Hair Disorders

M.D. Claiborne & Associates, L.L.C. - Dermatology Specialists

Hair grows on human skin in various textures, colors, and density. The structure from which each hair grows is called a follicle. Muscles, oil glands (sebaceous glands), and nerves extend from the follicle into the next layer of the skin — the dermis. Throughout life, the skin is constantly shedding dead skin cells and growing new ones. This happens all over the skin. Inside the follicles, sebum (oil) carries the dead cells to the surface. Various factors can interfere with the cycle of renewal and disposal, and a number of disorders can result.Folliculitis is infection and inflammation of the hair follicles. The condition may be superficial (i.e., on the surface of the skin) or deep within the follicles. Hair follicles become red and irritated, and pus-filled lesions form. Folliculitis can clear up by itself in a matter of a couple of weeks or become more persistent and thus require treatment.

The most common cause of folliculitis is infection by the bacteria Staphylococcus aureus. Other species of bacteria may also be responsible. For example, contaminated water in whirlpools and hot tubs can transmit Pseudomonas aeruginosa, which can cause folliculitis. This bacterium may also be passed in wet suits.

What is Alopecia?

Alopecia is the medical term for baldness. According to the American Medical Association, 95% of cases involve androgenetic alopecia, also known as common baldness or, in men, male pattern baldness. Androgenetic alopecia is an inherited condition that affects about 25% of men before the age of 30 and two-thirds of all men before the age of 60. The condition is less common and less extreme in women. It can develop in older adults, resulting in an overall thinning of all the scalp hair rather than complete baldness.

The Structure of a Hair Follicle

The Structure of a Hair Follicle

Alopecia areata and androgenetic alopecia are types of nonscarring alopecia, that is temporary hair loss that does not result from damaged hair follicles. Scarring alopecia is permanent hair loss that results from damaged hair follicles. There are other forms of scarring and nonscarring alopecia caused by skin diseases and underlying illness. Dr. Claiborne may need to do a scalp biopsy to determine whether the cause of your alopecia is due to a scarring or non-scarring alopecia.

Your treatment options may include topical treatments, oral treatments, or injectable treatments depending on the cause of your hair disorder.

Hair
Hair is made up of keratin, a protein found in the nails and outer layer of the skin. Each hair is rooted in a hair follicle, a tiny indentation in the outer layer of the skin (epidermis). Hair follicles are made up of cortical, or matrix, cells that proliferate and keratinize into the hair.

Hair grows about one-half inch (10–15 mm) every month and a single hair can last as long as 10 years. There are 3 phases of the hair growth cycle:

Hair Shaft

Anagen, the active growth phase, lasts about 1000 days. At any given time, 90% of a person’s hair is in the anagen phase. Catagen, the transition phase, lasts a few weeks. During catagen, the growth of hair stops abruptly. Only about 1% of hair is in catagen at any given time. Telogen, the resting phase, lasts about 100 days. There is no activity during this final phase and, at the end, the hair sheds.

The average adult loses about 50-100 hairs a day. Only in certain circumstances (e.g., pregnancy, telogen effluvium) are all hairs in the same phase of the growth cycle.