Biphasic course
Early prodromal period often appears as an flu-like illness
Fever, dry cough, myalgia, malaise
Transient clinical improvement followed by rapid decline
Severe respiratory distress with symptoms consisting of:
Hypoxia, tachypnea, cyanosis
Severe dyspnea, chest pain
Shock
Mediastinitis
Hypoxia, tachypnea, cyanosis
Severe dyspnea, chest pain
Shock
Mediastinitis
The disease will start as an area of erythema and edema and progress to a vesicle which ruptures forming a central black eschar which eventually falls off
Total course of lesion evolution occurs over 1 week
Small minority of untreated patients develop rapidly fatal bacteremia 
Over the course of 7 days, nonspecific abdominal pain, nausea and vomiting with progress to severe abdominal pain, bloody emesis and diarrhea (usually bloody)
May present as oropharyngeal ulcers with dysphagia
Anthrax
Ecthyma gangrenosum
Plague
Rat-bite fever 
Rubella
Ulceroglandular tularemia
Varicella
Metal fume fever