What is the treatment for Covid-induced anosmia?

From the Guidelines

The primary treatment for COVID-induced anosmia is olfactory training, which has shown benefit in improving smell function, as evidenced by a systematic review evaluating the management of postinfectious olfactory dysfunction 1. This approach involves sniffing four distinct scents (typically lemon, rose, clove, and eucalyptus) for 20 seconds each, twice daily for at least 3-6 months. Some key points to consider in the treatment of COVID-induced anosmia include:

• Olfactory training has been consistently shown to be beneficial in improving smell function, with all 11 studies evaluating this intervention demonstrating a benefit 1.
• The use of intranasal corticosteroids, such as mometasone furoate, has been studied, but a low-quality RCT found no difference in rates of olfactory recovery or duration of anosmia/hyposmia when compared to olfactory training alone 1.
• Other therapies, such as insulin fast-dissolving film for intranasal delivery, have shown promise in small studies, with one RCT demonstrating significantly higher olfactory detection scores with intervention 1.
• The mechanism of COVID-induced anosmia involves direct damage to supporting cells in the olfactory epithelium, which explains why most cases resolve with time as these supporting cells regenerate. It is essential to note that the evidence for these treatments is not yet robust, and more research is needed to fully understand the effectiveness of these interventions. However, based on the current evidence, olfactory training remains the primary recommended treatment for COVID-induced anosmia, with other therapies considered on a case-by-case basis.

From the Research

Treatment Options for Covid-Induced Anosmia

• Olfactory training is a recommended treatment for post-COVID-19 olfactory dysfunction, as it has the greatest degree of supporting evidence 2.
• Intranasal corticosteroids and oral corticosteroids may alleviate symptoms, although limited clinical trials and prospective controlled trials are available to support their use 2, 3.
• A combination of systemic corticosteroids and intranasal corticosteroid/mucolytic/decongestant may be effective in improving olfactory function, as shown in a multicentre randomised case-control study 3, 4, 5.
• Palmitoylethanolamide plus luteolin has been evaluated as a potential treatment, but the certainty of evidence is very low due to the small sample size of the study 4.
• Structured olfactory training with essential oils is the preferred treatment for parosmia, a common qualitative olfactory dysfunction associated with COVID-19 6.
• Nasal corticosteroids may accelerate recovery of olfactory function, but the evidence is limited 6.

Key Considerations

• Most cases of post-COVID-19 olfactory dysfunction resolve spontaneously within 2 weeks of symptom onset, but patients with persistent symptoms require medical management 2.
• The presence of parosmia predicts persistent quantitative olfactory dysfunction and may require specialized treatment 6.
• Patients should be prepared for the possibility that symptoms may persist for years and should be guided to resources for coping with their psychosocial burden 6.