Does seborrheic dermatitis of scalp cause extreme hair loss?

Seborrheic dermatitis is a form of skin inflammation (dermatitis) that causes a red, oily, flaking skin rash in areas of the body where glands in the skin called sebaceous glands are most abundant, such as the scalp. When seborrheic dermatitis affects the scalp, it appears as either patchy or diffuse areas of redness and flaking. The condition can lead to hair loss, but the amount of hair loss is usually not significant unless there is persistent, aggressive scratching.