Dandruff and Seborrheic Dermatitis: A Head Scratcher 408 Methods of Measurement The primary efficacy measure of antidandruff activity in clinical trials is adherent scalp flaking severity. This assessment is based on a subjective 11-point flaking scale ranging from 0 (no scaling)60,70,79 to 10 (very heavy scaling). 60,63,90 The scalp is divided into eight octants and the flaking density is scored after parting the hair at each site.60-62 The score from each site is summed across all sites (total of 80). An alternative method, the Colorimetric method (Chroma C*), called squamometry, assesses the flakes obtained on D-squame tapes collected from the most severely affected area at pre-treatment and the same site after treatment. In addition to the adherent scalp flaking scores, assessment of loose dandruff, global involvement in the disease process, and subjective assessment of itch and dandruff severity serve as secondary efficacy measures. Other secondary efficacy endpoints include the assessment of Malassezia density.91-93 These have been complimented by more accurate molecular genetic techniques32,40,94-97 in species identification and quantification. The most recent advance in assessing the therapeutic resolution of D/SD utilizes noninvasive sampling methods for molecular biomarkers. Such methods are compatible with the high capacity needed in a clinical setting and are objective endpoints. Using these tools, therapeutic resolution for ZPT-based shampoos has been demonstrated for inflammatory biomarkers (IL-1a, IL-8, histamine), hyper-proliferation (involucrin, keratins) and biomarkers of barrier integrity (human serum albumin, ceramides).14,58 Summary Dandruff is characterized by adherent or loose white flakes that accumulate on the scalp, in the hair, and on the clothing. It is accompanied by pruritis, and carries a significant social stigma in most developed countries. Seborrheic dermatitis is a more severe form of dandruff, with all the same symptoms plus visible inflammation, and often extends to the nasolabial fold, mustache and beard area of the face, and possibly the eyebrows.