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A new classification of pattern hair loss
that is universal for men and women:
Basic and specific (BASP) classification
Won-Soo Lee, MD, PhD,a Byung In Ro, MD, PhD,b Seung Phil Hong, MD,a Hana Bak, MD,c
Woo-Young Sim, MD, PhD,d Do Won Kim, MD, PhD,e Jang Kyu Park, MD, PhD,f Chull-Wan
Ihm, MD, PhD,g Hee Chul Eun, MD, PhD,h Oh Sang Kwon, MD, PhD,h Gwang Seong
Choi, MD, PhD,i Young Chul Kye, MD, PhD,j Tae Young Yoon, MD, PhD,k Seong-Jin Kim, MD, PhD,l
Hyung Ok Kim, MD, PhD,m Hoon Kang, MD, PhD,m Jawoong Goo, MD,a Seok-Yong Ahn, MD,a
Minjeong Kim, MD,a Soo Young Jeon, MD,a and Tak Heon Oh, MDa
Wonju, Seoul, Daegu, Daejeon, Jeonju, Incheon, Choengju, and Gwangju, Korea
Background: Pattern hair loss (PHL) can be classified into several patterns. Currently, the Hamiltone
Norwood classification system for men and the Ludwig grade system for women are commonly used
to describe patterns of hair loss. However, these pre-existing classifications have some limitations.
Objective: To establish an acceptable, universal, and accurate standard of both male and female pattern
hair loss and to report its use in determining the incidence of PHL.
Methods: We developed a new classification system (BASP classification) and then applied this system to
classify the types of PHL. The BASP classification was based on observed patterns of hair loss. The basic
(BA) types represent the shape of the anterior hairline, and the specific types (SP) represent the density of
hair on distinct areas (frontal and vertex). There are four basic types (L, M, C, and U) and two specific types
(F and V). The final type is decided by the combination of the assigned basic and specific types. Between
November 2004 and June 2005, 2213 Korean subjects, comprised of 1768 males and 445 females, were
classified according to the BASP classification at 13 university dermatologic centers nationwide throughout
South Korea, as a multicenter study of the Korean Hair Research Society.
Results: For both sexes, the majority of patients enrolled in the study were in the third and fourth decade
of life (65.1% of males and 56.68% of females). In males, the older group as well as the younger group in
the study were more likely to have little recession of the frontal hairline (classified as type M1;2) and
diffuse thinning over the top of scalp (type F1;2). The women in the study developed typical female PHL.
Limitations: The subjects of our study were mostly outpatients and some inpatients who complained
about hair loss, not the general population of Korea.
Conclusion: The BASP classification is a new stepwise, systematic, and universal classification system for
PHL, regardless of sex. ( J Am Acad Dermatol 2007;57:37-46.)
From the Department of Dermatology and Institute of Hair and
Cosmetic Medicine, Yonsei University, Wonju College of Medicine,
Wonjua; Department of Dermatology, College of Medicine,
Chung-Ang University, Seoulb; Asan Medical Center,
University of Ulsan College of Medicine, Seoulc; Kyung Hee
University, Seould; Kyungpook National University School of
Medicine, Daegue; Chungnam National University College of
Medicine, Daejeonf; Chonbuk National University Medical
School, Jeonjug; Seoul National University College of Medicine,
Seoulh; Inha University School of Medicine, Incheoni; Korea
University, Seoulj; Chungbuk National University, Choengjuk;
Chonnam National University Medical School, Gwangjul; and
The Catholic University of Korea, Seoul.m
Supported by the 2004 Hair Research Grant of the Korean Dermatological
Association.
Conflicts of interest: None declared.
Reprint requests: Won-Soo Lee, MD, Department of Dermatology,
Yonsei University Wonju College of Medicine, 162 Ilsan-Dong,
Wonju, 220-701, Korea. E-mail: leewonsoo@yonsei.ac.kr.
Published online May 1, 2007.
