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Your child is suffering from allergic bronchitis
.Allergy may be from outside source or from inside the body.
Please see that your child is having worm infestation like thread worm,round worm or tape worm, this may cause allergic manifestation resulting cough
cold or asthmatic attach.
Allergy causing from out side source are dust,pollen body,change of climate and some food allergy
You observe all above factors and you may find some allergy factor and avoid that factor and your child will be alright.
Go for x ray
chest,blood for tc,dc,esr etc which will give you type of infection and allergy.