My husband has a very itchy fine red dot rash over his trunk, legs, arms. He has had it for the last 3 days with the last 2 being more itchy and uncomfortable. He was out pulling weeds in the yard but was covered with long sleeves, gloves, pants. He took OTC Benadryl with only fair relief, is worse as soon as med wears off. No fever or pain, very itchy. Wondering what it could be and any suggestions on how to treat it?