Certain embodiments of the invention are based in part on the discovery that in subjects
afflicted with psoriasis, nucleic acid samples, for example RNA samples, readily obtained from the epidermis of skin areas that contain psoriatic lesionsprovide information regarding the disease. Accordingly, the present invention provides a non-invasive method for isolating or detecting a nucleic acid molecule from an epidermal sample of a psoriatic lesion of a human subject. The method includesapplying an adhesive kinesio tape to the psoriatic lesion of the subject in a manner sufficient to isolate an epidermal sample adhering to the adhesive kinesio tape. The epidermal sample includes a nucleic acid molecule that is then isolated and/or detected directly. The method of kinesio tape stripping psoriatic lesions can be used, for example, to monitor the responsiveness of a psoriasis patient to treatment. Furthermore, the method can be used to identify genes that are predictive of response to therapy.