Suggest Treatment For Itching And Rashes All Over Body Due To Allergy

hi, i am 23 years old and i am suffering with severe allergy from last 6months, i have consulted a dermatologist and found no positive result. still i am facing a problem. i constantly have itching all over the body and this result in nettle rashes and inflammation.this inflamation can last for 24hrs sometimes ans in those areas my muscles feel very painfull. i was medicated with Elina and Allenil. i am afraid that it may be a major cause like Anaphylaxis. can u please suggest me anything