What does the presence of vesicles or ulcers in pharyngitis suggest as the etiology?

The presence of vesicles or ulcers in pharyngitis is highly suggestive of herpes simplex virus (HSV) infection as the underlying cause. Herpes simplex virus typically manifests with oral lesions, which can include painful vesicles that eventually ulcerate. In the context of pharyngitis, these vesicular lesions can be found in the posterior oropharynx, contributing to significant discomfort and difficulty swallowing.

While other viral causes, such as adenovirus, can lead to pharyngitis, they usually present with a more typical clinical picture of redness and swelling rather than vesicles or ulcers. Bacterial infections, such as streptococcal pharyngitis, also do not present with vesicles or ulcers, but rather with more classic signs like tonsillar enlargement and the presence of purulent exudate.

Herpes simplex virus is distinct in its presentation within the realm of viral infections affecting the throat. Therefore, vesicular or ulcerative changes in the context of pharyngitis strongly point towards herpes simplex virus as the etiology.