Talk to Allergy Specialist on I Have Itching On My Whole Body

Dear Doctors, I am suffering from itching and heat on my whole body since 2 and a half years. I had got covid during that period I ate alot of hot stuff like nuts and eggs etc. Now when ever i eat nuts/dates/fish/eggs or drink tea or even take bath with lukewarm water it get worse. I have visited a skin specialist he has recomended me tablets of Zyrtec and Ventek for a month and ask for a test of serum IGE. The reports suggests that levels are normal .ie. 51. The doctor has told to continue the medicines for one month. My question is that when no allergy is found in the test then how i am feeling well after taking anti allergy medicines prescribed above? and when i will stop taking medicines after 1 month will the symptoms like itching and hives will come again? do the medicines are suppressing the symptoms or curing the disease?Please also suggest an alternate of ventek because i got motion after taking this medicine