Abnormal skin morphology Keratosis pilaris 2018-12-02T13:20:11Z Follicular plugging Follicular keratotic plug HP:0040180 Follicular keratosis An anomaly of the hair follicles of the skin that typically presents as small, rough, brown folliculocentric papules distributed over characteristic areas of the skin, particularly the outer-upper arms and thighs. Chicken skin Keratosis pilaris is characterized by abnormal keratinisation of the lining of the follicular infundibulum (the upper portion of the hair follicle). Keratin (i.e., scale) fills the follicle instead of exfoliating. Clinically, the keratotic plugs have been referred to as the carpet tack sign since they project up similar to carpet tacks. Carpet tack sign Lichen pilaris Hyperkeratosis pilaris