My husband is experiencing itchy insect bite . the following also describe him: skin redness or irritation and skin swelling. what should he do?

Insect bite: Try some over the counter anti itch cream. Even baking soda with water paste would work.

Warm compresses: Minor insect bites will usually resolve by themselves. Itching is relieved with an antihistamine such as benadryl (diphenhydramine). If after 2 days the redness or swelling increases, or if fever, or if any red streaks appear, that can be a sign of infection, and should be evaluated by your doctor right away.