A disorder that refers to thick, crusty patches of red irritated scalp is known as?

The disorder characterized by thick, crusty patches of red irritated scalp is known as psoriasis. Psoriasis is an autoimmune condition that leads to the rapid growth of skin cells, resulting in the buildup of scales and red patches that can cause discomfort or itching. It commonly affects areas such as the scalp, elbows, and knees, and the patches are often thick, silvery-white, and may be associated with inflammation.

In the context of this question, while dermatitis, eczema, and folliculitis are also skin-related conditions, they present differently. Dermatitis generally refers to inflammation of the skin that can manifest as red, itchy, or inflamed areas but does not typically have the thick, crusty appearance of psoriasis. Eczema, often used interchangeably with dermatitis, similarly refers to dry, itchy patches but lacks the distinctive thick scaling of psoriasis. Folliculitis involves inflammation of hair follicles, leading to red bumps and possible pustules, typically without the crusty patches associated with psoriasis. Thus, the distinctive presentation and characteristics of psoriasis make it the correct answer for this question.