text: If after lifting up the pencil eraser it is obvious that the skin has markedly split, then this procedure should be re-done a bit less vigorously (to at most demonstrate a minimal puckering of the skin) in an adjacent area. However, if absolutely no change is visible after having tried to induce a blister, then one should still biopsy that area in the hope that microscopic cleavage will be noted. For example, the latter is usually the case with localized EB simplex although we can still usually demonstrate cleavage in distant skin if it is pretreated in this manner. A 4 mm. punch biopsy should then be taken of this area and the entire specimen then placed into immunofluorescence transport medium (BL, Zeus or Michel’s). Once the tissue is in this particular solution then it can be sent at room temperature to our laboratory for evaluation.
  Lesional tissue be sent since frequently it contains multiple artifactual as well as true cleavage planes, thereby making diagnosis very difficult. In addition, the presence of a blister usually is associated with the release of enzymes which tend to digest the skin proteins such that we cannot satisfactorily get antibodies to react with the specific antigens.
  Skin be obtained from the palms or soles, since the overall thickness of that tissue makes it very difficult to demonstrate skin cleavage or early blister formation.
  Fine JD, McGrath J, Eady RA. Inherited epidermolysis bullosa comes into the new millennium: A revised classification system based on current knowledge of pathogenetic mechanisms and the clinical, laboratory, and epidemiologic findings of large well defined patient cohorts. J Am Acad Dermatol. 2000; 43:135-37.