What Are the Risks and Side Effects of Occipital Nerve Blocks?

Occipital nerve blocks are among the safer procedures in headache medicine, with most side effects being mild and short-lived. The most common complaints are soreness, numbness, or tingling around the injection site, and these typically resolve within a few days. Serious complications exist but are genuinely rare, and they tend to cluster around specific circumstances: the addition of corticosteroids to the injection, accidental entry into a blood vessel, or infection from poor technique. Understanding which risks are routine nuisances and which are worth a real conversation with your provider is what makes the difference.

The Everyday Side Effects Most People Experience

The side effects that show up most often after an occipital nerve block are the ones you would expect from any injection near the back of the head. Tenderness at the injection site, localized numbness, tingling in the area around where the needle went in, and minor bleeding or swelling top the list. A study that compared lidocaine injections with saline injections in chronic migraine patients found that roughly two-thirds to three-quarters of patients in both groups reported at least one side effect, and the three most common in both arms were injection site bleeding, pain, and swelling, all resolving within days.¹ The fact that the saline group had a nearly identical rate of complaints tells you something useful: much of the discomfort comes from the needle itself, not the medication.

Transient numbness spreading beyond the immediate injection area is also common. About 8% of patients in one trial reported head numbness that lasted less than 48 hours after a greater occipital nerve block.¹ Some people describe a strange sensation of numbness radiating into the forehead or face in the minutes after the procedure. In a large study of over 1,500 injections, 12 patients reported immediate symptoms in their face or tongue, likely triggered by nerve pathways connecting the occipital region to facial sensation rather than by anything going wrong with the injection itself.² These sensations are startling if you are not expecting them but wear off quickly.

Vasovagal Reactions and Feeling Faint

Fainting or near-fainting is the most frequently recorded immediate complication. In that same dataset of 1,577 injections, syncope or near-syncope was the leading immediate adverse event, accounting for most of the 32 cases where something went noticeably wrong right away.² A vasovagal response is your body’s overreaction to pain or stress: blood pressure drops, heart rate slows, and you feel lightheaded or actually pass out for a moment.

This is not unique to occipital nerve blocks. It happens with blood draws, dental injections, and other minor procedures. But the back of the head is a sensitive area, and the combination of needle anxiety and the unusual position (some providers have you sit upright, others have you lean forward) can make it more likely. If you have a history of fainting during medical procedures, mention it beforehand. Most clinics will have you sit or lie down for a few minutes after the injection to make sure you are stable. Dizziness and lightheadedness that do not progress to actual fainting are also regularly reported.³

What Happens When Steroids Are in the Mix

Many occipital nerve blocks use only a local anesthetic like lidocaine or bupivacaine. But some providers add a corticosteroid, such as triamcinolone, methylprednisolone, or dexamethasone, especially for cluster headaches or cervicogenic headaches. This is where a distinct set of risks enters the picture, and it is worth knowing that adding a steroid has not been shown to further reduce migraine frequency or pain intensity compared with local anesthetic alone.¹

The most visible steroid-related side effects are changes to the skin and hair at the injection site. Corticosteroids constrict small blood vessels in the skin, slow collagen production, and can thin the skin enough to create a visible depression. They also suppress hair growth in the area, sometimes causing a noticeable bald patch. Four patients who received greater occipital nerve blocks with triamcinolone and lidocaine developed both skin thinning and hair loss at the injection site, prompting the authors to suggest that other steroid preparations might be safer choices for this particular location.⁴ The underlying mechanism involves steroid crystals deposited at the site that constrict local blood supply, inhibit skin cell turnover, and reduce the production of structural proteins in the skin.⁵ At least one clinical trial had to stop enrolling patients into the steroid arm specifically because skin atrophy and hair loss became intolerable.¹

A far rarer but more serious steroid risk is Cushing syndrome, the body’s response to excessive cortisol. Only one case has been reported in the literature: a woman who received six bilateral occipital nerve blocks with 40 mg of triamcinolone each over three months developed signs of the condition.¹ While a single case report does not mean this is a common hazard, it highlights why providers should be cautious about repeating steroid-containing injections on a tight schedule. Other steroid-related complaints that have been noted include fat redistribution, steroid acne, and oral thrush.³

Temporary Facial Nerve Palsy

One of the more alarming possible side effects is temporary weakness or paralysis on one side of the face, caused by the anesthetic accidentally reaching the facial nerve. A patient who received a block of both the greater and lesser occipital nerves with bupivacaine and triamcinolone developed complete facial nerve palsy on the same side within minutes of the injection.⁶ The most likely explanation is that the anesthetic solution spread along tissue planes from the injection site toward the facial nerve. The position of the patient, the volume injected, and the potency of the anesthetic all seem to play a role.

