Did you try calamine lotion? Probably you are having a solar urticaria.Is it present mostly in the exposed areas of your body? . The most common cause is the exposure to ultraviolet radiation..A photo patch test or a photo test is done to identify solar urticaria.Anti histamine/anti allergic drugs are the main medical treatment.There is another form of treatment called desensitization.This form of treatment is meant to reduce the intensity or altogether eliminate the allergic reactions people have by gradually increasing exposure to the form of radiation that brings about the reaction.In the case of solar urticaria, phototherapy and photochemotherapy are the two major desensitization treatments.Sometimes immunosuppressive drugs such as prednisolone and ciclosporin is prescribed if the patient is suffering from an intense form of solar urticaria. However, the side effects of these medicines can be severe which is why they are reserved for the most extreme of cases.Then there is another method called plasmapheresis in which the blood is cleared of the factors that cause urticaria.But this is in the development stage.So you can discuss this with your local doctor and also try calamine lotion over the lesions..