What is the difference between croup and pertussis cough?

Cough types: In general, the cough of croup is usually worse at night, and resembles the bark of a seal or dog. Pertussis coughs are generally repetitive initially (frequently causing gagging and vomiting), and later by a characteristic 'whoop' at the end of a coughing episode. Croup is scary but not dangerous as pertussis is in small children.