The lesser occipital nerve block site sits particularly close to where a branch of the facial nerve exits near the ear, making that injection point the more probable culprit when facial palsy occurs.⁷ The good news is that these episodes are transient. They resolve as the anesthetic wears off, usually within hours. But experiencing sudden drooping on one side of your face can be terrifying if nobody warned you it was possible, and it can mimic a stroke. Knowing this is a recognized, temporary complication helps avoid a panicked emergency room visit.

In a study of repeated occipital nerve blocks for eye-related nerve pain, transient facial numbness was noted in two of the patients who experienced side effects, alongside four cases of neuritis, or nerve irritation.⁸

Accidental Intravascular Injection

The greater occipital nerve runs close to the occipital artery for much of its course toward the scalp.⁹ That close proximity means there is always a small risk of accidentally injecting the anesthetic into a blood vessel instead of around the nerve. When local anesthetics enter the bloodstream, they can cause local anesthetic systemic toxicity, which ranges from mild symptoms like perioral numbness and slurred speech to seizures and cardiac arrest at the extreme end.

A case report describes a 34-year-old woman who developed slurred speech and numbness around her mouth within a minute of receiving a bupivacaine injection for a greater and third occipital nerve block. This happened despite the use of ultrasound guidance and repeated checks to make sure the needle was not in a blood vessel.¹⁰ She was treated promptly with an intravenous lipid solution, which is the standard rescue for this type of toxicity. The case underscores that ultrasound and aspiration tests reduce the risk but do not eliminate it entirely, because the cervical region has a dense web of blood vessels close to the skin surface.

Systemic toxicity from occipital nerve blocks remains extremely rare. The volumes of anesthetic used are small, typically not exceeding 4 mL per nerve, which keeps the total dose well below the toxic threshold for most patients. Still, it is one of the reasons many clinicians prefer lidocaine over bupivacaine for this procedure: lidocaine has a wider safety margin and a shorter duration of action, so if it does reach the bloodstream, the window of danger is narrower. Research has not found a meaningful difference in pain relief between the two anesthetics for this specific procedure.¹

Infection Is Rare but Has Been Severe

Any time a needle breaks the skin, there is a theoretical risk of introducing bacteria. For occipital nerve blocks, infection is vanishingly uncommon with proper sterile technique. But at least one case illustrates how serious it can become when things go wrong. A patient who received two occipital nerve blocks with methylprednisolone and xylocaine, 11 days apart, developed a growing, tender swelling at the injection site. Sixteen days after the second block, imaging revealed a subcutaneous abscess, an epidural abscess (a collection of pus between the skull and brain lining), and focal erosion of the skull bone between the two collections.¹¹ The patient required intensive care, intravenous antibiotics, and likely surgical intervention.

This case is a worst-case outlier, not a typical risk. But it is worth knowing that any worsening pain, growing swelling, redness, warmth, or fever at the injection site after the procedure warrants urgent medical attention rather than a wait-and-see approach. The use of corticosteroids in the injection may have contributed, since steroids suppress local immune responses and can make it easier for bacteria to establish an infection.

Occipital Nerve Blocks During Pregnancy

Headache management during pregnancy is tricky because many standard medications are off-limits. Occipital nerve blocks have emerged as one of the safer options, and the limited evidence so far is reassuring. A randomized trial comparing occipital nerve blocks with acetaminophen plus caffeine for headache treatment in pregnant patients found no significant differences in complications between the two groups.¹² The nerve-block group did deliver slightly earlier on average, but there was no significant difference in preterm birth rates.

A separate retrospective study surveyed 21 pregnant migraine patients who had received occipital nerve blocks. None of the surveyed patients reported significant pregnancy complications, negative fetal outcomes, or an increased rate of miscarriage.¹³ These are small numbers, so they should not be read as a guarantee. But they do suggest that the procedure itself does not introduce obvious new dangers for the pregnancy. When steroids are used in pregnancy, the calculus shifts, since systemic steroid exposure carries its own set of fetal considerations, and many providers avoid adding them during pregnancy.

What Happens with Repeated Injections Over Time

Many headache conditions are chronic, and a single occipital nerve block provides only temporary relief, typically lasting weeks to a couple of months. That naturally raises the question of whether getting repeated blocks introduces cumulative risks. The evidence here is limited but suggests that repeated injections remain safe as long as the steroid component is managed carefully.

A prospective study of greater occipital nerve blocks in chronic cluster headache patients tracked outcomes through up to four rounds of injections. Response rates stayed relatively consistent across the second, third, and fourth injections, with about 6% of patients experiencing a transient worsening of their headaches after the procedure.¹⁴ That temporary flare is worth mentioning to your provider if it happens, but it is not a sign that the treatment is failing or causing damage.

In patients with ocular neuropathic pain who received repeated blocks, seven out of the group experienced adverse events, including neuritis (nerve irritation) in four cases and transient facial numbness in two.⁸ Neuritis is a more concerning finding than simple injection-site soreness, since it implies the nerve itself is becoming irritated, possibly from repeated needle trauma or from the medications being deposited nearby.

