Can seborrheic dermatitis of the scalp cause hair loss?

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

Seborrheic dermatitis refers to hyperfunction of the sebaceous glands, clinically characterized by excessive scalp oiliness, shiny and greasy hair, 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 typically appear as bright red or yellowish-red patches covered with greasy scales or crusts, often accompanied by pruritus of varying severity. Initially, lesions manifest as small, follicular papules that gradually coalesce into yellowish-red plaques of varying sizes, overlaid with greasy scales and crusts. In more severe cases, the condition may progress to a mildly exudative, eczematous dermatitis.

Typically, the condition begins with increased scalp oiliness and dandruff, along with itching. Subsequently, significant hair shedding occurs during combing and shampooing. Hair gradually thins over the vertex and temples, and the scalp in affected areas becomes thinner, smoother, and exhibits progressive follicular atrophy.

Additionally, hair loss may result from excessive mental stress, overexertion of the brain, or excessive consumption of tobacco and alcohol—factors that contribute to internal accumulation of damp-heat. This damp-heat ascends upward, stimulating excessive sebum production in the scalp. Under the constant temperature and oxygen-rich environment of the scalp, this excess sebum oxidizes into fatty acids, which are then 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.