Fig 4.

Lesional area and senstivity (LAD) score calculation. If the LAD score is used for determination of the response to a given treatment, for example, in the assessment of response to intralesional steroids, it is best if the area(s) of alopecia chosen to track is clearly demarcated from the surrounding hair. If the margins of the areas are instead less clear, as in the areas in Fig 4 marked A and B, then one should consider marking the edges of the alopecic patch directly on the scalp and taking a representative photograph so that there is a record of which margins were used at the initial assessment. The area of each patch is determined by multiplying the long axis by its perpendicular axis. If the patch of alopecia is totally circular, πr² may be used instead. This method will require determining ways of identifying these areas of alopecia on subsequent visits (landmarks, photographs, and/or tattoos). Target area A is a 4-cm diameter circular patch of alopecia with an area of πr² = 3.1416 × (4/2)2 = 12.57 cm². The density of this area equals 90% hair loss. The area x density = 12.57 × 90/100 which is a LAD score of 11.31. Target area B is a × 3 2.5-cm patch of alopecia with an area of 7.5 cm². The density of this area equals 98% hair loss. The area X density = 7.5 × 98/100 which is a LAD score of 7.35. The overall LAD score equals A + B = 11.31 + 7.35 = 18.66.CAPSULE