<unk>  is a common skin condition in which a protein in the skin called keratin forms hard plugs within hair follicles.
Keratosis pilaris
Dermatosis papulosa nigra
Dermatosis neglecta
Hydroa vacciniforme
Dyschromatosis universalis
Epidermodysplasia verruciformis
Linitis plastica
Keratosis obturans