Hamilton-Norwood scale - Male Alopecia
This scale classifies baldness into the following types:
- Type I: Negligible or scarce hair loss in the frontal line.
- Type II: Hair loss in the temporal area. The hairline begins to recede.
- Type III: Hair loss, especially in the crown area. It is the minimum level to consider the existence of baldness.
- Type IV: The hairless area on the crown is enlarged. Hair loss in the frontal area is higher than that of phase III. A hair band clearly separates the two bald areas.
- Type V: The crown and frontal areas are separated only by a narrow region. Seen from above, the area that still has hair draws the shape of a horseshoe (also in types VI and VII).
- Type VI: The anterior and posterior areas without hair are united, and the area affected is widened.
- Type VII: In this stage only a narrow portion of the original hair remains, spread over the ears and meeting at the nape.
Ludwig Scale - Female Alopecia
Female Alopecia Scale - Ludwig System:
- Type I: It shows a perceptible although diffuse hair loss in the crown.
- Type II: An increase of hair loss can be seen in the same area.
- Type III: Includes the hair loss of type I and II, but also the initial hair loss in the fronto-temporal line.
- Type IV: Shows a continuation of that diffuse loss and fronto-temporal recession.
- Type V: There is a complete loss of scalp hair that resembles the male baldness pattern.
Types III, IV, and V are very unusual cases and typically happen to menopausal women.