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.
Some conditions produce small areas of hair loss, while others affect large areas of the scalp. Common causes of patchy hair loss are. 1  alopecia areata (small circular or coin size patches of scalp baldness that usually grow back within months), 2  traction alopecia (thinning from tight braids or ponytails), 3  trichotillomania (the habit of twisting or pulling hair out), 4  tinea capitis (fungal infection).