Symptoms
The most prominent symptom is violent cough with a peculiar sound, like 'whoop', when the person breathes. The initial symptoms are similar to common cold, like runny nose, mild cough, etc. After the initial days, the mild cough turns into spells of coughing. Sometimes, if the cough lasts longer, the person may even turn red or purple. It is also observed that the cough worsens at night.