Routine antibiotics are not recommended before epidural steroid injections because the infection risk is extremely low, and the potential harms of unnecessary antibiotics outweigh the benefits. The American Society of Regional Anesthesia (ASRA) states there is no recommendation or evidence supporting antibiotic use before most routine interventional pain injections, including epidural steroid injections, facet blocks, and radiofrequency ablation.
The Infection Risk Is Very Low
Epidural steroid injections are quick, minimally invasive procedures performed with sterile technique. The needle enters and exits within minutes, leaving very little opportunity for bacteria to reach the spinal space. Acute infections after spinal injections occur in roughly 0.01% to 0.1% of cases, or between 1 in 10,000 and 1 in 1,000 procedures.
A large study tracking over 500,000 spinal injections between 2007 and 2015 identified just 52 cases of deep spinal infection within 90 days, yielding an infection rate of 0.01% per injection. At that frequency, giving every patient antibiotics would mean treating thousands of people unnecessarily to potentially prevent a single infection.
Sterile Technique Does the Heavy Lifting
Instead of antibiotics, infection prevention during epidural injections relies on careful sterile preparation. Your skin is cleaned with an antiseptic solution before the needle goes in, and the provider uses sterile gloves and sterile equipment throughout. These precautions are the primary barrier against bacteria entering the injection site.
That said, no method is perfect. Research from the American Society of Anesthesiologists notes that infections can still occur even when aseptic techniques are fully followed. But adding prophylactic antibiotics on top of sterile technique hasn’t been shown to close that gap for simple injection procedures. The evidence simply isn’t there to justify it.
Antibiotics Carry Their Own Risks
Giving antibiotics when they aren’t clearly needed introduces a separate set of problems. Common side effects include nausea, gastrointestinal upset, and yeast infections. More seriously, antibiotics account for up to 20% of drug-related hospital admissions in the U.S. due to allergic reactions. Some patients develop rashes that get permanently mislabeled as a penicillin allergy in their medical records, which can complicate their care for years.
There’s also the broader public health concern. Every unnecessary course of antibiotics contributes to antibiotic resistance, making these drugs less effective when they’re truly needed. And in certain patients, antibiotics can trigger Clostridioides difficile infections, a potentially dangerous gut infection that’s notoriously difficult to treat. For a procedure with a 0.01% infection rate, routinely exposing patients to these risks doesn’t make medical sense.
When Antibiotics Are Recommended
The picture changes for more invasive spinal procedures. ASRA guidelines do recommend prophylactic antibiotics before implantable pain therapies, such as spinal cord stimulators or intrathecal drug pumps. These procedures involve placing a permanent device inside the body, creating a much higher infection risk. For these cases, intravenous antibiotics given one hour before the procedure have been shown to reduce surgical site infections by approximately 50%.
Patients who are colonized with MRSA (a drug-resistant staph bacteria) or at high risk for it may receive a specific antibiotic called vancomycin before implant procedures. Even then, antibiotics are not continued beyond 24 hours after the procedure.
The key distinction is the complexity and duration of the procedure. A simple epidural steroid injection takes minutes and leaves nothing behind in the body. An implant surgery takes longer, involves more tissue disruption, and introduces a foreign object where bacteria can establish themselves. That difference in risk is why the antibiotic recommendations differ so sharply.
Signs of Infection to Watch For
Even though infections after epidural injections are rare, knowing what to look for matters. A spinal epidural abscess, the most serious potential complication, typically causes severe back pain, fever, chills, and swelling or tenderness near the injection site. Symptoms can develop and worsen within hours to days.
If the infection puts pressure on the spinal cord, neurological symptoms may appear: leg weakness, difficulty walking, loss of bladder or bowel control, or numbness in the legs, buttocks, or groin. These symptoms require urgent medical evaluation because delayed treatment can lead to permanent nerve damage. The vast majority of patients will never experience any of this, but recognizing the warning signs early makes a significant difference in outcomes if an infection does develop.