Hamilton described 8 types of male pattern baldness occurring in Caucasians. The small percentage of women with male pattern baldness are typed using the same criteria.


Ebling and Rook modified the Hamilton types, with their types II to V corresponding to Hamilton types V to VIII.


Types with Minimal Hair Loss (Not Considered as Bald)


Type I:

(1) thinning or loss of hair without the bilateral recessions along the hairline in the frontoparietal regions

(2) variant A: entire anterior border of the hairline lies high on the forehead


Type II:

(1) bilateral frontoparietal recessions, usually symmetrical and triangular in shape

(2) the recessions do not extend into the area 3 cm anterior to the coronal plane connecting the 2 external auditory meates

(3) the anterior border of the hairline may be receded but the extent is less than the loss in the frontoparietal regions


Type III:

(1) borderline cases

(2) cases where classification is difficult due to scarring or asymmetry

(3) unusual cases of sparseness and thinning


Types Associated with Mild Baldness


Type IV:

(1) bilateral frontotemporal recessions extending further back than type II, less than 3 cm from the coronal line connecting the external auditory meatuses

(2) variant A: hair sparse or lacking as a broad band along the entire anterior border of the hair line

(3) variant "old": an elderly person with loss of some hair over the crown but without extensive hair loss in the frontotemporal or frontal regions


Type V:

(1) sparseness or absence of hair over the crown

(2) frontal recession of the hairline

(3) bilateral frontoparietal recessions approaching close to the coronal line connecting the external auditory meatuses

(4) bands of intact hair separating the denuded crown from the other areas of hair loss


Types Associated with Moderate to Severe Baldness


Type VI:

(1) horseshoe area of alopecia

(2) sparseness or absence of hair over the crown is more extensive than type V

(3) the tonsural region of alopecia over the crown is separated from the frontal and frontoparietal areas of hair loss by a laterally directed (coronal) band of hair which may be incomplete

(4) a small frontal island of hair may be present in the midline

(5) variant A: the peninsular or island of mid-frontal hair is sparse or lost


Type VII:

(1) horseshoe area of alopecia, more extensive than Type VI, with confluence of the hair loss in the frontal, frontoparietal and crown regions

(2) no band or island of mid-frontal hair

(3) there is still at least 1 clump of at least 100 terminal (coarse) hairs in one of the 3 regions


Type VIII:

(1) horseshoe area of alopecia is more extensive than in type VII and extends laterally and posteriorly

(2) terminal (coarse) hairs within the area of alopecia occur as isolated structures without clumps of >= 100 hairs


To read more or access our algorithms and calculators, please log in or register.