Which scalp condition is characterized by excessive flaking?

Dandruff, also known as seborrheic dermatitis, is characterized by excessive flaking of the scalp. This condition occurs when the scalp's oil glands produce an excess of sebum, leading to the rapid turnover of skin cells. As these cells accumulate and die, they form visible flakes that can be seen on the scalp and in the hair. Dandruff can be triggered by various factors, including dry skin, sensitivity to hair products, and certain medical conditions.

In contrast, psoriasis is a chronic skin condition that can affect various parts of the body, including the scalp, leading to thick, red patches covered with silvery scales. While it can produce flaking, it's generally more severe and involves inflammation.

Scalp acne refers to the presence of pimples on the scalp due to clogged pores and is more about inflammation and pustules rather than excessive flaking.

Folliculitis is the inflammation of hair follicles, often resulting in red bumps and pustules, rather than the noticeable flakes associated with dandruff.

Thus, dandruff specifically highlights excessive flaking, making it the correct choice in this context.