The following is a summary of “Small fibre neuropathy frequently underlies the painful long-COVID syndrome,” published in the May 2024 issue of Pain by Falco et al.

In some patients, long-term pain symptoms may be due to small-fiber neuropathy, which affects nerve fibers.

Researchers started a retrospective study investigating whether small fiber neuropathy is present in patients with long-COVID experiencing pain.

They collected clinical data, quantitative sensory testing results, and skin biopsies from 26 patients diagnosed with painful long-COVID syndrome. Additionally, 100 individuals with a history of COVID-19 were examined, with 33 patients selected for experiencing painless long-COVID syndrome characterized mainly by symptoms such as brain fog and fatigue, and 30 asymptomatic post–COVID–19 controls. Demographic and clinical variables were compared among the groups.

The results showed that of 26 patients with the painful long-COVID syndrome, 12 exhibited abnormalities in skin biopsy and quantitative sensory testing consistent with small fiber neuropathy. Demographic and clinical data were consistent across patients with small fiber neuropathy, patients with painless long-COVID syndrome, and asymptomatic post–COVID–19 controls. The case-control study revealed that approximately 50% of patients with the painful long-COVID syndrome had small fiber neuropathy. The patient cohort, specifically post–COVID–19 complications, showed no correlation with demographic and COVID-19 clinical variables. About half of patients with painful long-COVID symptoms fulfilled the diagnostic criteria for small fiber neuropathy.

Investigators found that around patients with half of the long-COVID pain had small fiber neuropathy, but it wasn’t linked to factors like age or initial COVID-19 severity.

Source: journals.lww.com/pain/abstract/9900/small_fibre_neuropathy_frequently_underlies_the.593.aspx