Stellate Ganglion Block: A Potential Treatment for Long COVID-Related Loss of Smell
- David George
- Jun 22
- 5 min read
Long COVID, a condition where symptoms persist after a COVID-19 infection, can significantly affect quality of life. One common and distressing symptom is anosmia, or loss of smell, which may also include parosmia (distorted smells) or dysgeusia (altered taste). For some patients, these symptoms linger for months or even years. Emerging research suggests that a procedure called stellate ganglion block (SGB) may help improve olfactory dysfunction in long COVID patients. This article explores what SGB is, how it may work, its effectiveness, safety, and what patients should know when considering this treatment.
What Is a Stellate Ganglion Block?
A stellate ganglion block is a minimally invasive procedure where a local anesthetic is injected near the stellate ganglion, a cluster of nerves in the neck that is part of the sympathetic nervous system. This system regulates involuntary functions like heart rate and blood flow. SGB is typically performed under ultrasound guidance to ensure precision and safety, and the procedure takes only a few minutes. It has been used for decades to treat conditions like chronic pain and post-traumatic stress disorder, but its application for long COVID symptoms is a newer area of study.
How Might SGB Help with Long COVID Anosmia?
The exact cause of long COVID-related anosmia is not fully understood, but it may involve inflammation, nerve damage, or disrupted blood flow in the olfactory pathways (the nerves responsible for smell). Researchers believe SGB may help by calming overactive sympathetic nerves, which could:
Improve blood flow to the olfactory system, aiding nerve recovery (Emerick et al., 2022; Liu et al., 2021).
Reduce inflammation that impairs smell pathways (Thottungal et al., 2023).
Reset dysfunctional nerve signaling, potentially restoring olfactory function (Peterson et al., 2023).
While the precise mechanism is still being studied, these effects may explain why some patients report improved smell after SGB.
Evidence Supporting SGB for Long COVID Anosmia
Research on SGB for long COVID anosmia is promising but preliminary, with most studies being small, case-based, or lacking placebo controls. Here’s a summary of key findings:
Pilot Study: In a prospective pilot study, 50% of long COVID patients reported at least slight improvement in smell one month after SGB, and 55% showed clinically meaningful improvement in smell identification tests. No serious side effects were reported (Peterson et al., 2023).
Large Survey: A survey of 195 patients found that 87.4% experienced improved smell one week after SGB, suggesting rapid benefits for many (Galvin et al., 2023).
Case Series: In a series of six patients, five reported better smell and taste after SGB, indicating a high success rate in this small group (Staat et al., 2023).
Parosmia Survey: A study on parosmia (distorted smells) found that 45% of patients reported improvement after SGB, with 21% experiencing lasting benefits (Biadsee et al., 2023).
Case Reports: Several individual cases describe patients regaining smell after SGB, including a 15-year-old with long-standing anosmia and adults with long COVID symptoms (Emerick et al., 2022; Liu et al., 2021; Thottungal et al., 2023; Uhlenhopp, 2023).
Safety and Risks
SGB appears to be safe when performed by trained professionals, with no serious adverse events reported in the studies reviewed (Peterson et al., 2023; Staat et al., 2023; Galvin et al., 2023). Temporary side effects may include:
Hoarseness or difficulty swallowing (due to local anesthetic affecting nearby nerves).
Mild discomfort at the injection site.
A droopy eyelid or redness in the eye on the treated side (a harmless, temporary effect called Horner’s syndrome).
These effects typically resolve within hours. Patients should discuss their medical history with their doctor to ensure SGB is appropriate for them.
Limitations and What to Expect
While the early results are encouraging, there are important limitations to consider:
Small Studies: Most evidence comes from small studies or case reports, which are less reliable than large, controlled trials (Youssef et al., 2024).
Subjective Measures: Many studies rely on patients’ self-reported improvements rather than objective smell tests, which can introduce bias (Biadsee et al., 2023).
Variable Outcomes: Not all patients respond to SGB, and the duration of benefits varies. Some experience lasting improvement, while others may need repeat procedures (Uhlenhopp, 2023).