0190-9622/$32.00
ª 2007 by the American Academy of Dermatology, Inc.
doi:10.1016/j.jaad.2006.12.029
37
Pattern hair loss (PHL) is the most common type
of baldness that occurs after puberty in both sexes.
Patients typically present with the progressive thinning
and shortening of hair in affected areas. Until
recently, various classification methods have been
proposed for describing PHL. In 1950, Beek1 published
the results of classification, using two evolutive
aspects for 1000 white males (frontal and
frontovertical baldness). In the next year, the first
systematic classification of PHL was established by
Hamilton.2 Hamilton subclassified the patterns of
baldness based on frontoparietal and frontal recession
and vertex thinning and then evaluated a large
group of men and women for the presence of
specific patterns of hair loss from the prenatal period
through the tenth decade of life. In 1975, Norwood3
refined Hamilton’s classification by emphasizing
temporofrontal or vertex only subcategories of hair
loss into seven types with a type A variant and
reported the incidence of male pattern baldness at
various ages in 1000 white, adult male subjects. An
additional pattern to the HamiltoneNorwood classification
system (II vertex) was introduced in the
clinical trial of finasteride in male PHL (MPHL).4
In 1992, Savin introduced a classification of MPHL
based entirely on a pictorial depiction of hair density
as derived from midline scalp part width.5-7 Olsen
first proposed assigning separate designations (temporal,
frontal, mid, and vertex) to the areas of the
scalp that bald at different rates in different individuals
with MPHL.8,9 Olsen also proposed an individualized
classification system that assigned a density
scale to each of these designated scalp areas in any
given patient, which was further refined in a later
publication.9,10 Subjects thus classified would have
a TFMV classification (e.g., T3F2M0V3).9
In 1977, Ludwig11 presented quite a different
picture of hair loss in women from that described
by Hamilton. He emphasized preservation of the
frontal fringe despite progressive centrifugal loss
over the top of the scalp and arbitrarily designated
three gradations of hair loss. Recently, Olsen proposed
that frontal accentuation (or the ‘‘Christmas
tree’’ pattern) be considered another pattern of hair
loss in women, which helps to distinguish PHL from
other potential hair-loss mimicries in women.6,9,12
Olsen also devised both a hybrid classification
system for female pattern hair loss (FPHL) that
combined the Ludwig patterns with the Savin hair
density scale, and a classification based on 3 grades
of overall density in either a Ludwig or a frontal
accentuation pattern.6,8
Bouhanna13,14 designed a dynamic, multi-factorial
classification of certain parameters, such as fixed
distances of the face, scalp mobility and thickness,
and covering power of hair, that can be quantified
and computerized for a more precise surgical
approach. Recently, in 2000, Koo et al15 classified
the type of male pattern baldness into 6 types
according to the English alphabetical letter shape of
the bald area. They then studied the prevalence of
MPHL in 1731 Korean men based on their method
and according to age and types of baldness.
Presently, Norwood’s classification for MPHL and
Ludwig’s classification for FPHL are the most commonly
used classification methods for assessing
PHL worldwide.
Although the several aforementioned classification
methods of PHL have been suggested, these
existing classifications have some limitations. The
NorwoodeHamilton classification is too detailed and
is less stepwise in its description, making it difficult
to memorize for common use. NorwoodeHamilton
classification also does not list some peculiar types of
baldness, such as FPHL. Additionally, many women
with MPHL cannot be classified using the Ludwig
classification system.6,9 In addition, for most of these
classification systems, the clinicians must use distinct
methodologies for each gender in order to correctly
classify the pattern. Thus, a more widely accepted,
accurate, and stepwise method of classification for
PHL would be of great benefit.
We therefore devised a new classification system,
named BASP classification, which is comprehensive
and systematic regardless of race and gender. This
classification system was applied to classify patterns
of PHL in Korean patients. Herein we present the
BASP classification method and the data concerning
the incidence of PHL, pertaining to morphological
classification and age.
