Alopecia is a condition where hair is lost from some or all of the body, usually from the scalp. It is an autoimmune skin disease that affects both men and women.
Alopecia areata is a type of hair loss that occurs when your immune system mistakenly attacks hair follicles, which is where hair growth begins. The damage to the follicle is usually not permanent. Alopecia areata can occur at any age, it affects both women and men equally. Alopecia areata usually begins when clumps of hair fall out, resulting in totally smooth, round hairless patches on the scalp usually around coin sized shapes. In some cases the hair may become thinner without noticeable patches of baldness, or it may grow and break off, leaving short stubs (called “exclamation point” hair). In rare cases, complete loss of scalp hair and body hair occurs. The hair loss often comes and goes—hair will grow back over several months in one area but will fall out in another area.
Androgenetic alopecia is the most common type of progressive hair loss. It is also known as malepattern baldness, female-pattern baldness, or just common baldness. It affects about 50% of men over the age of 50, and about 50% of women over the age of 65. In women the severity varies, it may present as widespread hair thinning but in some cases it can lead to complete baldness. Androgenetic alopecia is caused by a combination of genetic and hormonal factors.