[2] Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice.

[2] Uncommon causes include other bacteria such as gonococcus, fungi, irritants such as smoke, allergies, and gastroesophageal reflux disease.

[8] Other conditions that can produce similar symptoms include epiglottitis, thyroiditis, retropharyngeal abscess, and occasionally heart disease.

[2] It is unclear whether steroids are useful in acute pharyngitis, other than possibly in severe cases, but a recent (2020) review found that when used in combination with antibiotics they moderately reduced pain and the likelihood of resolution.

Acute pharyngitis may be catarrhal, purulent, or ulcerative, depending on the causative agent and the immune capacity of the affected individual.

[19] Streptococcal pharyngitis or strep throat is caused by a group A beta-hemolytic streptococcus (GAS).

[21] Fusobacterium necrophorum is a normal inhabitant of the oropharyngeal flora and can occasionally create a peritonsillar abscess.

[22] Diphtheria is a potentially life-threatening upper respiratory infection caused by Corynebacterium diphtheriae, which has been largely eradicated in developed nations since the introduction of childhood vaccination programs, but is still reported in the Third World and increasingly in some areas in Eastern Europe.

[26] Pharyngitis may also be caused by mechanical, chemical, or thermal irritation, for example cold air or acid reflux.

[21] One point is given for each of the criteria:[21] The Infectious Disease Society of America recommends against empirical treatment and considers antibiotics only appropriate following positive testing.

[29] Testing is not needed in children under three, as both group A strep and rheumatic fever are rare, except if they have a sibling with the disease.

[37] Acute pharyngitis is the most common cause of a sore throat and, together with cough, it is diagnosed in more than 1.9 million people a year in the United States.