Sore throat, or pharyngitis, is a common symptom of infection with SARS-CoV-2, the virus responsible for COVID-19. As the virus has evolved through different variants, throat symptoms have often become a more prominent and sometimes severe complaint. This focus on the upper respiratory tract means the pharynx and larynx are frequently involved early in the infection process. Understanding what COVID-19 does to the throat, both visibly and symptomatically, provides valuable insight into the body’s response to the virus.
How COVID-19 Affects the Visual Appearance of the Throat
The visual signs of a COVID-19 throat infection typically reflect generalized inflammation rather than specific, localized lesions. A physical examination commonly reveals mild to moderate redness, known as erythema, across the pharyngeal wall and sometimes the tonsils. This is a non-specific sign of viral pharyngitis, indicating a localized immune reaction. The tonsils and surrounding tissues may appear slightly swollen, though often not to the degree seen in bacterial infections.
A distinguishing feature is the general absence of tonsillar exudate, which are the white patches or streaks of pus. While some patients, particularly those infected with certain variants like Omicron, have presented with small, closely aggregated white spots on the posterior pharynx, this is not the typical finding. The visual presentation can also be highly variable, as some individuals report significant throat pain without any noticeable visual changes upon examination.
Associated Subjective Throat and Laryngeal Symptoms
The feeling of a COVID-19 throat infection often begins with a sensation of dryness, scratchiness, or a persistent tickle. Patients frequently report pain that ranges from mild soreness to an intense discomfort, sometimes described as feeling like “razor blades” when swallowing. This pain is often one of the earliest symptoms to appear in the course of the illness.
The virus often affects the larynx, or voice box, leading to associated laryngeal symptoms. Hoarseness, a tired voice, or even a temporary loss of voice (laryngitis) are common complaints. This inflammation of the vocal cords can also cause a constant need to clear the throat and may be aggravated by the persistent cough that often accompanies the infection.
Understanding the Biological Mechanism of Throat Involvement
SARS-CoV-2 targets the throat because of the presence of the Angiotensin-Converting Enzyme 2 (ACE2) receptor. This protein is abundantly expressed on the surface of epithelial cells lining the upper respiratory tract, including the pharynx and larynx. The virus’s spike protein binds to the ACE2 receptor, allowing the virus to enter the cell and begin replication.
Once inside the cells of the throat lining, the virus’s replication triggers a localized, rapid immune response. This response is responsible for generating the inflammation and redness observed in the throat. The resulting cellular damage and subsequent immune reaction are the direct cause of the pain and swelling, particularly pronounced with newer variants that replicate efficiently in pharyngeal tissues.
Key Differences From Strep Throat and Common Colds
Distinguishing a COVID-19 sore throat from other common infections like Strep throat relies on a constellation of symptoms. Strep throat, caused by Streptococcus bacteria, typically presents with a sudden, severe sore throat, often accompanied by a high fever. The most significant visual difference is the presence of white patches or pus on the tonsils, which is a hallmark of bacterial pharyngitis and rare in COVID-19. Strep throat usually does not involve respiratory symptoms like a cough or runny nose, which are frequently seen with COVID-19.
A common cold, caused by numerous other viruses, often starts with a scratchy throat but quickly shifts to heavy nasal congestion, sneezing, and a runny nose. While COVID-19 can also cause congestion, it frequently presents with more pronounced systemic symptoms such as severe fatigue, body aches, and fever alongside the throat pain. A loss of taste or smell is a key differentiator for COVID-19, a symptom not typically associated with either Strep throat or the common cold. Because of the significant overlap in symptoms, laboratory testing is the only reliable way to confirm the cause of a sore throat.