Hair loss in men assumes many different forms, to the point that a near universal hair loss classification for men, known as the “Norwood Classification” was devised in 1975 by Dr. Norwood. For instance, the first class does not include any actual, balding. Instead, it represents an adolescent hair line that sits on the upper brow crease. In the second class, some temporal recession begins to form as the scalp makes the transition from a juvenile to an adult hairline. However, the state of balding has still not occurred. In the third class, the temporal recession deepens, as the primary stage of hair loss in men begins. In the fourth class, the vertex begins to enlargen, and subsequent frontal hair loss occurs. However, there is still a band of hair that dichotomizes the vertex and the front across the mid-scalp. In the fifth class the hair bridge that divides the crown and the front begins to degrade, and bald areas in the crown and the front continue to expand.
Furthermore, in the sixth class the connecting hair bridge completely disappears, leaving behind a singular and profuse bald area on the top and front of the scalp. However, much of the hair found on the sides of the scalp remain. In the final class hair loss is extensive and noticeable throughout the scalp, with only wreaths or tufts of hair remaining either on the sides or the back of the scalp. As can be seen, male pattern baldness tends to follow a progressive pattern of hair loss. However, the causes of hair loss in men are numerous including genetic and hormonal factors, as well as certain diseases, drugs, and aging. In addition, while androgenic alopecia-or male pattern baldness-is the most common form of baldness, affecting almost 80% of the male population by the time they reach 70, there are also other, less common forms of male baldness.
For instance, diffuse patterned alopecia is an androgenetic type of hair loss that is characterized by hair thinning in the crown, front, and top of the scalp, leaving behind a stable and permanent zone. As for diffuse unpatterned alopecia, it is not characterized by a permanent, stable zone, and results in a horseshoe pattern that closely resembles the attributes of a man with class 7 hair loss. The difference between the two, however, is that the lower hair density on the sides and the back, caused by diffuse unpatterned alopecia, may cause the horseshoe to look transparent. In sum, the difference between diffuse patterned and unpatterned alopecia is fundamental, as patients who suffer from diffuse patterned alopecia are usually good candidates for hair transplants, as they tend to have a stable hair zone for harvesting.