Difference in Terms for Hair Loss

Hello Dr. Rassman, could you tell me what the difference between “thinning hair”, “Hair Loss”, “Miniaturization”, “Low and High Density”?

Also when people say poor nutrition, e.g. anorexia, zinc deficiency etc, causes thinned hair do they mean the shaft diameter of each hair decreases or hair falls out resulting in low density?

Thank You

“Thinning hair” means a person is losing hair (usually hair that is miniaturized – i.e. thinning of the hair shaft) and does not have as much hair bulk as they once had. “Miniaturization” of hair means that a person’s hair shaft is not as thick in one area when compared to another area as it should be in its normal/healthy state. It is normal to have around 10% of miniaturized hairs for people who are not balding that may reflect what we call vellus hairs, present in every follicular unit.

“Density of hair” describes how many hairs are in a given area of scalp. For example an average Caucasian male can have a hair density of 2 hairs per square millimeter of scalp (which translated to about 100,000 hairs on a typical head size). If it is found that the density is 3 hairs per square millimeter, than the person is said to have a high hair density (born with about 150,000 hairs on the head). Hair density is variable and may depend on the ethnicity or race of a person as much as the inheritance patterns. Caucasians are born with an average of 100,000 hair on their heads, Asians about 80,000, and Africans about 60,000. These numbers are just averages and do not necessarily apply to what you may have on your head.