Value of transverse section scalp biopsy in alopecia areata - a clinicopathological correlation.

OBJECTIVE To correlate the histopathological features of alopecia areata with clinical stage by means of transverse sectioned scalp biopsy specimens, in terms of extent and duration of disease. STUDY DESIGN Cross-sectional. PLACE AND DURATION OF STUDY Department of Dermatology, Combined Military Hospital, Kharian Cantonment, Pakistan, from January 2002 to December 2004. PATIENTS AND METHODS Fifty consecutive patients with alopecia areata were included in the study. Four millimeter punch biopsy was taken and representative horizontal sections from lower and upper dermis were examined. Patients were divided according to disease extent i.e. Group I (<25% of scalp surface area), Group II (25 - 75% of scalp surface area) and Group III (>75% of scalp surface area including alopecia totalis and universalis). Patients were also analyzed according to the disease duration, i.e. 0-6 months, > 6-12 months, > 1-5 years and > 5 years. Follicular unit counts and density / mm2, terminal to vellus hair ratio, anagen to telogen ratio, cellular infiltrate and fibrosis were measured to assess the diagnosis and prognosis of disease. Chi-square test was used to assess statistical significance. RESULTS Diagnosis of alopecia areata could be made in 82% of biopsies. Follicular unit counts and density per mm2 decreased with the disease duration (p=0.01). Catagen and telogen hair follicle counts increased with disease duration (p=0.0001). Cellular infiltrate decreased and fibrosis increased with the duration of disease (p=0.0001). Anagen telogen ratio and terminal to vellus hair ratio inverted in long-standing disease. CONCLUSION Transverse section scalp biopsy can help in the diagnosis of alopecia areata and the disease stage can be predicted by analyzing the histopathological findings quantitatively.