|
The
Norwood male pattern baldness classification system
Male pattern baldness is often diagnosed with the help of a classification
system using diagrammatic representations of progressively more
extensive hair loss. Originally designed by Hamilton in the 1950s
the pattern baldness classification system was modified to its current
form by Norwood in the 1970s. Norwood also added grades IIIa, III
vertex, IVa and Va to Hamilton's original classification scale.
There are now seven recognized categories of male androgenetic
alopecia along with various subtypes based on Norwood's classification
system. Frequently when consulting with a dermatologist the diagnosis
of androgenetic alopecia will be made in reference to the classification
and you will be given your subclass such as “type III” or similar.
These classification scales are used extensively in monitoring treatment
trials.
Norwood's basic scale is described and illustrated below. Norwood's
variant scale is described elsewhere.
Type I. Minimal or no recession of the hair line.
Type II. Triangular, usually symmetrical, areas of recession at
the frontotemporal hair line.
Type III. This represents the minimal extent of hair loss sufficient
to be considered as baldness according to Norwood. Most type III
scalps have deep symmetrical recession at the temples that are bare
or only sparsely covered by hair.
Type III vertex. In this presentation, the hair loss is primarily
from the vertex with limited recession of the frontotemporal hair
line that does not exceed the degree of recession seen in type III..
Type IV. The frontotemporal recession is more severe than in type
III. There is sparse hair or no hair on the vertex. The two areas
of hair loss are seperated by a band of moderately dense hair that
extends across the top. This band connects with the fully haired
fringe on the sides of the scalp. Type IV is distinguished from
type III vertex in which the loss is primarily from the vertex.
Type V. The vertex hair loss region is still seperated from the
frontotemporal region but it is less distinct. The band of hair
across the crown is narrower and sparser. The vertex and frontotemporal
regions of hair loss are bigger. Viewed from above, types V, VI,
and VII are all characterized by suviving hair on the sides and
back of the scalp forming a distinct horseshoe shape.
Type VI. The bridge of hair that crossed the crown is now gone
with only sprase hair remaining. The fronttemporal and vertex regions
are now joined together and the extent of hair loss is greater.
Type VII. The most severe form of hair loss presents as extensive
loss. A narrow band of of hair in a horseshoe shaps survives on
the sides and back of the scalp. This hair is usually not dense
and may be quite fine. The hair is alos sparse on the nape of the
neck and in a semi circle over both ears.
The
Norwood male pattern baldness classification system references
- Norwood
OT. Male pattern baldness: classification and incidence. South
Med J. 1975 Nov;68(11):1359-65.
- Norwood OT. Hair Transplant Surgery. Charles
C Thomas Publishers, Springfield IL, USA, 1973. ISBN 0-398-02892-3
|
