122 Stereological Analysis of Activated Eccrine Glands in Alopecia Areata Using the Silastic Mold Technique

K. Lockhart, M. Ericson, N. Beheshti, and M. Hordinsky Department of Dermatology, University of Minnesota Academic Health Center, Minneapolis, Minnesota, USA

Eccrine gland function has been hypothesized to be abnormal in patients with alopecia areata. In this study, eccrine gland function was studied in six patients with extensive scalp alopecia areata (>90% hair loss) and six age- and sex-matched controls. Eccrine glands were stimulated by iontophoresis using 1% pilocarpine at 2mA direct current for 5 minutes on the scalp, above the left ear, and at a site on the dorsum of the left hand. Sweat droplet impressions were collected in silicone (Silastic) molds at 0, 15, and 30 minutes after stimulation and evaluated by stereology. Stereology is an accepted, unbiased method for collecting information about number, length, surface area, and volume of specimens. Though eccrine gland analysis by the Silastic mold technique is considered to be more sensitive than evaporimetry, especially when combined with computerized image analysis, interpreting the Silastic molds can vary because of mold thickness, pooling of droplets, or interference of other cutaneous appendages. Therefore, the techniques used in this study were evaluated for reproducibility. We studied eccrine gland function in three control subjects on three different days with visits occurring 1 to 2 weeks apart. Reproducibility of the stereology technique was assessed by blinding the observer to subject, status (patient or control), and time period. We found no difference in eccrine gland function, between patients and controls, on the hand (p = 0.221) or the scalp (p = 0.669). Stereology proved to be highly reliable for analysis of the molds (R = 0.974, N = 18), but eccrine gland stimulation and collection showed a 35.7% variability. While the pilocarpine stimulation/Silastic mold technique was not reproducible on a week-to-week basis, stereology proved to be a consistent tool for unbiased analysis of the Silastic molds. Future studies should be directed towards testing of alopecia areata patients and controls for several days to obtain an average estimate of eccrine gland function with the pilocarpine stimulation/Silastic mold technique and stereology.