Loss of smell, or olfactory dysfunction, is a common post-Covid-19 phenomenon. This study evaluates two such cases that saw improvement with acupuncture. Acupoint LI20, located on the face beside the nose, improves the sense of smell. Practitioners used this point, along with others, for two patients six months after their diagnosis of COVID-19. Both experienced an improved sense of smell immediately following treatment, with continued improvement to varying degrees with additional sessions.
This result led investigators to conclude that acupuncture effectively treated residual olfactory dysfunction post-Covid. In addition, it may be a new option for patients resistant to Western medical treatment or unable to continue treatment due to adverse effects.
Covid-19 and Loss of Smell
The World Health Organization defines Long Covid as “symptoms that persist for more than two months after onset and cannot be explained by other diagnoses.” Although the characteristic olfactory disturbance due to COVID-19 improves early in most cases, some patients remain affected, significantly impacting their quality of life.
For example, a study in Japan reported that 16 percent of patients continued to have olfactory dysfunction at two months, 10 percent at four months, 8 percent at six months, and 1 percent at twelve months. In Italy, a study reported that 13 percent of patients still had a loss of smell after 110 days.
Loss of smell reduces the quality of life and increases life-threatening situations, including food spoilage, gas leaks, and smoke from fires. Western medical treatment of olfactory dysfunction typically includes steroids, nasal spray, surgical treatment, and olfactory training, none of which are particularly effective, and all of which come with adverse side effects.
Acupuncture for Loss of Smell
Researchers have found that needle stimulation transmits directly to the brain, activating the central nervous system while promoting anti-inflammatory and immunomodulatory mechanisms. In addition, investigators evaluated two cases of post-Covid loss of smell treated with traditional acupuncture.
Loss of Smell Case 1
A 53-year-old woman spent 14 days in the hospital in May 2021 receiving treatment for Covid-19. After discharge, the following symptoms remained: fatigue, olfactory dysfunction, taste dysfunction, insomnia, poor concentration, cough, shortness of breath with physical exertion, and hair loss.
A venous olfactory test determined that she had no sense of smell. The test measures olfactory mucosal dysfunction by injecting prosultiamine into a vein for 20 seconds. Technicians chart the time from injection until the scent is perceived and until the smell disappears. Non-response to the alinamin test suggests a severe olfactory dysfunction involving the olfactory mucosa. This situation was the case for the patient in Case 1.
Case 1 Acupuncture Treatment
Providers performed acupuncture in October 2021, approximately five months after the diagnosis of Covid-19. They selected the following acupoints: LI20, HT7, SP9, BL10, BL14, BL15, KD3, PC6, PC7, GB20, LV3, CV7, GV12, and GV20.
Acupuncturists stimulated the needles, eliciting “de qi” (an achy sensation referred to as acupuncture resonance), and retained them for 20 minutes. De qi is a unique sensation the patient, and the acupuncturist feels during acupuncture. Obtaining acupuncture resonance is directly correlated to the effectiveness of a given treatment.
Treatment Response
Using the Numeric Rating Scale (NRS), investigators measured improvements with loss of smell. The NRS is an evaluation method that expresses subjective sensations, such as pain, stress, and daily life obstacles, as an objective numerical value. For example, “If the ability to smell post-Covid was 0 out of 10, how much is it now?”
Researchers asked patients to express their subjective symptoms on an 11-point scale from 0 to 10. Following the first session, the patient in Case 1 became aware of the smell of coffee. The NRS score decreased from 10 to 6 immediately after her acupuncture session. Similarly, she also felt less tired. After six sessions, the NRS score initially dropped to 7. Her sense of smell was improving.
Loss of Smell Case 2
A 38-year-old man had Covid in May 2021 and was hospitalized for eight days, receiving oxygen and other treatment. The following symptoms remained after discharge: fatigue, olfactory dysfunction, insomnia, poor concentration, racing heart, fatigue after physical exertion, and heaviness in the head.
Case 2 Acupuncture Treatment
In December 2021 (approximately seven months after the diagnosis of COVID-19), providers began acupuncture treatment to address systemic symptoms and olfactory dysfunction. The acupuncture points, needles, insertion depth, and stimulation method were the same as those in Case 1.
During the first acupuncture treatment, the patient became aware of the smell of rubbing alcohol in the room. The improvement of smell lasted for three days. After the second and third acupuncture sessions, there was a rapid reduction in symptoms (NRS score, 0) that lasted for three days. However, each additional treatment prolonged the benefits. Finally, after eight sessions, the patient fully recovered his sense of smell.
Discussion
The cases described in this loss of smell study demonstrate that acupuncture positively affects post-Covid olfactory dysfunction. The key acupoint for this treatment is LI20, located in the trigeminal nerve region (second branch). LI20 transmits perception to the brain, promoting nerves of the second branch (maxillary nerve) to mix with the sympathetic and parasympathetic nerves, which impact the nasal cavity.
Previous acupuncture research on allergic rhinitis suggests that LI20 may modulate anti-inflammatory effects, including neural pathways. Furthermore, LI20 involves the down-regulation of cytokines and improved nasal ventilation from sympathetic nerve dominance.
The mechanism for healing loss of smell may involve acupuncture’s anti-inflammatory and nerve remediation effects. Moreover, a previous study of olfactory abnormalities after upper respiratory tract infection considered that acupuncture with LI20 may positively affect the cognitive processing of odors. This same potential may work when treating olfactory dysfunction in post-Covid cases.
Variation in Outcomes
In case 2, the patient’s loss of smell ultimately improved (NRS score of 0). Case 1 did not get complete healing – their NRS score was 7. Case 2 had a higher treatment frequency with LI20. Additionally, Case 1 may have had more damage to the olfactory mucosa cells.
The researchers believe that Covid-19 may cause damage to the nasal mucosa via inflammation. Furthermore, experiments with hamsters reveal the shedding of the olfactory epithelium, which contains olfactory receptors, early after infection. The olfactory epithelium generally regenerates and returns to standard thickness after injury. However, in the case of Covid infections, some of the epithelium remains damaged.
This information led the investigators to speculate that the level of damage to the olfactory mucosa in case 1 may have been stronger than in case 2. They hypothesized that the patient may have obtained additional symptom relief with additional acupuncture treatments.
Conclusion
The researchers concluded that acupuncture treatment was an effective adjunct to modern medical treatment in treating residual loss of smell after healing from Covid-19 infection. Therefore, acupuncture is a viable option for patients resistant to current medical treatments or unable to continue treatment due to adverse side effects.
Treating Loss of Smell
We have treated many patients who lost their sense of smell following exposure to Covid-19. Some responded well and regained olfactory function, while others did not. We treat new patients once a week for four weeks and assess their progress. When a patient does not respond, we stop treatment.
Our success rate for improving loss of smell is around 70 percent. Based on this experience, we encourage patients with loss of smell (and taste) to try acupuncture.
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Reference
Case Report: Acupuncture is an effective treatment for olfactory dysfunction post-COVID-19. Front. Neurol., 23 August 2022 Sec. Experimental Therapeutics
https://doi.org/10.3389/fneur.2022.916944
Focus keyphrase: Loss of Smell
Photo by Oleksandr Pidvalnyi: https://www.pexels.com/photo/woman-sniffing-flower-321581/
