Causes
The most common cause is viral infection and includes adenovirus, rhinovirus, influenza, coronavirus, and respiratory syncytial virus. It can also be caused by Epstein-Barr virus, herpes simplex virus, cytomegalovirus, or HIV. The second most common cause is bacterial infection of which the predominant is Group A β-hemolytic streptococcus (GABHS), which causes strep throat. Less common bacterial causes include: Staphylococcus aureus (including methicillin resistant Staphylococcus aureus or MRSA ),Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae, pertussis, Fusobacterium, diphtheria, syphilis, and gonorrhea. A coexisting GABHS and influenza A virus pharyngotonsillitis has been reported.
Anaerobic bacteria have been implicated in tonsillitis and a possible role in the acute inflammatory process is supported by several clinical and scientific observations.
Under normal circumstances, as viruses and bacteria enter the body through the nose and mouth, they are filtered in the tonsils. Within the tonsils, white blood cells of the immune system destroy the viruses or bacteria by producing inflammatory cytokines like Phospholipase A2, which also lead to fever. The infection may also be present in the throat and surrounding areas, causing inflammation of the pharynx.
Sometimes, tonsillitis is caused by an infection of spirochaeta and treponema, in this case called Vincent's angina or Plaut-Vincent angina.
Read more about this topic: Tonsillitis