The causes for psoriasis may be multi-factorial.  However, most naturopathic physicians believe there is a strong connection between skin conditions and the digestive system.  The "gold standard" for testing food sensitivities is called the elimination and rotation diet.  A food is eliminated for at least 5-6 weeks, and symptoms are monitored.  The food is reintroduced and symptoms are monitored.  Most allergists will test food allergies with a "scratch test" whereby a small amount of the substance is scratched into the skin and the skin reaction is monitored.  Your dermatologist may/may not provide this test.  Blood tests are also available from a variety of laboratories.  Food sensitivities (vs. allergies)  may not produce a measurable reaction in blood tests, so other types of testing may be needed to identify sensitivities.  Some psoriasis may also benefit from light  therapy and certain supplements. http://www.countrydoc.com

Dr. Karen Benton, Naturopathic Physician