thanks for your query.
i think your son had ingested some food that caused food poisoning
along with some allergic reaction
he needs to have ofloxacin-ornidazole
combination twice daily for seven days along with domperidone
tablets if there is persisting vomiting. Along with this he needs to have plenty of ORS to be taken orally.
Try allegra 150 mg once daily for 5-7 days and if even after 2 days itching is not improving then he should take desloratadine 5 mg daily or one decadron injection.
i think after all these your son will be quite ok.