P13 DANDRUFF SKIN MORPHOLOGY AND IMPACT OF THE USE OF AN ANTI-DANDRUFF PRODUCT

James R. Schwartz, Thomas L. Dawson, Jr., Ronald R. Warner and Y. Boissy  The Procter & Gamble Co., Cincinnati, OH 45241

Symptomatic dandruff entails flaking and itching of the scalp.  We show that the stratum corneum (SC) in such cases is highly irregular.  Transmission electron microscopy of scalp tape strips indicates a hyperproliferative state: parakeratosis, lipid droplets within corneocytes, few desmosomes, corneocyte membrane interdigitation and excessive disorganized intercellular lipid.  Visual flaking of the scalp occurs in patches, but the abnormalities which occur in the SC are throughout the scalp, even where no flaking is present.  These abnormalities are very different than those seen with typical “dry skin” and have implications as to the etiology of dandruff.  A protocol was developed whereby these morphological changes could be quantified by scoring the micrographs for a number of relevant parameters.  Using this methodology, a relationship was demonstrated between the severity of the SC ultrastructural abnormalities and the severity of visual flaking.  In a three-week clinical evaluation of a commercial zinc pyrithione-based anti-dandruff shampoo, improvements in stratum corneum ultrastructure accompanied the visual reduction in flaking.  This occurred for the anti-dandruff shampoo to a significantly greater extent than for a placebo product.  This data demonstrates that dandruff is more than a superficial abnormality and that complete treatment of the disease requires products that can address the root cause of the problem and not simply symptomatic treatment.