Yadav D, et al. - Researchers evaluated whether horizontal sections of scalp biopsies have utility in differentiating between androgenetic alopecia (AGA) and alopecia areata (AA). They found that transverse sections of scalp biopsies that favored AA over AGA showed a lower anagen:non-anagen hair ratio and presence of pigment casts, besides peribulbar inflammation.

Methods

• Researchers performed this prospective, cross-sectional study including 20 cases of male AGA, 11 of female AGA and 21 cases of AA.
• They performed clinical examination and dermoscopy, after which a skin biopsy was taken and subjected to transverse sectioning.
• Two dermatopathologists blinded to clinical details performed histopathological evaluation.

Results

• AA cases demonstrated significantly lower terminal:vellus hair ratio (3.08 in AGA and 1.83 in AA, p=0.0091) and anagen:non-anagen hair ratio (9.25 in AGA and 3.56 in AA, p=0.0021) among the quantitative parameters assessed.
• In qualitative parameters, 63% of AA cases showed peribulbar inflammation (p=0.0001).
• In twice the number of AA (57%) than AGA (26%) cases, pigment casts were detected.
• In 9.5% of AA cases, broad avascular stelae and focal trichomalacia were found.