The average person has 5 million hairs. Hair grows all over your body except on your lips, palms, and the soles of your feet. It takes about a month for healthy hair to grow half an inch. Most hairs grow for up to six years and then fall out. New hairs grow in their place.
Hair helps keep you warm. It also protects your eyes, ears and nose from small particles in the air. Common problem with the hair and scalp include hair loss, infections, and flaking.
Hair disease may refer to excessive shedding or baldness (or both). Balding can be localised or diffuse, scarring or non-scarring. Increased hair can be due to hormonal factors (hirsutism) or non-hormonal (hypertrichosis). Scalp disorders may or may not be associated with hair loss.