My 4yo has a dry hacking cough. no fever, rash etc still eating and seems himself. but has long coughing fits intermittantly through the day and night?

Probably viral : Probably a viral illness and may settle with time but seek urgent attention if worsening breathing or persistent vomiting. May also need gp to check for other underlying conditions such as asthma if cough persistent.

Cough: There re several questions around the issue. How long the cough has bene there, any wheezing, is it barking cough, any history of asthma or hay fevers, any runny nose or upper rest symptoms. I think a good history and examination by your gp will be required. It cough be a viral cough, croup or a allergic cause. Please see your GP for review

Infection Vs Asthma: There are a number of possibilities. Has this been going on a long time? Some viral illnesses leave people with a persistent cough that can last for many weeks. Other infections like pertussis can cause a '100 day cough', also known as whooping cough. Asthma can also present as cough (typically night time cough). A history and exam from your Dr will probably answer the question.

Cough: There can be different reasons for dry hacking cough starting form asthma, viral infection, post viral infection cough, bacterial infections like pertusis ( whooping cough ) or allergy . Please do consult your doctor for examination to confirm the diagnosis .

Possibly Croup: Croup is a common respiratory problem in young children. It tends to occur in the fall and winter. Its main symptom is a harsh, barking cough. Croup causes swelling and narrowing in the voice box, windpipe, and breathing tubes that lead to the lungs. An attack of croup can be scary, but it is rarely serious. Children usually get better in several days with rest and care at home.