Can Steroid Be Taken For Heat Rash On Body?

I am going on holiday soon and always suffer from heat rash, I have tried take anti histamine tablets and using a lotion but none of this works. Last year when i went to Cyprus the chemist gave me a course of tablets and it vanished staright away. I've been reading up on the internet and there is a steroid tablet that can be taken but only if perscribed by my doctor, do you think I will be able to get this as a lot of people have said their doctors would not perscribe it?