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Norwood Male Pattern Baldness Scale of Hair Loss

1975, Dr. Norwood published his famous hair loss classification chart in the Southern Medical Journal. This chart would eventually be known as the Norwood Chart of Male Pattern Baldness. To produce this chart, he took a classification chart published by Hamilton in 1949 and improved it with more detail, more stages, and used more men in his study as a dermatologist in Oklahoma City during the 1970s.

Norwood determined there were two basic types of hair loss in men with androgenetic alopecia, male pattern baldness. The first type, or Regular Type, is the predominant type in 97 percent of all 1,000 men that Norwood studied. The Regular Type shows hair loss at Class 3 and is noticeable with hair loss at the temples and crown (also called the vertex, Fig. 1 see Baldness Map, below) which eventually merge into one continuous, uninterrupted bald area. This "front to back" style of male pattern baldness is visible in the "Regular Chart" below.

Fig. 1, Baldness Map

The second type, Type A variant, constituted the other 3 percent of men in the study.

"It is distinguished by two major features and two minor features. The major features must be present to make the Type A designation. The minor features are not necessary but are frequently present. 1. The entire anterior (frontal) border of the hairline progress posteriorly without leaving the usual island or peninsula of hair in the mid-frontal region. 2. There is no simultaneous development of a bald area on the vertex. Instead, the anterior recession just keeps advancing posteriorly to the vertex (crown)." (1)

Now, this is not to say that Type A variant men do not suffer crown hair loss, only that it comes at the end of the hair loss pattern. For either type, one's future hair loss pattern can be generally be predicted by noting the point at which they are currently, and following it's logical progression.

For example, a Class 3 usually becomes a Class 4, and then 5 and so on. A type A variant might start as a 3a, then move to 4a, and then 5a.

However, Norwood himself pointed out this wasn't always the case and evolution and progression rate might differ among men.

"The standards depicted in (Figures 4 and 5) categorize typical sequences in the development of male pattern baldness. There are varied patterns of male pattern baldness and no single sequence is followed uniformly by all subjects. Some individuals will fall between sequences at the time of examination, but most subjects can be classified quite closely." (1)

In a page published on his website, hair transplant pioneer Dr. Shelly A. Friedman points out that sometimes, a class 2 may thin diffusely and directly evolve into a class 6 or 7. "We call this later process Diffuse Patterned Alopecia." (2)

Fig. 2

Norwood Chart
"Regular Type"
97% of men

Description of Class (6)

Norwood Class 1 Hair Loss Class 1: A hairline that most closely resembles men in their teenage years or as a young man. There is basically no temporal recession or very minimal temporal recession of the hairline.
Norwood Class 2 Hair Loss Class 2: Hair begins to recede above the temples to a point no greater than 2 cm from the mid-frontal peak which might also recede a little bit leaving a slightly higher forehead.
Norwood Class 3 Hair Loss Class 3: "This represents the minimal extent of hair loss considered sufficient to represent baldness," wrote Norwood. Most class 3 scalps have deeper temporal recession, greater than 2 cm, and higher mid-frontal hair loss leaving a higher forehead.
Norwood Class 3 vertex Hair Loss Class 3 Vertex: In this type, hair loss is primarily in the vertex (crown hair loss) with possibly some frontal recession, but does not exceed that seen in class 3 above. "This type of baldness is most common with advancing age."
Norwood Class 4 Hair Loss Class 4: Further frontal and temporal hair loss, more severe than class 3. "Also, there is a sparseness or absence of hair on the crown area. These areas are extensive but separated from each other by a band moderately dense hair that extends across the top."
Norwood Class 5 Hair Loss Class 5: The frontal and temporal regions extend further backwards towards the crown (vertex) as the crown becomes much larger with a separation band of hair that is less dense and distinct as it was in class 4.
Norwood Class 6 Hair Loss Class 6: The bridge of hair that separated the fronto-temporal hair loss from the crown is now gone, and the two balding regions have merged into one.
Norwood Class 7 Hair Loss Class 7: This is the most severe form of male pattern baldness. All that remains is a narrow horseshoe shaped band of hair which begins laterally just in front of the ear and extends quite low to the ears and ends close to the nape of the neck.

