You are completing an elective in the pediatric emergency department. Allison is a 4 year old girl who presents to you with a 5 day history of high fever, coughing, sneezing, and a runny nose. Her mother had taken her to a Medi-center 2 days ago and was advised that Allison likely had a viral infection, and that she should rest until she felt better. Since that visit, Allison’s mother informs you that her fever has been getting higher, and that Allison’s cough is becoming high pitched and resembles a dog barking. Allison’s mother mentions to you that Allison is looking increasingly unwell, and within the last 24 hours she has been making a funny noise when she breathes in.

General appearance: Appears unwell, occasional bark-like cough 
Vitals: HR: 132 beats/min, BP: 105/66, RR: 34/min, T: 39.5 C 
HEENT: Erythematous tonsils, normal tympanic membranes, coryza, rhinorrhea, conjunctivitis 
Neck: Tender cervical lymphadenopathy 
CVS: Normal S1, S2 
Pulmonary: Inspiratory stridor, no crepitations or wheezes 
Abdo: Soft and non-tender, no masses 
Neuro: Screening exam normal

Which of the following are on a differential diagnosis for Allison? (choose all that apply)