MATERIALS AND METHODS
The BASP classification
This new classification of PHL was designed
based on the pattern of hair loss, including the shape
of the anterior hairline and the density of hair on the
frontal and vertex areas. There are four basic types
and two specific types. The basic types represent the
shape of the anterior hairline, and the specific types
represent the density of hair on specific areas, which
are frontal and vertex. The final type is decided by
the combination of the basic and specific type. One
of the basic types must be selected, and the specific
type may be selected if it exists. Each of the various
types is subdivided into 3 or 4 grades (subtypes),
according to its severity. Hence, we called this
method BASP classification, composed of the initial
two letters of BAsic and SPecific. Scattered sparse
hairs and islands of hair may persist in the area of
denudation. If the alopecic pattern of a subject
J AM ACAD DERMATOL
JULY 2007
38 Lee et al
cannot be classified by our new method, additional
descriptions may be added.
Basic type
The shape of the anterior hairline is divided into
4 basic types: L, M, C, and U (Fig 1). The basic types
are classified by the English alphabetical letter shape
of the anterior hairline, except L type, which means
‘‘linear.’’ Types M, C, and U are subdivided into 3 or
4 grades, based on severity. The reference points of
classification are set to the original anterior hairline,
the top of vertex (the highest point on the posterior
crown), and the occipital protuberance. We posited
that the patient’s subjective recognition of hair loss is
more significant than the doctor’s identical indicator,
and so we introduced the concept of the original
anterior hairline in our basic type classification. The
original anterior hairline is defined as the anterior
hairline at that time while baldness dose not yet
occur. Therefore, the clinical history of hair loss is
necessary to precisely differentiate among grades.
Type L. No recession is observed along the
anterior border in the frontotemporal region. It
resembles a linear line and usually means that no
hair loss has occurred.
Type M. Recession in the frontotemporal hairline
is more prominent than the mid-anterior hairline.
This type tends to be symmetrical. The hairline
resembles the letter M. Type M is further divided
into 4 subtypes depending on the severity of baldness.
Type M0. The original hairline is preserved and
represents type M. No hair loss has occurred on
clinical history. The subject cannot perceive any
changes in the anterior hairline.
Type M1. Frontotemporal recession extends posteriorly
but not beyond the anterior third of a virtual
line connecting the original hairline and the top of
the vertex.
Type M2. Frontotemporal recession extends further
posteriorly but not beyond the middle third of a
virtual line connecting the original hairline and the
top of the vertex.
Type M3. Frontotemporal recession extends beyond
the middle third section into the posterior third
of the area of a virtual line connecting the original
hairline and the top of the vertex.
Type C. Recession in the mid-anterior hairline is
more prominent than the frontotemporal hairline.
The entire anterior hairline regresses posteriorly in
the shape of half-circle, resembling the letter C.
Type C is further divided into 4 subtypes depending
on the severity of baldness.
Type C0. The original anterior hairline is preserved
and represents type C. No hair loss has
occurred on clinical history.
Type C1. The mid-anterior hairline recedes so that
it lies within the anterior third of the virtual line
connecting the original hairline and the top of the
vertex.
Type C2. The mid-anterior hairline recedes further
so that it lies within the middle third of the virtual
line connecting the original hairline and the top of
the vertex.
Type C3. The mid-anterior hairline recedes further
into the posterior third of the virtual line
connecting the original hairline and the top of the
vertex.
Type U. The anterior hairline recedes posteriorly
beyond the vertex forming a horseshoe shape,
resembling the letter U. Type U is the most severe
pattern of androgenetic alopecia (AGA). Type U
is further divided into three subtypes depending
on the severity of baldness. There is no zero grade
(UO).
Type U1. The entire anterior border of the hairline
lies within the superior third of the virtual line
connecting the vertex and the posterior occipital
protuberance.
