I was first diagnosed with poison ivy about 2 weeks ago. The first initial rash from that has started to subside. Yesterday I noticed my stomach region was starting to itch as well but no rash. Last night I woke up in the middle of the night and my stomach is covered in a red rash. It almost resembles a heat rash but it isnt going away. I also noticed a few new spots on my knee and arm that are itching and look like the poison ivy. I have not been around any poison ivy and everything in my home has been treated/washed since. I have also had diahrrea and stomach pain the past two days. I wasnt sure if this was all related or totally separate things. I was taking a 5 day dose of prednisone and my last dose was on Saturday.
From the information that you have given it seems that the two symptoms are different and due to different causes. Two weeks ago you probably had contact dermatitis to poison ivy, but the present symptoms suggest that you might be having some allergic reaction to some food products. Sometimes allergic reaction to food products can cause diarrhea, stomach pain along with hives over the body. You will need to take anti histamine tablets and apply calamine lotion over the hives. I would suggest you consume bland food for now, consume adequate amount of water to avoid deny Chat Doctor. Hope it helps,