Hair loss can occur as hair thinning, without hairs noticeably falling out, or as hair shedding, with clumps of hair falling out. The most common type of hair loss is androgeneti alopecia, male-pattern hair loss or female-pattern hair loss. Men tend to lose hair on the front hairline and forehead and on top of the head; eventually, only hair around the ears, the sides, and back of the head remains. Women have diffuse hair thinning throughout the scalp...

In men, thinning hair on the scalp, a receding hairline, or a horseshoe-shaped pattern that leaves the crown of the head exposed. In women, thinning of hair in general, but mainly at the crown; complete balding is rare. In children or young adults, sudden loss of patches of hair; known as alopecia areata. Complete loss of all hair on the body; a rare disease called alopecia universalis. Especially in children, patches of broken hairs and incomplete hair loss, usually on the scalp but sometimes involving the eyebrows; the child is most likely rubbing or pulling out hair, a condition trichotillomania.

Excessive shedding of hair, but not complete baldness, associated with various illnesses and drug treatments, rapid weight loss, anemia, stress or pregnancy; a condition known as telogen effluvium. Hair shedding, when clumps of hair fall out, may be a symptom of a disease or disorder that causes hairs to break or to pull out at the follicle, the sheath that surrounds the root of a hair. The pattern of other types of hair loss, such as alopecia areata, trichotillomania, and traction alopecia, usually occurs in distinct patches, and less commonly as overall thinning, as in the case of telogen effluvium.