Urticarial rash due to Allergy?

A gentleman came to see me this evening with itchy multiple red patches on his trunk, upper and lower limbs. He remembered going to a Christmas event and putting on an old jacket (belonging to his dad). He thinks he is allergic to the dust mites or fungal spores on the jacket, or is it the food served at the dinner?

He was given an injection of Anti-Histaminics to relieve his symptoms and given some new generation oral histaminics to take in the day time and a drowsy 1st generation Anti-histaminic for the severe itch at night. If his symptoms are severe, he may benefit from some corticosteroids orally or by injection (However, care needs to be taken as these should be given to athletes in emergencies only as they are on the Prohibited list and require TUE).