Immunodermatology is a medical specialty that focuses on the diagnosis and treatment of skin disorders characterized by defective responses of the body's immune system. Immunodermatology testing is essential for the correct diagnosis and treatment of many diseases affecting epithelial organs including skin, mucous membranes, gastrointestinal and respiratory tracts.Immunodermatology studies skin as an organ of immunity in health and disease. Several areas have special attention, such as photo-immunology (effects of UV light on skin defense), inflammatory diseases such as allergic contact dermatitis and atopic eczema, presumably autoimmune skin diseases such as vitiligo and psoriasis, and finally the immunology of microbial skin diseases such as retrovirus infections and leprosy. New therapies in development for the immunomodulation of common immunological skin diseases include biologicals aimed at neutralizing TNF-alfa and chemokine receptor inhibitors.Immunodermatology testing is essential for the correct diagnosis and treatment of several diseases affecting epithelial organs, especially skin and mucous membranes.