Type U2. The entire anterior border of the hairline
lies within the middle third of the virtual line
connecting the vertex and the posterior occipital
protuberance.
Type U3. The entire anterior border of the hairline
lies within the inferior third of the virtual line
connecting the vertex and the posterior occipital
protuberance.
Specific type
The basic types cannot represent the thinning
of hair on the scalp, so additional types representing
the degree of thinning need to be introduced. In
contrast to the basic types, the specific types may be
selectively included when necessary. According to
patterns observed at specific areas, there are two
specific types: F and V. Each specific type is also
subdivided into 3 subtypes, according to severity.
When all the characteristics of both types F and Vare
observed, both specific types should be selected.
Type F. This type only represents a general
decrease in the density of hair over the entire top
of the scalp, regardless of the anterior hairline. It is
usually more marked over the frontal area of the
scalp, as observed in FPHL. This type is similar to
Ludwig’s classification method but only with regard
to thinning hair, and is unrelated to the shape of the
entire hairline.
Type F1. Thinning of the hair on the crown is
perceptible (mild change).
Type F2. Thinning of the hair on the crown is
pronounced (moderate change).
J AM ACAD DERMATOL
VOLUME 57, NUMBER 1
Lee et al 39
Type F3. The hair on the crown is very spare or
absent (severe change).
Type V. The hair around the vertex is notably
sparser. Hair loss is seen more distinctly in the
vertex than in the frontal area. When frontoparietal
and vertex regions of alopecia have become confluent,
type F2;3 should not be confused with type V.
In this case, the differential point is whether the
definite hair loss is primarily on the vertex or not.
Type V1. Thinning of the hair around the vertex
area is perceptible (mild change).
Type V2. Thinning of the hair around the vertex
area is pronounced (moderate change).
Type V3. The hair around the vertex area is very
spare or absent (severe change).
Some examples that were classified using the
BASP method are shown in Fig 2.
Patients
Two thousand two hundred and thirteen
Korean subjects were studied (1768 males and 445
females) and classified according to the previously
described classification. Subjects were mostly outpatients
and some inpatients that complained about
hair loss and were diagnosed with PHL at one of
13 university dermatologic centers nationwide in
South Korea between November 2004 and June
2005, as part of a multi-center study of the Korean
Hair Research Society. This study was approved
by the ethics committee of Korean Hair Research
Society.
We excluded persons who might have had any
hair diseases and had been treated for hair growth
within 6 months before enrollment or who had any
condition influencing hair growth, such as childbirth,
Fig 1. The BASP classification system. Four basic types (L, M, C, and U) and two specific types
(V and F) are used in the BS classification. The basic types represent the shape of the anterior
hairline, and the specific types represent the density of hair on specific areas (frontal and
vertex). The final type is decided by a combination of the basic and specific type. It was named
BASP for the BA in basic type and the SP in specific type.
J AM ACAD DERMATOL
JULY 2007
40 Lee et al
high fever, severe emotional stress, metabolic disease,
or anticancer treatment.
In each subject to whom the above exclusion
criteria did not apply and who consented to the
enrollment, a dermatologist at each center carefully
examined and classified the type of hair loss according
to our new standards. Additionally, a questionnaire
regarding perceptible duration of hair loss,
family history of baldness, previous treatment history
for PHL, chronic disorders, and drug history was also
completed by each subject.
Digital photographs were then taken in sequence
with 6 standardized views. These views included: (1)
frontal without tilt; (2) 458 tilt and (3) nearly 908 tilt to
the front side of the head; (4) anterior view wearing
a thin hair band to observe the anterior hairline; and
(5 and 6) bilateral 908 side views. In addition to these
6 views, a posterior view of the scalp was taken if
the subject was classified as type U. A representative
example of the photographs taken is shown in Fig 3.
