What is the dry type of dandruff characterized by lightweight flakes that may attach to the scalp?

The dry type of dandruff characterized by lightweight flakes that may attach to the scalp is known as Pityriasis. This condition often presents as fine, dry flakes that are easily shed from the scalp and can be identified through their light texture. The term 'Pityriasis' specifically refers to this type of dandruff, and it indicates a mild irritation of the scalp that results in the breaking down of the skin's outer layer, leading to flaking.

In contrast, other options represent different conditions. Seborrheic dermatitis is a more severe form of dandruff that involves oily, yellowish flakes and inflammation. Pediculosis pertains to a lice infestation, which is an entirely different issue related to parasitic presence on the scalp. Folliculitis is an inflammation of the hair follicles often caused by bacteria or fungi, which can be confused with dandruff but is not characterized by the specific lightweight flakes that indicate Pityriasis.