What is that smell?

Research studies examining impaired or heightened sense of smell have been focused primarily on patients suffering from neurological disorders, like Alzheimer’s and Parkinson’s disease. Only recently, have researchers begun to investigate the connection between olfactory disorders and autoimmune diseases. 

And, while there have been many anecdotal reports from Lyme disease patients complaining about their sensitivity to smells, there has never been a study examining the association between Lyme disease and hyperosmia — until now.

After administering questionnaires to 16 serologically positive Lyme disease patients and 18 control subjects, researchers found that 50% of the patients with Lyme disease suffered from hyperosmia, versus none of the control subjects. The findings were published in the Arquivos de Neuro-Psiquiatria Journal. 

“The high prevalence of this olfactory disorder found in our study suggests the need for further studies of olfactory function in this disease,” concludes the authors. “It would also be of interest to carry out longitudinal studies to evaluate the response of hyperosmia to antibiotic pharmacotherapy.”

In my own unofficial Facebook poll, 86% of the 22 responders reported experiencing difficulties with smell after their Lyme disease diagnosis.

In contrast, a decreased sense of smell, hyposmia, has been described in patients diagnosed with Fibromyalgia and COVID-`9. Fibromyalgia patients had “significantly lower thresholds of smell compared to healthy controls.” The investigators did not address hyperosmia.

Hyposmia was observed in 42 % patients with Fibromyalgia compared to 15 % of patients with systemic sclerosis and 4% of the healthy controls. “Our findings suggest that there is a decrease in the sense of smell both in Fibromyalgia and systemic sclerosis patients compared with healthy controls.”

Although having an altered ability to smell, whether lessened or heightened, may seem insignificant, these studies are a reminder of how vast the presentations can be in Lyme disease patients. And, how much more we still have to learn about this disease.