Follicular mucinosis is a term that encompasses three related entities. Alopecia mucinosa, Urticaria-like follicular mucinosis, and cutaneous lymphoma related follicular mucinosis all share similar features when skin biopsies are examined under the microscope. Because these entities are uncommon, many authors discuss and categorize these entities in different ways.

Alopecia mucinosa, also known as Pinkus’ follicular mucinosis or mucinosis follicularis is an abnormal accumulation of a normal substance, mucin, in hair bearing skin. For some unknown reason (thought to be related to our immune system) cells in the hair follicle produce an abnormal amount of mucin causing a variety of skin lesions including hair loss (alopecia) and sometimes scarring. It is found in children or adults in the 3rd or 4th decade of life. The adult form tends to have more skin lesions and be last longer than the form typically found in children. A variety of treatments have been tried with some success but most lesions resolve within months to two years.

Urticaria-like follicular mucinosis is very rare. It usually occurs in middle aged men on the head and neck. Red lesions are often seen and hair loss is rare. The disease can last for years and may resolve on its own. It is not thought to be associated with any systemic diseases.

Follicular mucinosis may also be found in connection with lymphomas of the skin. Alopecia mucinosis is distinguished from lymphoma related follicular mucinosis by microscopic evaluation and gene rearrangement studies.