Which scalp condition is characterized by excessive flaking?

Dandruff, also known as seborrheic dermatitis, is characterized by excessive flaking of the scalp. This condition typically results in the shedding of dead skin cells, which can appear as white or yellowish flakes on the scalp and may also be visible on the shoulders and clothing. Dandruff is often accompanied by itching and can be a source of discomfort and self-consciousness for those affected.

While psoriasis and eczema can also involve scaling and flaking, they are distinct conditions with different characteristics. Psoriasis is an autoimmune disease that results in thick, red patches covered with silvery scales. Eczema is a general term for various inflammatory skin conditions that can lead to itchy, inflamed skin but does not primarily manifest through excessive flaking of the scalp as a singular symptom. Alopecia is related to hair loss and does not describe a condition characterized by flaking.

Thus, the defining feature of excessive flaking directly links to dandruff (seborrheic dermatitis), making it the correct answer.