Could someone help me?

First the mom fell ill with coughs. Then later all three kids came down with itches. Naturally I gave them the right medicine. Yet not even an hour later the boy comes down with the same itches. I gave him the medicine again but I have a feeling it might come back.

So, in order to save $175 (they need to stock up on their groceries so I can't afford the doctor's visit), I thought I should ask here first. Could it be a recurring illness and should I take pre-emptive action and buy the medicine for persistent illnesses?