Q fever
Tuberculosis
Pneumonia
Viral pharyngitis
Mononucleosis-like illnesses (EBV, CMV, acute HIV)
Peritonsillar abscess vs. Retropharyngeal abscess vs. Ludwig's angina
Mumps
Sjögren<unk> 
Heerfordt's<unk>  (small percentage of sarcoidosis)
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<unk> 
Patients with peritonsillar abscess have a 20% incidence of mononucleosis 
Herpangina
Hand-foot-and-mouth disease
Stevens-Johnson<unk> 
Pemphigus
Angioedema
Deep neck space infection
Retropharyngeal abscess
Ludwig's angina
Parapharyngeal space infection
Peritonsillar Abscess (PTA)
Epiglottitis
Kawasaki disease
Penetrating injury
Caustic ingestion<unk> 
Peritonsillar cellulitis
Lymphoma
Internal carotid artery aneurysm
Oral Thrush
Parotitis
Post-tonsillectomy hemorrhage
Vincent's angina
Acute necrotizing ulcerative gingivitis
Retropharyngeal abscess
Ludwig's angina
Parapharyngeal space infection
Lemierre's syndrome
Q fever
AIDS fever of unknown origin
Tuberculosis
Pertussis
Pneumonia
Diphtheria
Viral pharyngitis