Which phase of pertussis is characterized by symptoms resembling an upper respiratory infection?

The correct answer is the catarrhal stage. This early phase of pertussis is characterized by symptoms that closely resemble those of a typical upper respiratory tract infection. During the catarrhal stage, a patient may experience symptoms like a mild cough, runny nose, low-grade fever, and conjunctivitis. These initial symptoms usually last about one to two weeks before progressing to the more severe paroxysmal stage, where the classic whooping cough occurs.

Understanding the catarrhal stage is crucial since the symptoms can easily be mistaken for a common cold, which may delay appropriate diagnosis and management of pertussis. Early recognition of these symptoms is important because treatment with antibiotics during this stage can reduce the severity and duration of the illness and prevent the spread of the infection to others.