How is syphilis treated?

The antibiotic penicillin kills syphilis bacteria effectively. A long-acting form of penicillin is injected into a muscle, usually in the buttocks. Long-acting medicine is prepared in a special way so that it is released gradually in the body. That way, there is always enough penicillin available to kill the bacteria over the necessary period of ten days.

To check whether the treatment was successful, a blood test is done four weeks after it ends. That is followed by four check-ups at intervals of three months.

Most of the syphilis bacteria die right at the start of treatment with antibiotics. That means a lot of bacteria are killed all at once. The body may react to that with chills, a fever, headache and more severe skin rashes. To prevent those possible reactions, you will usually be given a steroid tablet or injection half an hour or an hour before starting treatment with antibiotics.

People who are allergic to penicillin can take doxycycline tablets (a different antibiotic medication) for two weeks instead. The antibiotic ceftriaxone is another alternative to penicillin in the treatment of syphilis. It is given through a short daily infusion (drip) over a period of ten days.

It is rare for syphilis to reach a late stage nowadays in Germany and many other countries. But late-stage syphilis can still be treated. Treatment stops the infection and prevents any previous damage from getting worse or any new complications from developing. Antibiotics are used here too – the same ones that are used in early-stage syphilis (usually penicillin). But the treatment takes longer.

Instead of just one long-acting penicillin injection, a total of three injections are given one week apart from each other. If you already have nerve damage (‘neurosyphilis’), you will be given several penicillin injections every day for 10 to 14 days instead – directly into your bloodstream rather than a muscle. If you take doxycycline tablets instead, the treatment lasts four weeks. The ceftriaxone drip treatment is extended to 14 days.

Depending on which complications you have, other treatments might be needed on top of antibiotics. These may include painkillers or medication to prevent seizures.

When treating syphilis in pregnant women and babies, penicillin is also usually the first choice. If they're allergic to penicillin, they can't simply use doxycycline tablets instead, though. Doxycycline can harm unborn babies and young children. Ceftriaxone drips are an alternative option, but they can also cause allergic reactions in people who are allergic to penicillin.

To see whether you might be able to use penicillin after all, doctors will first check whether you are actually allergic to penicillin. If you are, you can have a treatment called allergen-specific immunotherapy to slowly get your body used to the penicillin.