Accuracy and ease of use
To test the accuracy of this method of classification,
verification tests were performed. Three dermatologists
at the department of dermatology at the
Yonsei University Wonju College of Medicine, who
were well trained to use the new method, classified
the baldness patterns of 100 subjects by inspecting
the clinical digital photographs of the scalp. The
classification accuracy was then evaluated by comparison
of the three results.
In order to prove the easy-to-use nature of the
new system, the photographs of scalps, which were
accorded more than two of three results among the
same 100 subjects mentioned above, were assessed
by two independent general physicians at Wonju
Christian Hospital. These physicians were trained to
use our method for only 15 minutes immediately
before the test. The classification results of the two
general physicians were then compared with the
results obtained identically by more than two of the
three dermatologists mentioned above.
RESULTS
Age and sex distribution of pattern hair loss
The male subjects totaled 1768 individuals, a
number four times as great as the 445 female
subjects. The majority of patients were in their third
and fourth decade of life in both sexes, encompassing
1150 of male (65.1%) and 252 of female (56.68%)
subjects. The number of subjects decreased steadily
over the fourth and fifth decades of life.
Fig 2. Examples of BASP classification of pattern hair loss. A, A 32-year-old male, LF2 type.
B, A 49-year-old male, M2F2 type. C, A 59-year-old male, M1V3F2 type. D, A 27-year-old
male, C1V2F1 type. E, A 48-year-old male, U2 type. F, A 45-year-old female, LF2 type.
G, A 58-year-old female, C1F3 type. H, A 32-year-old female, M1F1 type.
J AM ACAD DERMATOL
VOLUME 57, NUMBER 1
Lee et al 41
Incidence of basic type by age group
In men, regardless of age, 1434 men of the 1768
subjects were classified as type M, accounting for
81.1% of cases and being the most common basic
type. Among the subtypes and according to the
severity of baldness, the majority in subjects below
50 years of age were classified as type M1, whereas
most subjects over the age of 50 were classified as
type M2 (Table I). Type L (9.3%) tended to decrease
with age, but types C (5.8%) and U (3.8%) tended to
increase.
In women, type L showed the highest frequency
in the all age groups, accounting for 210 (47.2%) of
445 female subjects. Regardless of age, types M, C,
and U followed in order, with 121 women (27.2%),
111 women (25.0%), and 3 women (0.6%) of the 445
subjects, respectively. Type C0 was the second most
common subtype in female subjects between the
Fig 3. Six standard views of the clinical photograph. Frontal view without tilt (A), a 458 tilt to
the front side of the head (B), a nearly 908 tilt (C), an anterior view (D), and bilateral 908 side
views (E and F) to observe the anterior hairline of a patient wearing a thin hair band. The hair
loss pattern of this patient is classified as M2F1 type.
Table I. Distribution of basic type in males by age group
No. (%) by age (y)
Type #19 20-29 30-39 40-49 50-59 60-69 $70 Total
L L 10 (20.4) 92 (12.0) 30 (7. 11 (5. 8 (4.7) 9 (7.3) 4 (4.9) 164
M M0 12 (24.5) 100 (13.1) 22 (5.7) 6 (3.1) 2 (1.2) 1 (0. 2 (2.4) 145
M1 19 (38. 351 (45.9) 155 (40.3) 58 (30.4) 50 (29.1) 27 (21. 23 (28.0) 683
M2 4 (8.2) 170 (22.2) 120 (31.2) 54 (28.3) 55 (32.0) 44 (35.5) 28 (34.1) 475
M3 2 (4.1) 28 (3.7) 28 (7.3) 23 (12.0) 24 (14.0) 17 (13.7) 9 (11.0) 131
C C0 — 10 (1.3) 1 (0.3) 1 (0.5) 0 (0.0) 1 (0. 1 (1.2) 14
C1 1 (2.0) 3 (0.4) 11 (2.9) 2 (1.0) 3 (1.7) 3 (2.4) — 23
C2 — 7 (0.9) 6 (1.6) 4 (2.1) 3 (1.7) 3 (2.4) — 23
C3 — 1 (0.1) 6 (1.6) 18 (9.4) 6 (3.9) 8 (33.3) 4 (4.9) 43
C 1 (2.0) 21 (2.7) 24 (6.2) 25 (13.1) 12 (7.0) 15 (12.1) 5 (6.1) 103
U U1 1 (2.0) — 1 (0.3) 6 (3.1) 7 (4.1) 3 (2.4) 7 (8.5) 25
U2 — 2 (0.3) 4 (1.0) 6 (3.1) 8 (4.7) 4 (3.2) 1 (1.2) 25
U3 — 1 (0.1) 1 (0.3) 2 (1.0) 6 (3.9) 4 (3.2) 3 (3.7) 17
U 1 (2.0) 3 (0.4) 6 (1.6) 14 (7.3) 21 (12.2) 11 (8.9) 11 (13.4) 67
Total (%) 49 (100) 765 (100) 385 (100) 191 (100) 172 (100) 124 (100) 82 (100) 1768
Types are divided into grades as indicated in the text.
