Hello, Well an itchy rash is a very vague complaint. The complete diagnosis depends on the clinical examination. But as you said that you have seen a dermatologist you must have been given some diagnosis, naming it would have informed more. Otherwise this itch could be due to certain eczematous reaction which is a broad term for all the itchy complaint and may include contact dermatitis or a simple plain heat rash (milia rubra) as well. Instead of worrying about the cause, which in most of such causes remain unknown you can try other treatment options available in alternative medicines. I can assure you that itches like this are very aptly cured under homoeopathy. Regards, Dr. Raavi