Bilateral infection of submental, submandibular, and sublingual spaces
Cellulitis without clear fluctuance/abscess should heighten suspicion
85% of cases arise from an odontogenic source, usually periapical abscesses of mandibular molars
Source of infection often polymicrobial, most commonly Strep, Staphylococcus, and Bacteroides species
Patients usually 20-60yr; male predominance 
Often there is no lymphatic involvement and no abscess formation but infection rapidly spreads bilaterally
Ludwig's angina
Streptococcal pharyngitis 
CMV esophagitis
Neisseria gonorrhoeae
Peritonsillar cellulitis
Diphtheria 
Esophageal candidiasis
Bacterial Tracheitis