Differential Diagnosis for Unilateral Sore Throat
Single Most Likely Diagnosis
- Viral Pharyngitis: This is the most common cause of a sore throat and can present unilaterally. The absence of other symptoms and a slightly red throat without lesions supports this diagnosis. Viral pharyngitis is often self-limiting and can last up to 2 weeks.
Other Likely Diagnoses
- Bacterial Pharyngitis (Streptococcal): Although less common than viral pharyngitis, streptococcal pharyngitis can cause a unilateral sore throat. However, it typically presents with more severe symptoms, such as fever, swollen lymph nodes, and a more pronounced throat redness, which are not mentioned in this case.
- Tonsillitis: Inflammation of the tonsils can cause a sore throat, which might be perceived as unilateral if one tonsil is more affected than the other. The absence of noted abnormalities on exam makes this less likely but still possible.
- Mucositis or Irritation: Local irritation from a variety of sources (e.g., postnasal drip, acid reflux, or an allergic reaction) could cause a unilateral sore throat. The lack of other symptoms makes this a plausible explanation.
Do Not Miss Diagnoses
- Lymphoma or Other Malignancies: Although rare, malignancies can present with a sore throat as an initial symptom. It's crucial to consider this in the differential diagnosis, especially if the sore throat persists beyond the expected duration of common causes.
- Peritonsillar Abscess: This is a serious complication of tonsillitis that can present with a severe, unilateral sore throat. The absence of fever, difficulty swallowing, or a noticeable collection on exam makes this less likely, but it should not be overlooked.
- Epiglottitis: Inflammation of the epiglottis can cause a severe sore throat and is a medical emergency due to the risk of airway obstruction. The lack of symptoms such as difficulty swallowing, shortness of breath, or stridor makes this unlikely, but it must be considered.
Rare Diagnoses
- Tuberculosis (TB): TB can cause a chronic sore throat, among other symptoms. It's more common in immunocompromised individuals or those exposed to TB.
- Syphilis: Secondary syphilis can cause a sore throat, among a myriad of other symptoms. This would be an unusual presentation without other signs of syphilis.
- Lemierre's Syndrome: A rare condition characterized by a sore throat followed by neck pain and fever due to a bacterial infection, typically Fusobacterium necrophorum. It's a rare but serious condition that can lead to sepsis and thrombophlebitis.