Trichilemmal cyst Trichilemmal cyst A trichilemmal cyst, also known as a wen, pilar cyst or isthmus-catagen cyst, is a common cyst that forms from a hair follicle. They are most often found on the scalp. The cysts are smooth, mobile and filled with keratin, a protein component found in hair, nails, skin, and horns. They are, however, clinically and histologically distinct from trichilemmal horns, which are much more rare and not limited to the scalp. Trichilemmal cysts may run in families and they may or may not be inflamed and tender, often depending on whether they have ruptured. Rarely, these cysts may
Hair removal been used in attempts to eradicate lice or to minimize body odor due to accumulation of odor-causing micro-organisms in hair. Some people with trichiasis find it medically necessary to remove ingrown eyelashes. Shaving against the grain can often cause ingrown hairs. Many forms of cancer require chemotherapy, which often causes severe and irregular hair loss. For this reason, it is common for cancer patients to shave their heads even before starting chemotherapy. In extreme situations people may need to remove all body hair to prevent or combat infestation by lice, fleas and other parasites. Such a practice was used, for