Histopathology of scarring alopecia in Indian patients

Diagnosis of scarring alopecias (SAs) are challenging, especially when lesions late in the process of development are met with. There is a paucity of literature that profiles the role of histopathology in unscrambling this puzzle, especially in Indian patients. Our aim is to review the histological features of SA in Indian patients and attempt to assign a specific diagnosis.

We reviewed 37 cases of SA from 2005 to 2009. Sections were assessed for various histological parameters.

There were 18 of 37 cases (49%) of lupus erythematosus, 15 of 37 (41%) lichen planopilaris (LPP), 1 folliculitis, and 3 alopecia areata. The important findings in lupus erythematosus are epidermal atrophy, papillary dermal fibrosis, mucin, peribulbar inflammation, and haphazard spacing of scars. LPP shows an essentially normal epidermis, peri-infundibular infiltrate, and even spacing of scars. Twelve cases had total absence of follicles and yet could be classified based on the connective tissue changes. Alcian blue-periodic acid-Schiff stain highlighted follicular remnants within scars in 9 cases. Three cases of alopecia areata demonstrated peribulbar inflammation, evenly spaced scars, and remnants of catagenic basement membrane. Cases termed as "pseudopelade" clinically were predominantly LPP on histology.

Histopathology is a dependable tool in identifying the underlying cause in SA. Even in cases that show a complete loss of follicles, it is possible to suggest the etiology based on epidermal and connective tissue changes.