The progression of AGA (male pattern baldness) is generally evaluated by the Norwood-Hamilton Scale. This classification system visually indicates the progression of hair loss by dividing the progression of AGA into the following stages.
Norwood-Hamilton Classification
- Stage 1:
- Little change is seen in the hairline. The frontal hairline is still firm.
- Stage 2:
- The hairline recedes slightly and changes to an M-shape.
- The frontal horns in particular begin to thin.
- Stage 3:
- The frontal hairline recedes further and the forehead becomes wider.
- Mild hair loss may be seen on the top of the head.
- Stage 3 Vertex:
- Clear hair loss is seen on the parietal (whip) area, but frontal recession is similar to Stage 3.
- Stage 4:
- Recession of the frontal area and hair loss on the top of the head become more pronounced.
- Separate frontal and parietal hair loss areas.
- Stage 5:
- Areas of hair loss in the frontal and parietal regions begin to spread and connect.
- The density of hair remaining on the sides and back of the head also begins to decrease.
- Stage 6:
- The frontal and parietal areas of hair loss are completely connected and the majority of the hair is thinning.
- Hair on the sides and back of the head also thins further.
- Stage 7:
- Almost all hair is lost from the top of the head to the sides and back of the head.
- Only a few hairs will remain on the sides and back of the head.
Other progress assessments
- Ludwig classification (evaluation of female pattern baldness):
- A taxonomy to evaluate hair loss primarily in women. It is divided into three levels based on the spread and density of hair loss on the top of the head.
Importance of assessing progress
Assessing the progression of AGA is important in order to select the appropriate treatment. For example, while oral and topical treatments are effective in the early stages, surgical treatment such as hair transplantation may be necessary in more advanced stages. By accurately ascertaining the degree of progression, it is possible to formulate the optimal treatment plan.
Based on these progression classifications, it is recommended that the appropriate treatment be selected in consultation with a physician.
