Dear Venkata some fungi are known as highly antigenic to provoke immune system to attack mast cells to produce Urticaria one of them is Candida as this reaction is known as dermatophytid or id reaction which stop once fungus erradicated.
Id reaction, or autoeczematization, is a generalized acute cutaneous reaction to a variety of stimuli, including infectious and inflammatory skin conditions. The pruritic rash that characterizes the id reaction, which is considered immunologic in origin, has been referred to as dermatophytid ( Candida) , pediculid (sarcobtes scabii) or bacterid (H. pylori) when associated with a corresponding infectious process.