Jarisch-Herxheimer reaction is when you have new or worsening symptoms within a few hours of starting treatment for syphilis or certain other bacterial infections. It’s not an allergic reaction. It usually gets better on its own within 24 hours. Your healthcare provider will let you know if you need to be monitored when starting treatment.
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Jarisch-Herxheimer reaction, or just Herxheimer reaction, is a condition that causes acute flu-like symptoms after starting antibiotics for certain bacterial infections. It’s most common in syphilis. But it can also happen when starting treatment for Lyme disease, leptospirosis and relapsing fever.
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The symptoms of Herxheimer reaction can start within a few hours of taking antibiotics. They typically last up to a day before resolving on their own.
Despite happening soon after taking antibiotics, Herxheimer reaction isn’t an allergic reaction. It’s uncomfortable and might be scary. But it usually isn’t life-threatening, and it doesn’t cause long-term issues. There’s no way to prevent this reaction.
Your existing symptoms may get more intense within a few hours of starting treatment. Or you might have new symptoms. Symptoms include:
Experts think Herxheimer reaction might happen when your immune system responds to dying bacteria releasing toxins. Inflammation from your immune system temporarily causes increased symptoms.
Rarely, Herxheimer reaction can cause serious complications, including:
If you’re pregnant, it can cause you to go into labor early.
If your symptoms worsen when you first start treatment for syphilis or other bacterial infections, your provider will diagnose you with Herxheimer reaction. If it lasts longer than a day or two or continues to worsen, you may need more tests.
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Your provider will let you know what to do if you experience Herxheimer reaction. They might recommend taking over-the-counter pain relievers to help you manage the symptoms. In some cases, they might prescribe a corticosteroid to reduce inflammation or recommend IV fluids.
Contact your provider if your symptoms worsen when you start treatment. They can let you know how to manage them and when you might need to seek medical attention.
Herxheimer reaction usually gets better on its own within 24 hours. It’s rarely life-threatening. If you have certain complications of syphilis or you’re pregnant, your provider will monitor you closely for a serious reaction.
When you’re sick, all you want is to feel better. The idea that symptoms might get worse at first isn’t exactly what you want to hear. Luckily, Herxheimer reaction is temporary, and you should start to feel better within a day or even a few hours. Talk to your provider if you have any concerns.
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