Twenty-five psoriatic subjects, 15 males and 10 females, selected because of current active eruption and/or strong past history of Koebner phenomenon, were studied daily for 14 consecutive days and reobserved at 21 days. Sixteen separate test sites were utilized in an effort to both elicit and suppress visible lesions of psoriasis, utilizing selected methods of trauma and/or compounds with definite biologic action.
EDDY DD, ASCHHEIM E, FARBER EM. Experimental Analysis of Isomorphic (Koebner) Response in Psoriasis. Arch Dermatol. 1964;89(4):579–588. doi:10.1001/archderm.1964.01590280079015