Girls, my friend's daughter has problems, she's 5 years old, she has…

Girls, my friend's daughter has problems, she's 5 years old, she has severe rashes on her skin, all the tests were good, they prescribed them treatment for allergies and diet, it went down a little, it lasted two weeks and again started, gives off from allergies, something is smeared, nothing helps, doctors wave their hands. Maybe someone encountered, what can you still do? It's sad that the girl is suffering ?