Fig. 3Type A Variant (below)

Norwood Chart
"Type A Variant"
3% of men

Description of Class (6)

Criteria for Type A Variant:
1.The entire anterior (frontal) border of the hairline progress posteriorly without leaving the usual island or peninsula of hair in the mid-frontal region. 2. There is no simultaneous development of a bald area on the vertex. Instead, the anterior recession just keeps advancing posteriorly to the vertex (crown).

Class 2a: The entire frontal border, with temples, lays high on the forehead. That midfrontal peninsula or peak of hair on the forehead is gone and only represented by a few fine, vellus hairs. The recession is less than 1 inch.
Class 3a: The area of recession of the fronto-temporal region is almost vertical with the front portion of the ear.
Class 4a: The area of recession is now past the front portion of the ear. The area behind the hairline may show thinning and fine vellus hair.
Class 5a: "This is the most advanced degree of alopecia described with this variant. If it becomes more extensive, it cannot be distinguished from the usual class 5 and 6. The area of alopecia has not reached the vertex."

Hair Loss Incidence Rates per 1,000

In building his classification chart, Norwood was able to get exact numbers for each chart class of hair loss based on age, (see Fig 4, Table 1 below).

Notice that in his findings, 3 out of 185 men (2 percent) age 18-29 are already a Class 5.

In the 40 to 49 age category, 15 men were class 4, and 5 were class 7, and so on. In the 70 to 79 group, 64 out of 102 men had class 3 or higher male pattern baldness. (1)

Unfortunately, his study only looked at 1,000 white males, and did not include blacks, asians, pacific islanders, latins and men from middle eastern descent.

Fig. 4

Incidence of Male Pattern Baldness in 1,000 White Men by Class and Age*
by O'Tar T. Norwood, MD: 1975

Age
/ --------------------------------------------------------------------------------------------- /

Type
18-29
30-39
40-49
50-59
60-69
70-79
80+
Class 1 110 of 185 men (60%) 60 of 165 men (36%) 55 of 165 men (33%) 45 of 156 men (28%) 29 of 149 men (19%) 18 of 102 men (17%) 12 of 77 men (16%)
Class 2 52 of 185 men (28%) 43 of 165 men (26%) 38 of 165 men (22%) 52 of 156 men (20%) 24 of 149 men (16%) 20 of 102 men (19%) 11 of 77 men (14%)
Class 3 14 of 185 men (6%) 30 of 165 men (18%) 37of 165 men (18%) 34 of 156 men (23%) 22 of 149 men (15%) 16of 102 men (16%) 12 of 77 men (16%)
Class 3v  
(3 of 30 men)**
(15 of 37 men)**
(15 of 34 men)**
(10 of 22 men)**
(7 of 16 men)**
(8 of 12 men)**
Class 4 4 of 185 men (3%) 16 of 165 men(10%) 15 of 165 men (10%) 21 of 156 men (9%) 17 of 149 men (12%) 13 of 102 men (13%) 9 of 77 men (12%)
Class 5 3 of 185 men (2%) 10 of 165 men (6%) 13 of 165 men (8%) 15 of 156 men (10%) 22 of 149 men (15%) 13 of 102 men (13%) 9 of 77 men (12%)
Class 6 2 of 185 men (1%) 4 of 165 men (3%) 7 of 165 men (4%) 10 of 156 men (7%) 19 of 149 men (13%) 11 of 102 men (11%) 10 of 77 men (13%)
Class 7 0 2 of 165 men (1%) 5 of 165 men (3%) 4 of 156 men (3%) 16 of 149 men (10%) 11 of 102 men (11%) 14 of 77 men (17%)
Total 185 (100%) 165 (100%) 165 (100%) 156 (100%) 149 (100%) 102 (100%) 77 (100%)

* Unfortunately, this 1975 study only looked at approx. 1,000 white males and did not include African-Americans, Latinos, Asians, or Pacific Islanders.
** Class 3v men totals are seperate from other totals.

Sources:

  1. Male Pattern Baldness: Classification and Incidence, Southern Medical Journal, O'Tar T. Norwood, MD: Nov. 1975.
  2. How Hair is Lost: DHT & Miniaturization, drshellyfriedman.com, by Dr. Shelly A. Friedman, DO: June, 2012

 


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