Hive or bite? itchy red lesions on arms, face or chest seem to have center, but only occur on or after weekend (at home), so maybe food allergy?

More likely bites: If you have pets at home, insect bites would be my bet. If you live in housing with a lot of cockroach issues, roach bites do happen.

Bites: Hive like bumps with centers are called "papular urticaria" and are typically caused by insect bites. Crops of three are often from fleas - do you have any pets? Bed bugs and other insects that are in your home can all be culprits.