The severity of hair loss can be classified in several
ways. Hair loss in many men, however, follows a
predictable pattern, which was documented by Dr.
James Hamilton and later updated by Dr. O'tar Norwood.
The most common types of hair loss in this progression
are briefly described and illustrated here.
Type I
Normal hairline with no receding or very minimal
recession in the fronto-temporal region
Type II
Hair loss that is more symmetrical, a triangular-shaped
recession develops in the fronto-temporal area.
This recession extends no further than 2cm in
front of an imaginary line drawn between the ears.
Type III
Deeper recessions on the frontal and fronto-temporal
areas occur. There is very sparse hair or no hair
at all. The recession extends further back than
Type II (no further than 2cm past the vertex).
Type III - Vertex
Hair may recede some in the fronto-temporal
areas, but hair loss in this type occurs primarily
at vertex.
Type IV
Hair recedes more in both the frontal and fronto-temporal
areas than in Type III, and hair at the vertex
is very sparse or absent. A band of hair is left
across the top of the head, which connects to
the unaffected areas on the sides of the head.
Type V
Hair loss increases. The band of hair separating
the temporal and vertex areas of the head becomes
smaller and sparser.
Type VI
All that remains of the scalp hair is a narrow
band which begins just in front of the ear and
extends around the back of the scalp (known as
the occipital region).
Type VII
The band of hair is now lost and the two areas
of hair loss meet or merge together.
In addition to these eight main types, there
are Type A variants that affect a small percentage
of the population. They are not depicted here.
However, in all the Type A variants, the front
border of the hairline keeps receding to the rear,
without any concurrent development of hair loss
on the top of the head (vertex). In these variants,
hair loss simply continues to advance from the
front of the scalp to rear.
