No one is making any conclusions.
The reason people use MedHelp is to get some idea what may be the problem and whether they should seek medical attention. This is because a lot of people cannot afford to pay to see a doctor.
I have myself experienced a similar situation in the past where the doctor prescribed an antibiotic and a strong antihistamine. My problem was caused by an allergic reaction and an infection from a cat scratch.
There is no reason to conclude this is an allergic reaction, although it might be. Nor is there any reason to conclude this is something that could be treatede with antibiotics.
These skin problems can be due to liver disease or hepatitis.
You should not be self-treating with antihistamines. Among other things you will mask symptoms, and delay treatment for what may a life-threatening problem.
This is not a question for an internet chat board. You absolutely positively need an in-person evaluation by a physician.
If there is no fever, it is highly likely to be an allergic reaction.
A body rash with feeling unwell and feeling hot with chills can sometimes be an infection.
If you have not seen your doctor with regard to this, then it would be a good idea to see him. He may know what the problem is. He may prescribe an antihistamine medication for you.
Think about when the rash started to appear. Was there any change in soaps, detergents, new foods, cheeses, herbs, new make-up, perfume, any type of spray, contact with any weeds or plants, oily rags, chemicals, animals, sun exposure, swimming, the list is endless.
Keep a written record to identify when the rash flares up. As the rash "comes and goes" there is clearly a trigger - this can be food, drink, or something that you are coming into contact with. Keeping a diary may help you to identify the culprit so that you can avoid it.
You can purchase antihistamines from the pharmacy, but I would advise a visit to see your doctor. He can prescribe a much stronger antihistamine and if he suspects it may be caused by an infection, he would also prescribe an antibiotic.
To help to reduce the hot and burning sensations apply calomine lotion or a calomine based cream. You can purchase this from the pharmacy.
Take cool showers to cool down the body and don't use any soaps, shower gels etc. Pat dry gently.
Let me know when you find out the cause and the doctor's diagnosis.
Best wishes.