What is physical urticaria?

Urticaria induced by physical influences, take 5 mins to develop lasts 15-30 mins Cause unknown, dermographism [skin stroking], cholinergic [sweating], cold urticaria [affects skin warming up in reductions of temperature, advise to not subject to wind and swim alone] Contact urticaria [absorption of substance, allergic or not, papules in area [IgE Abs react to chemicals flour, cosmetics, textiles, latex, rubber, saliva, meat, fish and vegetables cause contact urticaria, dexa, salic, balsam of peru localized heat urticaria, aquagenic, solar, vibratory, delayed pressure (less common)