Final answer:
A follicular cast is a structure within the hair follicle made up of sebum, dead skin cells, and other debris, which can lead to blockages and is associated with conditions such as dandruff and folliculitis.
Step-by-step explanation:
A follicular cast is a dermatological condition where a cylindrical structure forms within a hair follicle, typically consisting of sebum, dead skin cells, and other debris. This can lead to the blockage of hair follicles and may be associated with various scalp conditions, such as dandruff, psoriasis, or folliculitis.
Folliculitis is characterized by inflamed hair follicles, often presenting as itchy, red, and sometimes pus-filled bumps. It may result from various factors, including sweat, skin injuries, ingrown hairs, and irritation from shaving. Folliculitis can be a self-limiting condition but may require medical treatment if it is persistent or severe.
The skin condition acne is also related to inflammation of hair follicles, where the follicles are clogged with lipids, fatty acids, and dead skin cells, creating a breeding ground for bacteria.