Hi, After reading your query I can make out that you are suffering from urticaria. Urticaria is a common condition caused by bursting of allergy producing cells known as mast cells due to certain aggravating factors present in the environment. As the chemical inside them is released it produces a rash which you have mentioned. There can be multiple factors producing this condition which are included in day to day life and some times it is really difficult to find one exact cause. So it is better to stay away from the offending factors. The long term effective treatment for this is by oral anti histamine like loratadine under medical advise. take care.