A randomized trial comparing repeated occipital nerve blocks with pulsed radiofrequency therapy for chronic migraine found that both approaches significantly reduced pain scores and disability at one month, but the radiofrequency group maintained better results at six months.¹⁵ This does not mean the blocks are unsafe over time, but it suggests that for patients needing very frequent repeat procedures, other approaches might offer longer-lasting relief and reduce the total number of injections needed.

The Initial Headache Flare Nobody Warns You About

One side effect that catches people off guard is having your headache temporarily get worse right after the block. It seems counterintuitive: you came in for pain relief, and for the first day or two, your head hurts more. This transient worsening has been documented across several studies. In the large 1,577-injection dataset, persistent pain at the injection site was the most common delayed adverse effect, reported in a subset of the 145 patients who had delayed side effects out of 1,380 followed up.² The 6% transient worsening rate in the cluster headache study noted earlier reflects a similar pattern.¹⁴

The flare likely results from a combination of the mechanical trauma of the needle, local swelling from the injected volume, and possibly a brief rebound as the anesthetic wears off before the anti-inflammatory effect of any steroid kicks in. It does not mean the block failed. Most providers counsel patients to give it 48 to 72 hours before judging whether the procedure worked.

Landmark Technique Versus Ultrasound Guidance

Occipital nerve blocks can be performed using anatomical landmarks alone or with the help of ultrasound. You might assume that ultrasound-guided blocks are always safer, but the picture is not quite that straightforward. A randomized trial comparing landmark-guided blocks at the traditional injection point with ultrasound-guided blocks at a different anatomical level found no serious adverse events in either group.¹⁶ The systemic toxicity case described earlier occurred even with ultrasound guidance and negative aspiration checks, reinforcing that imaging reduces risk without eliminating it.¹⁰

In practice, the landmark technique is more commonly used in office settings because it is quick, requires no special equipment, and the anatomy of the greater occipital nerve at the back of the skull is relatively predictable. Ultrasound may be preferred when the anatomy is unusual, when targeting the third occipital nerve in addition to the greater one, or when the patient has had an unexpectedly poor result from a landmark-guided attempt. Neither approach has been shown to produce meaningfully different safety profiles in the research published so far.

Less Common Side Effects Worth Knowing About

Beyond the side effects already covered, open-label studies have compiled a long list of infrequent adverse events reported after occipital nerve blocks. These include neck stiffness, transient difficulty swallowing, a quieter-than-usual voice, nausea, brief heart palpitations, sleep disturbances, facial swelling, and what has been described as pseudoseizure activity.³ None of these are common, and many have been reported only once or twice across large datasets. Allergic reactions to the anesthetic or steroid are possible but rare with the agents typically used.

Neck stiffness and transient torticollis (an involuntary head tilt) likely result from the anesthetic spreading to nearby muscles. Difficulty swallowing or a hoarse voice suggests the medication reached nerves that control throat muscles, which can happen when the injection is placed somewhat lower or deeper than intended. These effects resolve as the anesthetic wears off, usually within a few hours.

1
PubMed Central. Occipital nerve block for headaches: a narrative review
2
Annals of Headache Medicine. Greater Occipital Nerve Blockade: Safety, Adverse Effects, and Patient Outcomes In 1577 Injections
3
Neurology India. Role of Greater Occipital Nerve Block in Headache Disorders
4
PubMed. Cutaneous atrophy and alopecia after greater occipital nerve injection using triamcinolone
5
PubMed Central. Alopecia and cutaneous atrophy due to occipital nerve block containing steroids
6
PubMed. Transient facial nerve palsy after occipital nerve block: a case report
7
Annals of Headache Medicine. Facial Nerve Palsy After Occipital Nerve Blocks — A Case Report
8
PubMed Central. Effect of Repeated Greater Occipital Nerve Block in Patients with Ocular Neuropathic Pain: A Retrospective Observational Study
9
Alexandria Journal of Medicine. Surgical anatomy of greater occipital nerve and its relation to occipital artery
10
Kocaeli Medical Journal. Local Anesthesia Systemic Toxicity After Greater Occipital Nerve + Third Occipital Nerve Block
11
PubMed Central. Occipital osteomylelitis and epidural abscess after occipital nerve block: A case report
12
PubMed Central. Occipital Nerve Block Compared With Acetaminophen and Caffeine for Headache Treatment in Pregnancy: A Randomized Controlled Trial
13
PubMed Central. A retrospective cohort study to evaluate the effectiveness and safety profile of occipital nerve blocks in the treatment of migraine during pregnancy
14
PubMed. Greater occipital nerve blocks in chronic cluster headache: a prospective open-label study
15
PubMed Central. Comparison of the efficacy of repeated greater occipital nerve block and pulsed radiofrequency therapy in chronic migraine patients: a randomized controlled study
16
PubMed. Comparative Effectiveness of Landmark-guided Greater Occipital Nerve (GON) Block at the Superior Nuchal Line Versus Ultrasound-guided GON Block at the Level of C2: A Randomized Clinical Trial (RCT)