Welcome and thanks for posting your query to HCM.
After reading your query it appears the possibility of "Urticaria" aggravated by physical factors.
Urticaria is a common condition caused by bursting of allergy
producing cells known as "mast cells". As the chemical inside them is released causes the kind of rash which you mentioned. There can be multiple factors producing this condition. In your case it appears to be due to physical factor, especially environmental inform of cold and warm weather.
For the betterment kindly follow the suggestions below:
-Most important thing to do is to avoid the abrupt change in weather from cold to hot and hot to cold. This would be the most important factor to reduce your problem.
-Apply over the counter calamine
lotion 3-4 times a day.
-You can do cold water compresses to reduce the intensity of itching.
-Do not scratch or rub the skin as it can lead to further aggravation.
-Kindly stop taking oral steroids
as self medication
as it can lead to side effects. So you can take oral anti histamine
or levocetrizine under medial advice.
Despite above measures if the problem is not getting better then it is better to consult a dermatologist
for best guidance. Hope these informations are helpful.
"Wish you good health"
Dr Sanjay Kumar Kanodia
MD (Dermatology & STDs)