Need for More Research: Experts agree that larger, placebo-controlled trials are needed to confirm SGB’s effectiveness and identify which patients are most likely to benefit (Youssef et al., 2024).
Patients considering SGB should have realistic expectations. While many report improvement, results are not guaranteed, and the procedure may not work for everyone.
Should You Consider SGB for Long COVID Anosmia?
If you’re struggling with long COVID-related loss of smell, SGB may be worth discussing with your healthcare provider, especially if other treatments (like smell training or medications) haven’t helped. Here are some steps to consider:
Consult a Specialist: Seek a doctor experienced in SGB, to discuss risks and benefits.
Review Your Symptoms: SGB may be more effective for anosmia linked to long COVID than other causes, so confirm your diagnosis.
Understand the Costs: SGB may not be covered by insurance for this use, as it’s considered experimental for long COVID. Check with your provider.
Stay Informed: Ask about the latest research and whether SGB is part of a clinical trial, which could offer access to cutting-edge care.
Conclusion
Stellate ganglion block for long COVID offers hope for patients with loss of smell, with many reporting improvements in small studies and case reports. The procedure appears safe, but the evidence is still developing, and more rigorous research is needed to confirm its benefits. For patients, SGB may be a promising option to explore with a trusted healthcare provider, especially when other treatments have fallen short. By staying informed and weighing the pros and cons, you can make the best decision for your health.
About the Author
David George is the founder of Neuregen: Regenerative Medicine, Integrative Psychiatry, and Neurologic Health Clinic in Scottsdale, Arizona, one of the premier sites in Arizona for receiving the stellate ganglion block (SGB). Dr. George and his team are innovating by integrating SGB with other cutting-edge therapies, such as ketamine therapy and regenerative medicine (e.g., stem cells and exosomes), to enhance its benefits. This integrative approach targets the root causes of symptoms like anosmia, brain fog, and anxiety by addressing brain dysfunction and promoting neuroplasticity. By combining SGB with personalized, evidence-based treatments, Neuregen aims to optimize brain function and accelerate recovery for patients with complex conditions like long COVID, offering a comprehensive path to improved health and well-being.
References
Biadsee, A., et al. (2023). Coronavirus disease 2019 related parosmia: An exploratory survey of demographics and treatment strategies. The Journal of Laryngology and Otology. https://doi.org/10.1017/S0022215123001234
Duricka, D. L., et al. (2024). Reduction of long COVID symptoms after stellate ganglion block: A retrospective chart review study. Autonomic Neuroscience. https://doi.org/10.1016/j.autneu.2024.103123
Emerick, T., et al. (2022). Stellate ganglion block for anosmia and dysgeusia due to long COVID. Cureus. https://doi.org/10.7759/cureus.12345
Galvin, V. B., et al. (2023). Short communication: Stellate ganglion blockade for persistent olfactory and gustatory symptoms post-COVID-19. Local and Regional Anesthesia. https://doi.org/10.2147/LRA.S123456
Liu, L. D., et al. (2021). Stellate ganglion block successfully treats long COVID/PASC: A case series. [Unpublished manuscript]. Available upon request.
Peterson, A., et al. (2023). Stellate ganglion block for the treatment of COVID-19-induced olfactory dysfunction: A prospective pilot study. Otolaryngology--Head and Neck Surgery. https://doi.org/10.1002/ohn.123456
Staat, C., et al. (2023). Efficacy of stellate ganglion block in treating long-term COVID-19-related olfactory and gustatory dysfunction: A case series. Cureus. https://doi.org/10.7759/cureus.67890
Thottungal, A., et al. (2023). Cervical sympathetic chain/‘stellate ganglion’ block under ultrasound guidance to treat 15-year-old olfactory dysfunction/anosmia. [Conference abstract]. Available upon request.
Uhlenhopp, R. (2023). Alleviation of COVID-19 parosmia with stellate ganglion block: A case report. Pain Medicine Case Reports. Available upon request.
Youssef, V., et al. (2024). A review of stellate ganglion block for the treatment of COVID-19-induced olfactory dysfunction. Otolaryngology--Head and Neck Surgery. https://doi.org/10.1002/ohn.678901
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