Hair loss and male pattern baldness can be a rather intimate issue for men of all ages. The fact that there are several different types of baldness complicates the issue when treatments are being considered. This is especially true with over the counter treatments for baldness, including Minoxidil and Finasteride.

The Norwood Classification System:

In 1975, Dr. O’tar Norwood established the Norwood classification system for identifying the different types and phases of balding in men. The Norwood system is the most widely used classification for hair loss in men, and is used by most hair restoration surgeons in determining the proper action to address balding. It defines two major patterns of baldness and several less common types. In the regular Norwood pattern, two areas of hair thinning — a bitemporal recession and thinning crown — gradually enlarge and coalesce until the entire front, top and crown (vertex) of the scalp are bald. There are seven classes of hair loss in the Norwood classification system.

Class I :

The first Norwood class for male hair loss represents an adolescent or juvenile hairline and is not actually considered “balding.” The adolescent hairline generally rests on the upper brow crease.

Class II:

The second class indicates a progression to the adult or mature hairline that sits a finger’s breath (1.5cm) above the upper brow crease, with some temporal recession. This also does not represent balding.

Class III:

Norwood class III is the earliest stage of male hair loss. It is characterized by a deepening temporal recession, commonly referred to as a receding hairline.

Class III:

The third class, also known as the “Vertex” class, represents early hair loss in the crown of the head (vertex).

Class IV :

The fourth class in the Norwood system is characterized by further frontal hair loss and enlargement of vertex. However, there is still a solid band of hair across top separating front and vertex.

Class V:

In the fifth class, the bald areas in the front and crown continue to enlarge and the bridge of hair separating the two areas begins to break down.

Class VI :

Class VI occurs when the connecting bridge of hair disappears, leaving a single large bald area on the front and top of the scalp. The hair on the sides of the scalp remains relatively high.

Class VII:

Patients in the final Norwood class have extensive hair loss with only a wreath of hair remaining in the back and sides of the scalp.

Norwood Class A:

Separate from the 7 classes mentioned above, the Norwood Class A patterns are characterized by a front to back progression of hair loss. Norwood Class A’s lack the connecting bridge across the top of the scalp and generally have more limited hair loss in the crown, even in advanced stages.

Norwood Class A patterns are far less common in most men than the regular pattern (less than 10% of adult men). These patterns are still deemed significant because of the fact that, since the hair loss is most dramatic in the front, the patients look very bald even when the hair loss is minimal.

Because the frontal bald area is not generally responsive to medication, men with Class A hair loss often seek surgical hair restoration early. Additionally, the dense donor area contrasts and accentuates the baldness on top. Fortunately, Class A patients are excellent candidates for hair transplantation.

Male Pattern Baldness:

Diffuse Patterned and Unpatterned Alopecia -

Two other types of genetic hair loss in men not often considered by doctors, “Diffuse Patterned Alopecia” and “Diffuse Unpatterned Alopecia”, pose a significant challenge both in diagnosis and in patient management. Understanding these conditions is crucial to the evaluation of balding in both men and women, particularly those that are young when the diagnoses may be easily missed, as they may indicate that a patient is not a candidate for surgery.

Diffuse Patterned Alopecia (DPA) is an androgenetic alopecia — commonly known as male pattern baldness — manifested as diffuse thinning in the front, top and crown, with a stable permanent zone. In DPA, the entire top of the scalp gradually miniaturizes (thins) without passing through the typical Norwood stages. Diffuse Unpatterned Alopecia (DUPA) is also androgenetic, but lacks a stable permanent zone and affects men much less often than DPA. DUPA tends to advance faster than DPA and end up in a horseshoe pattern resembling the Norwood class VII. However, unlike the Norwood VII, the DUPA horseshoe can look almost transparent due to the low density of the back and sides. Differentiating between DPA and DUPA is very important because DPA patients often make good transplant candidates, whereas DUPA patients almost never do, as they eventually have extensive balding without a stable zone for harvesting.