C, Hair loss pattern shaped like the letter C; L, linear; M, hair loss pattern shaped like the letter M; U, hair loss pattern shaped like the letter U.
J AM ACAD DERMATOL
JULY 2007
42 Lee et al
second and fourth decade of life, and its incidence
decreased with age (Table II).
Incidence of specific type by age group
In men, type F was observed in 42.4% (749/1768)
of male subjects, and type V was observed in 19.8%
(350/1768). The grade of both types seemed to
increase slightly with age (Fig 4, A and B). In women,
type F was observed in 70.6% (314/445) of female
subjects with AGA (Fig 5). The incidence of type V
(6.3%) is not shown.
Accuracy and ease of use tests
A comparison of the results of the classification
performed by three experienced dermatologists is
shown in the Table III. The accuracy rate of our
classification was defined as the sum of the accordance
rate of more than two of three results. The
accuracy rate was 96% in basic type classifications,
94% in specific type classifications, and 83% in final
type classifications. The accordance rates between
the classification result, which was accorded more
than two of three expert dermatologist’s classifications
and two amateur general physicians’ classifications,
were approximately 80% in all basic, specific,
and final types.
Table II. Distribution of basic type in females by age group
No. (%) by age (y)
Type #19 20-29 30-39 40-49 50-59 60-69 $70 Total
L L 8 (38.1) 69 (46.3) 54 (50.9) 30 (46.2) 24 (53.3) 19 (46.3) 6 (54.5) 210
M M0 2 (9.5) 16 (11.0) 10 (9.4) 12 (18.5) 5 (11.1) 9 (22.0) 1 (9.1) 55
M1 3 (14.3) 13 (8.9) 6 (5.7) 13 (20.0) 7 (15.6) 5 (12.2) 3 (27.3) 50
M2 — 1 (0.7) 3 (2. 5 (7.7) — 2 (4.9) 1 (9.1) 12
M3 2 (9.5) 2 (1.4) — — — — — 4
C C0 5 (23. 35 (24.0) 21 (19. 9 (13. 4 (8.9) 3 (7.3) — 77
C1 1 (4. 8 (5.5) 11 (10.4) 4 (6.2) 2 (4.4) 3 (7.3) — 29
C2 — — — 1 (1.5) 3 (6.7) — — 4
C3 — — — 1 (1.5) — — — 1
U U1 — — 1 (0.9) — — — — 1
U2 — — — — — — — 0
U3 — 2 (1.4) — — — — — 2
Total (%) 21 (100) 146 (100) 106 (100) 65 (100) 45 (100) 41 (100) 11 (100) 445
Types are divided into grades as indicated in the text.
C, Hair loss pattern shaped like the letter C; L, linear; M, hair loss pattern shaped like the letter M; U, hair loss pattern shaped like the letter U.
