Variations in the appearance of posterior pharyngeal wall follicles in individuals with viral upper respiratory infections according to the virus and the stage of infection: A case series.

From August 2021 to January 2022, four patients presented to our hospital with short-term throat pain. The cause could not be determined from the symptoms. These included a 24-year-old vaccinated man with SARS-CoV-2 infection, presumably the Delta variant (B.1.617.2) (Case 1), a 31-year-old woman with rhinovirus/enterovirus infection (confirmed on a BioFire Respiratory 2.1 Panel) (Case 2), a 26-year-old non-vaccinated man with SARS-CoV-2 infection, confirmed as the Omicron variant (B.1.1.529) (Case 3), and a 39-year-old vaccinated woman with SARS-CoV-2 infection, presumably the Omicron variant (Case 4). The follicles on the patients’ posterior pharyngeal walls changed size/form over the infection course (Figure. 1 ). In Cases 1 and 3, the follicles persisted after the throat pain resolved and SARS-CoV-2 RNA was undetectable (Fig. 1B and 1D) and disappeared by the 2-month follow-up.

Figure 1

Photographs of follicles on the posterior wall of the pharynx in patients with upper respiratory infections.(A, B) Pharyngeal follicles (black arrows) in Case 1, a 24-year-old vaccinated male with breakthrough SARS-CoV-2 infection, 4 days (A) and 13 days (B) after symptom onset. The follicles in (B) appear more reddish, enlarged, flat, oval, and opaque than those in (A). (C) Pharyngeal follicles in Case 2, a 31-year-old female with rhinovirus/enterovirus infection, 3 days after symptom onset. The follicles are elevated and round and are larger and paler than those seen in Case 1. (D) Pharyngeal follicles in an unvaccinated 26-year-old male with SARS-CoV-2 (Omicron variant) infection, 10 days after symptom onset. The follicles are oval and red. (E, F) Pharyngeal follicles in Case 4, a 39-year-old vaccinated woman with breakthrough SARS-CoV-2 infection, 5 days (E) and 8 days (F) after symptom onset. Some follicles are enlarged, flat, and opaque.

Some viral upper respiratory infections cause lymphoid follicle development on the posterior pharyngeal wall (Akihiko and Shigeyuki, 2011; Sakuma, 2008; Takahashi, 2022). The pharynx is a site of viral entry, replication, and transmission. The pathogen and infection stage can affect the follicle form; follicle growth or atrophy may indicate viral proliferation or shedding, respectively (Akihiko and Shigeyuki, 2011; Huang et al., 2021). Pharyngeal wall follicle development in COVID-19 patients without throat pain remains unknown and requires further investigations.

Declaration of Competing Interest

None declared.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Consent for publication

The study patients provided written informed consent for publication of their case details and the accompanying images.

Declaration of interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.