Streptococcal pharyngitis (Strep Throat)
Neisseria gonorrhoeae
Diphtheria (C. diptheriae)
Bacterial Tracheitis
Infectious mononucleosis (EBV)
Patients with peritonsillar abscess have a 20% incidence of mononucleosis 
Laryngitis
Acute Bronchitis
Rhinovirus
Coronavirus
Adenovirus
Herpesvirus
Influenza virus
Coxsackie virus
Herpangina
Hand-foot-and-mouth disease
HIV (Acute Retroviral Syndrome)
Patients with peritonsillar abscess have a 20% incidence of mononucleosis 
Herpangina
Hand-foot-and-mouth disease
Stevens-Johnson Syndrome
Pemphigus
Angioedema
Deep neck space infection
Retropharyngeal abscess<unk> 
Parapharyngeal space infection
Peritonsillar Abscess (PTA)
Epiglottitis
Kawasaki disease
Penetrating injury
Caustic ingestion
Lemierre's syndrome
Peritonsillar cellulitis
Lymphoma
Internal carotid artery aneurysm
Oral Thrush
Parotitis
Post-tonsillectomy hemorrhage
Vincent's<unk> 
Acute necrotizing ulcerative gingivitis
Retropharyngeal abscess<unk> 
Parapharyngeal space infection
Ludwig's angina
Streptococcal pharyngitis 
CMV esophagitis
Neisseria gonorrhoeae
Peritonsillar cellulitis
Diphtheria 
Esophageal candidiasis
Bacterial Tracheitis