The phototrichogram helps assess hair growth patterns & treatment responses
The phototrichogram is a clinical tool I generally only use in my research - when I want to understand if a specific treatment is helping or not and quantify just 'how much' it helps. However, sometimes I will use the phototrichogram in patients with complex hair loss patterns. The phototrichogram involves comparison of two small 1 cm x 1 cm areas on the scalp at an interval of three days. On day 1, the hairs in the target 1 cm2 area are clipped to 1 mm and a photograph is taken. 2-3 days later the same areas is evaluated again
What information comes from the phototrichogram?
Several key pieces of information come from the phototrichogram. Hairs that grow over the 2-3 day period are deemed 'anagen' hairs. Hairs that don't grow or elongate are deemed 'telogen' hairs. Hairs that are not present at day 1 but present at day 2-3 are deemed anagen hairs. In addition, hair calibre can also be ascertained. Hairs greater than 40 um are terminal hairs.
In general, the following information can be ascertained from a carefully conduced phototrichogram:
1. hair density
2 terminal hair density
3. vellus hair density
4. anagen hair counts
5. telogen hair counts
6. mean hair thickness
The phototrichogram is a powerful tool. It's not routinely employed in the clinical setting because most patients don't want their hairs clipped (patients come to see me for help with more hair - not less). Nevertheless, the phototrichogram remains a tool I call upon from time to time
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing in hair transplantation. His research has been published in national and international medical journals and presented at scientific meetings around the world. To schedule a hair transplant consultation, please call 416-921-HAIR or toll free 1-855-921-HAIR.