A dry cough with a whooping sound in a 6-year-old child can sometimes be caused by whooping cough, also called pertussis, which is a bacterial infection that affects the airways. Children with this condition may have repeated coughing fits followed by a deep whooping sound while breathing in, and the cough may become worse at night or cause vomiting after coughing. However, other conditions such as viral infections, asthma, allergies, throat irritation, or airway infections can also cause a similar cough. It is important to have your child examined by a paediatrician, especially if the cough has lasted more than a few days, is worsening, or is affecting sleep, eating, or breathing. The doctor may advise medicines such as antibiotics if a bacterial infection is suspected, along with supportive care like plenty of fluids, rest, and avoiding smoke or dust exposure. Keeping your child's vaccinations up to date is also important because routine vaccines help protect against whooping cough. Seek urgent medical attention if your child develops difficulty breathing, bluish lips, high fever, dehydration, or severe, continuous coughing spells. Early diagnosis and treatment usually help reduce complications and improve recovery.