Can seborrheic dermatitis of the scalp cause hair loss?

Seborrheic dermatitis of the scalp is a skin condition primarily caused by excessive sebum production on the scalp. In severe cases, it may lead to hair loss. Details are as follows:

Seborrheic dermatitis refers to hyperfunction of the sebaceous glands, manifesting as excessive oiliness, shiny scalp, and prominent scaling. It commonly occurs in areas rich in sebaceous glands and represents a chronic inflammatory condition arising on the basis of seborrhea. Lesions appear as bright red or yellowish-red patches covered with greasy scales or crusts, often accompanied by pruritus of varying severity. Initially, lesions present as small, follicular papules that gradually coalesce into yellowish-red plaques of varying sizes, covered with greasy scales and crusts. In more severe cases, the condition may resemble mild exudative eczematous dermatitis.

Typically, the condition begins with excessive scalp oiliness and dandruff, along with pruritus. Subsequently, significant hair shedding occurs during combing and shampooing. Hair gradually thins over the vertex and temples, while the scalp in affected areas becomes thinner, smoother, and the hair follicles progressively close.

Additionally, hair loss may result from excessive mental stress, overuse of the brain, or excessive consumption of tobacco and alcohol—factors that contribute to internal accumulation of damp-heat. This damp-heat rises upward, stimulating excessive sebum production on the scalp. Under the constant temperature and oxygen-rich environment of the scalp, this excess sebum oxidizes into fatty acids, which are reabsorbed by the hair follicles. This process damages the follicular epithelial cells and causes ischemia and hypoxia in the deeper structures of the hair roots, ultimately leading to hair loss.