matters
Syphilis moves in stages, and the rash belongs to the second one. Weeks to a few months after a person catches the bacterium, the original painless chancre of primary syphilis has usually healed and the bacteria have seeded the bloodstream. That bodywide spread produces the secondary rash. For the full picture of how the disease progresses, start with what is syphilis? causes, stages & risks.
The timing trips people up. The first sore is painless and often hidden inside the vagina, anus, or mouth, so it's easy to miss, and it heals whether or not you treat it. The infection keeps burrowing inward even as the sore disappears. The rash behaves the same way: it goes away on its own, but without antibiotics the infection slides into the latent stage and, in some cases, the dangerous tertiary stage.
Syphilis is climbing in the U.S. There were about 53,000 primary-and-secondary cases reported in 2023, and the late or unknown-duration stage jumped from 14 to nearly 30 per 100,000 between 2020 and 2023 CDC AtlasPlus, 2023. Rates aren't evenly spread. In 2023 the highest primary-and-secondary rates were in South Dakota, Washington DC, New Mexico, and Mississippi, several times the national average.
What does the secondary syphilis rash look and feel like?
The hallmark is a rough, red or reddish-brown rash that can appear on the palms of the hands and the soles of the feet, an unusual location that makes a clinician think of syphilis right away, since most common rashes spare those areas. The spots are typically flat or slightly raised, often described as coppery, and they usually don't itch or hurt. The rash can also spread across the chest, back, arms, and legs, or stay faint enough to be overlooked.
The rash rarely travels alone. Secondary syphilis is a whole-body illness, and people commonly notice several of the following at the same time:
- Mucous-membrane lesions — moist, grayish-white patches in the mouth, throat, or genital area that are loaded with bacteria and highly contagious.
- Fever, sore throat, and swollen lymph nodes, which can feel like a lingering viral illness.
- Patchy hair loss, sometimes in a moth-eaten pattern across the scalp.
- Headache, muscle aches, fatigue, and weight loss.
- Wartlike growths in warm, moist areas (condylomata lata) that, like the mucous patches, shed live bacteria.
Because the picture overlaps with so many other conditions, secondary syphilis has long been called a great imitator. A rough rash on the palms and soles combined with fever and swollen glands is a pattern worth flagging to a clinician. For how the symptom timeline differs between people, see syphilis symptoms in men vs women.
When these symptoms fade, you are not cured. As CDC puts it, the symptoms from this stage go away whether or not you receive treatment, and without the right antibiotics the infection moves to the latent and possibly tertiary stages. Syphilis can also invade the eyes or nervous system at any stage, so new vision changes, hearing loss, or neurological symptoms in someone with syphilis are a medical emergency, not a problem reserved for late disease StatPearls.
How is the rash tested and confirmed?
Diagnosis is a simple blood draw, but it takes two tests. A single test can't confirm syphilis on its own. You need a nontreponemal test (RPR or VDRL) and a treponemal test (TP-PA, FTA-ABS, EIA, or CIA), because each catches what the other can miss CDC Lab Recommendations, 2024.
Labs run these in one of two acceptable orders. The traditional algorithm screens with a nontreponemal test first and confirms with a treponemal test. The reverse-sequence algorithm starts with a treponemal test, then runs a quantitative nontreponemal test to confirm and to set a baseline titer. Either approach is valid.
Timing matters in early infection. Antibody tests can read negative during the earliest primary stage. CDC notes antibodies might take up to two weeks to appear after the chancre, which itself shows up roughly three weeks after exposure. By the time the secondary rash arrives, tests are reliably reactive, but if you test very soon after a possible exposure and the result is negative, retest rather than trusting that negative. See when to test after exposure for the windows, and you can get tested when you're ready.
How is secondary syphilis treated?
Penicillin G, given by injection, is the preferred treatment for every stage of syphilis, and there's no oral drug that dependably substitutes CDC Tx Guidelines. For primary, secondary, and early latent syphilis, the standard is benzathine penicillin G 2.4 million units IM in a single dose. The dose then scales with how long the infection has been present.
| Stage | Penicillin regimen |
|---|---|
| Primary, secondary, early latent (acquired within the past year) | Benzathine penicillin G 2.4 million units IM, single dose |
| Late latent / unknown duration, tertiary | Benzathine penicillin G 7.2 million units total — three doses of 2.4 million units IM at 1-week intervals CDC |
| Neuro / ocular / otosyphilis | Aqueous crystalline penicillin G 18–24 million units/day IV for 10–14 days CDC |
The correct product is benzathine penicillin G (Bicillin L-A). The combination product Bicillin C-R (benzathine plus procaine) is not an acceptable substitute and has caused real treatment-failure errors. If you're handed a prescription, confirm the exact product.
Expect a short, alarming-feeling reaction. Within the first 24 hours after treatment, often within a couple of hours, many people get fever, chills, headache, and muscle aches. This is the Jarisch-Herxheimer reaction, caused by dying bacteria releasing inflammatory signals, not an allergy to penicillin. It affects roughly 95% of people treated for secondary syphilis and settles within about a day StatPearls. Knowing it's coming keeps people from abandoning a working treatment.
For penicillin-allergic, non-pregnant patients, doxycycline 100 mg orally twice daily for 14 days treats primary, secondary, and early latent syphilis; late latent or unknown-duration disease requires the longer 28-day course. Azithromycin is not recommended because of resistance. Most penicillin allergy is mislabeled — over 90% of people who believe they're allergic are not.
Cure is confirmed by blood titers, not by feeling better. Clinicians repeat the quantitative nontreponemal test at 6 and 12 months for primary and secondary syphilis. A fourfold or greater drop, say from 1:32 to 1:8, confirms the treatment worked, while a fourfold rise signals reinfection or failure.
How do you prevent syphilis?
The core measures are correct and consistent condom use, mutual monogamy with a partner who has tested negative, and routine screening for those at risk. Screening matters because the early sore is easy to miss and the secondary rash can be subtle.
DoxyPEP is a newer option. Taking 200 mg of doxycycline within 72 hours after sex reduced syphilis acquisition by about 73% in trials, and CDC's 2024 guidance recommends it through shared decision-making for men who have sex with men and transgender women who've had a bacterial STI in the past year CDC DoxyPEP, 2024.
Pregnancy deserves special attention. Congenital syphilis nearly doubled in four years, from 2,163 cases in 2020 to 3,882 in 2023, the highest level in decades, and untreated syphilis in pregnancy harms the baby in 50 to 80% of cases. It's preventable with prenatal screening plus penicillin. A pregnant woman with a true penicillin allergy is desensitized and treated with penicillin anyway, because it's the only treatment that protects the baby. See syphilis in pregnancy for the full protocol.
When should you see a clinician?
See a clinician promptly if you notice a rough rash on your palms or soles, an unexplained body rash with fever and swollen glands, sores or moist patches in the mouth or genitals, or patchy hair loss, especially after a new or untreated partner. Get tested even if a previous sore has healed, since healing doesn't mean cure. Treat any new vision changes, hearing loss, severe headache, or neurological symptoms as a same-day emergency, because syphilis can reach the eyes and nervous system at any stage.