Thank you for your query,
It seems your child is having allergic skin rash
Atarax is an oral antihistamine and it relives the itching due to the allergy.
which is a steroid, which controls allergic reaction
and to be taken for shorter periods and with food.
Calosoft is lotion contains alovera and calamine. It helps to decrease the itching and causes soothing effect.
The cause of allergy to be looked in to like any new food, duct, clothing chemical or any pet animal and avoid that if it is known.
Hope I have answered your query.