norwood scale

What Is the Norwood Scale For Male Pattern Balding

What is the Norwood Hamilton Scale?, In the 1975, Dr. Norwood published his famous hair loss classification chart in the Southern Medical Journal. This chart would eventually be known as the Norwood scale 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 of balding, and used more men in his study as a dermatologist in Oklahoma City during the 1970s.

Norwood Scale Types of Receding Hairlines

Hamilton Norwood determined that there were two basic types of receding hairlines or hair loss levels in men with androgenetic alopecia, also knowing has male pattern baldness. The first type including;

  • Regular Type:

This is the predominant type in 97 percent of all 1,000 men that Hamilton studied, and using Norwood scale to log his details. The Regular Type of hair loss shows balding at Norwood 3 and which is noticeable with hair loss at the temples and crown also called the Norwood 3 vertex.

Fig. 1 show Baldness Map pictured below which eventually merge into one continuous and  uninterrupted balding area. The “front to back” stages of male pattern baldness is visible in the “Regular Norwood Chart” below. Also showing in the article seven stages of balding.

Fig. 1, Baldness Map

Regular Type Baldness Map

  • Type A variant:

This is the second type of receding hair loss, constituted the other 3 percent of men in the study. It is distinguished by two major features and two minor features. To get the Type A classification, all the key characteristics must be present. The minor features are not necessary, but are frequently present.

1. The receding hairline’s whole anterior (frontal) line moves posteriorly, leaving no island or peninsula of hair with in mid-frontal area.

2. There is no growth of a balding region on the vertex at the same time.  A bald spot on the vertex does not appear at the same time. Instead, the anterior recession just keeps advancing posteriorly to the vertex (crown).

This isn’t to suggest that Type A males don’t experience crown hair loss; it just happens towards the conclusion of the balding pattern. With either type, one’s eventual balding pattern may be predicted overall general by noting where they’re at, and following the logical progression.

For example, The Norwood 3 generally becomes a Norwood 4, therefore a Norwood 5, and so forth. The type A variant may begin as a 3a vertex, then progress to a 4a, and finally a 5a.

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

“Overall (Figures 4 and 5) standards classify typical sequences throughout the formation 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.”

Dr. Shelly A. Friedman, a specialist in hair transplantation, notes out on his website that a Norwood 2 can thin diffusely and immediately grow into a Norwood 6 or 7. “We call this later process Diffuse Patterned Alopecia.”

Norwood Scale Chart  Fig. 2

Norwood Chart
“Regular Type”
97% of men

Description of Class (6)

Norwood Class 1 Hair Loss Norwood 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 Norwood 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, leaving a slightly higher forehead. Read more to see if  Norwood 2 balding.
Norwood Class 3 Hair Loss Norwood 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 Norwood 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 Norwood 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 of moderately dense hair that extends across the top.”
Norwood Class 5 Hair Loss Norwood 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 Norwood 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 Norwood 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. 3 Type A Variant (below)

Norwood Chart
“Type A Variant”
3% of men

Description of Norwood 6

Criteria for Type  A Variant:
1. The entire anterior (frontal) border of the hairline progresses 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).

Norwood Scale For Male Pattern Balding Norwood 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.
Norwood Scale For Male Pattern Balding Norwood 3a: The area of recession of the fronto-temporal region is almost vertical with the front portion of the ear.
Norwood Scale For Male Pattern Balding Norwood 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.
Norwood Scale For Male Pattern Balding Norwood 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 balding at 40 to 49 age categories, 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.

Incidence of Male Pattern Baldness Stages 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+
Norwood 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%)
Norwood 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%)
Norwood 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%)
Norwood 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)**
Norwood 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%)
Norwood 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%)
Norwood 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%)
Norwood 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 separate from other totals.
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