Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body.[2] Typically at least the head is involved.[4] The severity of hair loss can vary from a small area to the entire body.[7] Inflammation or scarring is not usually present.[4] Hair loss in some people causes psychological distress.[3]
Common types include male- or female-pattern hair loss, alopecia areata, and a thinning of hair known as telogen effluvium.[4] The cause of male-pattern hair loss is a combination of genetics and male hormones; the cause of female pattern hair loss is unclear; the cause of alopecia areata is autoimmune; and the cause of telogen effluvium is typically a physically or psychologically stressful event.[4] Telogen effluvium is very common following pregnancy.[4]