Fig 4. Distribution of degrees of the specific types in
male by age group. A, Type V; type V was observed in
approximately 20% of male subjects. Increasing with age,
type V1 tended to decrease, but the proportion of types V2
and V3 tended to increase. B, Type F; type F was steadily
observed in approximately 40% of male subjects. The
proportion of type F1 tended to decrease with increasing
age, but the proportion of types F2 and F3 tended to
increase.
Fig 5. Distribution of degrees of type F in female by age
group. The proportion of type F increased with age,
especially types F1 and F2, between the second and the
sixth decade of life.
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VOLUME 57, NUMBER 1
Lee et al 43
DISCUSSION
The term AGA was coined by Orentreich16 in
1960, but the same condition in men has been
termed ‘‘male pattern alopecia,’’ ‘‘common baldness,’’
‘‘male pattern baldness,’’ and ‘‘male pattern
hair loss.’’8,17,18 Because androgen dependence and
hereditary factors are less obvious in affected women
than in affected men, the termPHL, which has a more
broad concept, is more preferable for women than
the term AGA.8,9 Therefore, we titled this article
using the termPHL, which can be reasonably applied
to both sexes.
There are also racial differences in the prevalence
and patterns of PHL.2,19-21 In a previous study, a
female pattern was observed in 11.1% of Korean
males with AGA, which is higher than that found in
white males.20 In the current study, a female pattern
(type F) accounted for approximately 37% in men,
which was more frequent than expected. The prevalence
of male pattern baldness accounted for 14.1%
in Korean males and 38.5% in Thai males; in white
males, it accounted for 46.0%.3,20,21 In addition,
Japanese men develop AGA approximately one
decade later than whites, and the prevalence is 1.4-
fold lower in each decade of life.22 Therefore, Asian
men with PHL are disposed to have different aspects
from those of whites.
PHL in females occurs much more frequently than
is generally believed. Price23 noted that the incidence
is the same as in males. Norwood24 also stated
that female AGA affects up to 30% of older women.
In addition, some females may develop balding in
various patterns similar to those of males.12 PHL
clearly was a stressful experience for both sexes, but
it was substantially more distressing for women,
so these women may need more thoughtful evaluation
and management.25 Accordingly, an additional
detailed classification system for women must be
developed as a necessity. If a unified classification
method for both sexes is developed, it would be
most beneficial.
As the results of this research show, the majority
of individuals that visited the dermatologic clinic for
hair loss were young adults in the third and fourth
decade of life and not older. For such patients,
a more stepwise classification is required for the
proper identification of both a concretely defined
early stage and the steps that further describe the
process of balding.
Table III. The results of accuracy and ease of use tests
Basic type Specific type Final type
Factor No. % No. % No. %
Accuracy*
Three all 60/100 94.0% 61/100 96.0% 41/100 83.0%
Two 34/100 35/100 42/100
None 6/100 6.0% 4/100 4.0% 17/100 17.0%
Ease of usey
GP1 79/94 84.0% 76/96 79.2% 59/83 71.1%
GP2 79/94 84.0% 84/96 87.5% 64/83 77.1%
GP, General physician; three all, three results accorded; two, two of three results accorded; none, none of three accorded.
*Three dermatologists classified the baldness patterns of 100 subjects by inspecting the clinical digital photographs of the scalp. The
classification accuracy was then evaluated by comparison of the three results. The accuracy rate was defined as the sum of the accordance
rate of more than two of three results.
yThe classification results of the two general physicians were then compared with the classification result obtained identically by more than
two of the three dermatologists mentioned above.
