Final answer:
Sore throat is an infection of the pharynx that causes erythematous and swollen tissue, along with possible inflammatory exudates, vesicles, and mucosal ulceration or nasopharyngeal lymphoid hyperplasia.
Step-by-step explanation:
The infection of the pharynx described in the question is commonly known as sore throat. The presentation of sore throat includes erythematous (red) and swollen tissue in the pharynx, and it may be accompanied by inflammatory exudates, vesicles, mucosal ulceration, or nasopharyngeal lymphoid hyperplasia. This condition is often caused by a bacterial infection, most commonly Streptococcus pyogenes, which is known as strep throat.