The human body contains many natural polymers, such as proteins and nucleic acids. Cellulose, another natural polymer, is the main structural component of plants. Most natural polymers are condensation polymers, and in their formation from monomers water is a by-product.
Alopecia areata is one type of hair loss that typically causes patches of baldness. In some cases, total baldness develops. In many cases, the hair re-grows, typically after several months. In some cases, the hair loss is permanent.
Alopecia areata is an autoimmune disease that causes the hair to fall out in patches. Another cause of hair loss is a condition called cicatricial alopecia, in which the hair follicles that produce hair are destroyed. Hair loss can be experienced by people with certain types of anemia, anorexia, and thyroid disease.