Table IV. Correlation between the representative
classifications and BASP classification of pattern
hair loss
Male classification
BASP classification
Norwood Basic Specific Final
I L, M0;1, C0;1 — L, M0;1, C0;1
II M1;2 — M1;2
IIa C1;2 — C1;2
III M2;3 — M2;3
III vertex M2;3 V1 M2;3 V1
IIIa C2 — C2
IV M2;3 V2;3 M2;3 V2;3
IVa C2;3 — C2;3
V M3, C3 V3 M3V3, C3V3
Va C3 — C3
VI C3, U1 V3 C3V3, U1
VII U2;3 — U2;3
Female
classification
Ludwig
Grade I L, M0, C0 F1 LF1, M0F1, C0F1
Grade II L, M0, C0 F2 LF2, M0F2, C0F2
Grade III L, M0, C0 F3 LF3, M0F3, C0F3
J AM ACAD DERMATOL
JULY 2007
44 Lee et al
In the BASP classification system, the PHL was
categorized into basic and specific types. During the
balding process, the recession of the anterior hairline,
represented with the basic type classification,
relatively corresponds with the thinning of hair on
the crown and vertex. However, because the degree
of recession might be out of accordance with the
density of hair in many individuals, the separation of
both characteristics is important for proper classification.
Furthermore, the combination of two features
of PHL is better suited to more thorough description
of the baldness phenotypes. This fundamental idea
that the viewer can separately match pattern or area
with density is similar to the regional scalp hair
density method by Olsen9 using the area of the scalp
assigned a letter (T, F, M, and V) and the density
of hair in that region of the scalp. But the BASP
classification system is different from Olsen’s system
in that our method focuses on the shape of anterior
hairline (basic type), and is a simpler method with a
density scale of 0 to 3. We also adopted basic types
and specific type V as new guidelines by modifying
Hamilton’s,2 Norwood’s,3 and Koo et al’s15 suggested
classifications, and specific type F from Ludwig’s11
proposal. The correlation between the representative
classifications and our new classification of
pattern baldness is shown in Table IV.
According to the severity of the phenotype, we
also subclassified both the basic and specific types
into subtypes in order to generate a more stepwise
and systematic classification method. We can describe
patterns of hair loss in detail using the new
method, and, thus estimate both the further extent of
hair loss and the therapeutic response to a certain
therapy.
The accuracy of any method of classification
based on inspection can be criticized for any procedure
based on subjective judgment. In order to check
the accuracy of the BASP classification, we carried
out a verifying test which was different from
Hamiliton’s test method. Although the accuracy
rate of the BASP method was lower than that
obtained by Hamilton, it should be noted that the
BASP classification accuracy rate was more than 80%
and, when analyzed separately by the basic and by
the specific type, reached 94% in basic type and 96%
in specific type. If the examiner classified the real
scalp of a subject, more accurate results may be
expected.
Another test to prove the easy-to-use format of the
BASP classification system was performed. In spite of
a study period of only 15 minutes, the accordance
rates accounted for 77.1% and 71.1% in the final type.
This result shows that the BASP classification is easy
to learn and practice. Because the BASP classification
is easy to memorize, owing to its stepwise and
systematical characteristics, there is no difficulty in
applying the system clinically. Because the new
classification can also be applied to both sexes, it is
more universal than previously used methods.
Although the BASP classification may seem to
be complex as compared with other classification
methods, we think that the BASP classification is not
complicated or difficult and has many advantages for
describing PHL. In an advanced stage of baldness,
confusion between types F and type V may occur.
But because scalps with advanced baldness tend to
appear similar and all two types exist in fact, such
confusion is understandably possible, and careful
observation is required. The subjects of this study
were mostly outpatients and some inpatients who
complained about hair loss. Therefore, our data does
not indicate the prevalence and types of PHL in the
general population of Korea. However, the results of
this study do represent the tendency of people with
various types of hair loss to visit the dermatologic
clinic.
In conclusion, we expect that the BASP classification
may prove particularly useful in communicating
the exact amount and distribution of hair loss in
those with PHL. Although there are, of course, some
shortcomings in our new method, it is easily available,
stepwise, and comprehensive regardless of
race or sex. Future studies, such as of the incidence
of PHL in the general population and of the longterm
progression, can be performed using the new
system.
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46 Lee et al |
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