| Retention of the sebaceous secretions, and dilation of the follicle, may lead to cyst formation. |
| Sebaceous glands develop at puberty in response to androgen stimulation and are attached to the follicle canal by sebaceous ducts. |
| Then, a fluid-filled space develops, to form the antrum of a tertiary follicle. |
| If the plugged follicle, or comedo, stays beneath the skin, it is called a closed comedo and produces a white bump called a whitehead. |
| Earliest changes in the hair follicle occur when the follicular canal becomes blocked with abnormally keratinized desquamating cells. |
| Each hair is made of tough and stretchable protein called keratin, manufactured by the hair follicle. |
