In its acute form this constitutes the most ordinary sore throat, and occurs either from "cold" especially at seasons of the year when sudden changes of temperature are prevalent, or as a local symptom of a general disease such as measles, scarlet fever, small pox. It may be said regarding scarlet fever, small pox, and diphtheria that the throat affection in them begins with an acute catarrh, but that, especially in scarlet fever and diphtheria, it nearly always goes on to phlegmonous inflammation. In the simple acute catarrh there is redness and swelling of the mucous membrane with a mucous exudation which covers the surface and may have a tough consistence. Sometimes vesicles form on the mucous membrane.

Chronic catarrh very frequently follows on the acute form, especially when there have been repeated attacks. The conditions are somewhat different in different cases, and rather complicated classifications have been introduced. As in other chronic inflammations there is here, for the most part, thickening of the mucous membrane, but in some cases the mucous membrane is indurated and atrophied. There may be a general hypertrophy of the superficial layers of the mucous membrane, and, as the blood-vessels remain congested, it is rather a succulent swelling. This constitutes what is called the Relaxed throat. The appearances are most pronounced in the case of the uvula, which becomes elongated, sometimes to a very marked extent. At other times the swelling is not so uniform, but with some general thickening there is an occasional localized prominence causing the mucous membrane to assume a granular appearance, hence the term Granular pharyngitis. This forms occurs mostly among clergymen, singers, actors, and others whose occupation requires them to use their voices for prolonged periods with a loud tone.