Final answer:
Psoriasis is a skin disease that causes thick, crusty patches of red irritated scalp. It results from the complex interplay between keratinocytes, dendritic cells, and T cells.
Step-by-step explanation:
The disorder that refers to thick, crusty patches of red irritated scalp is known as psoriasis. Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales on various parts of the body including the scalp. It results from the complex interplay between keratinocytes, dendritic cells, and T cells.