Table 1.

Description of Correlation between HP and RCM Criteria in AAI.

Histopathological criteria	RCM features
Peribulbar and dermal mild inflammatory infiltrate	Round-to-polygonal, mildly refractive cells around the hair bulb at the level of the superficial dermis
Miniaturized follicles	Reduction of the caliber of the hair shaft in comparison to normal hair as well as reduction of the caliber of the adnexal infundibulum
Infundibular ostia empty or full of sebum and keratin	Dark infundibula unit (empty) or highly refractive material inside the infundibula (full of sebum and keratin)
Catagen and telogen germinal units	Catagen: infundibular units connected to the hair shaft Telogen: dilated infundibular unit associated to fibrotic tissue at the level of the superficial dermis Increased catagen: 2 to 3 (then, repeat the chosen description) Increased telogen: 1 to 2 (then, repeat the chosen description)
Follicles in telogen	Dilated infundibular unit associated to fibrotic tissue at the level of the papillary dermis
Fibrous tracts or streamers	Pale, ill defined, sometimes compact fibers at the level of the superficial dermis

Abbreviations: AAI, alopecia areata incognita; HP, histopathology; RCM, Reflectance confocal microscopy.