Small fiber neuropathy as a complication of SARS-CoV-2 vaccinations

Generally, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinations are not free of side effects. A rarely reported adverse reaction to SARS-CoV-2 vaccinations is small fiber neuropathy (SFN). Here, we present three patients with SFN after the second dose of messenger ribonucleic acid-based SARS-CoV-2 vaccines. Data for this study were collected via the self-made platform "Pubbly" for reporting side effects of SARS-CoV-2 vaccinations. Three patients with post-SARS-CoV-2 vaccination SFN were identified: a 40 yo Caucasian female (patient 1), a 52 yo Caucasian female (patient 2), and a 32 yo Caucasian female (patient 3). Patient 1 complained about fatigue, dizziness, flushing, palpitations, diarrhea, muscle weakness, and gait disturbance 10 days after the second Pfizer jab. Patient 2 reported dizziness, balance problems, brain fog, palpitations, dysphagia, and sleep problems. Patient 3 complained about profound fatigue, brain fog, vertigo, pre-syncopal sensations, hair loss, chest pain, dyspnea, palpitations, paresthesias, irregular menstrual cycles, muscle weakness, and hives 1 day after the second Moderna dose. All three patients underwent skin biopsy upon which SFN was diagnosed. Patient 1 profited from immunoglobulins, but patient 2 did not require any treatment. Symptoms in patient 3 resolved upon symptomatic treatment. Despite treatment, patient 1 did not completely recover. SFN can be a rare side effect of SARS-CoV-2 vaccinations. Post-SARS-CoV-2 vaccination SFN can be mild or severe and may or may not require treatment. Post-SARS-CoV-2 vaccination SFN is most likely immune-mediated as it responds to intravenous immunoglobulins.