Peculiar proliferations emanate from different loci of the follicle, among them the sebaceous duct and outer sheath. Nearly half of them come from the region of the bulb. Some proliferations resemble caput Medusa, and some of them are pedunculated.

Sanderson rediscovered "the bulge" and the proliferations that constitute it (F. Pinkus), and he rediscovered pedunculated "bubbles" (Zimmermann).