Hair Loss Classification System
The Norwood Hamilton Scale is a way to measure the extent of male pattern baldness, and is the generally accepted standard when describing hair loss for men in general.
Men typically lose hair in several patterns. The most common are receding at the temples, on the top back of the head (known as the vertex), and diffuse thinning where hair over large areas begins to thin, without a specific change to the hairline. Combinations of these types of losses also occur. The Norwood Hamilton Scale can be used to categorise your level of male pattern baldness.
A hair loss clasification system is also important as a common reference point against which to measure the efficacy of available treatment options. The further along you are on the Norwood scale, generally speaking, the fewer options you have. At levels 5 and higher, the effectiveness of treatments such as minoxidil or finasteride becomes highly limited. I will use the Norwood Hamilton Scale throughout this site to indicate for whom a particular treatment option might be suitable.
Types of Hair Loss
The most common type of hair loss in males is male pattern baldness (also known as androgenetic alopecia). Male pattern baldness is, essentially, the preoccupation of this site and has already been discussed in detail.
Other types of hair loss, according to wikianswers, are:
Telogen Effluvium: This condition is also referred to as diffuse hair loss. In this type of hair loss, a lot of hair is lost in a short span of time. Leading causes for this condition are pregnancy, chemotherapy for cancer treatment, very high fevers, severe illnesses, and sometimes even high levels of stress can result in telogen effluvium. This is not a permanent condition and most of the lost hair does grow back within a few months. Some sudden events that can contribute to this condition are childbirth, surgery, and severe emotional stress (death of loved ones, abuse, accidents, or other traumatic events.
Alopecia Areata: Any sudden loss of hair resulting in bald patches is the condition of alopecia areata. This is an autoimmune disease where the hair follicles are attacked by the body. Why it happens has not yet been discovered. It can be a mild case and result in bald patches on the head or if it is severe it can affect the entire body hair. This condition usually treats itself without any medication although some doctors may prescribe certain steroid injections for repeated occurrence of localized alopecia areata.
Traction Alpoecia: This type of hair loss occurs in people who routinely pull on their hair through harsh brushing or hairstyles such as a tight ponytail that pull on the hair. One prime example of this condition is the braided hair popular with African-americans.
Medication Related Hair Loss: Certain medicines such as accutane, allopurinol, and anti-thyroid medicines are known to cause hair loss.
Diet Related Hair Loss: Temporary hair loss and hair shedding can result from poor nutrition and an unbalanced diet. If your body is deficient in certain minerals, vitamins, and/or iron, it can cause you to lose hair.