What could be the reason for the red and purple itchy spots on the skin?

Hi doctor,

I just moved from one country to another and have been eating many unusual foods. I am a vegan but have eaten meat and transferred from being primarily vegetarian due to hidden meat and animal products in food. I include this information as I wonder if this results from food. I get a lot of mosquito bites and am constantly itchy. However, some unique purple and red spots are clustered only inside my arms and biceps. One is itchy regularly, while the other is just there. It might be from my workout routine, but I have lifted much heavier weights regularly weeks earlier. I have never had anything like this.

I have had contact dermatitis in the past, and my contact dermatitis does not look like this.

Thank you.