Typical male and female patterned baldness usually starts with the thinning of hair shafts. This decrease in the size of individual hair shafts is called miniaturization. The miniaturization of scalp hair during male or female patterned hair loss is usually followed by obvious baldness when scalp hair becomes invisible to the naked eye. While microscopic evaluation of the hair and the scalp helps to determine the miniaturization rate of human hair, the beginning of balding in patients is normally not too obvious unless significant miniaturization is present. In general, baldness is not apparent on a patient until more than 70% of the hair has become miniaturized. Because of this fact, a miniaturization study is a vital step in the hair loss evaluation of a patient and could be a great predictor for future patterns and classes of balding. Patients in the active phase of hair loss usually show significant hair miniaturization.
During a miniaturization study, we map the patient’s scalp with a microscope before starting them on medical treatments or planning for a hair transplant procedure.
Younger patients who show significant miniaturization are more likely to lose their vulnerable hair following their hair transplant surgery as a result of the stress of the surgical procedure on their hair follicles. This hair loss is known as shock loss and happens less frequently in patients who have a much smaller amount of hair miniaturization as well as patients who have end stage balding with no preexisting visible hair in the transplanted area. We regularly perform a miniaturization study while our patients are on medical hair loss treatment with finasteride or minoxidil to gauge the effectiveness of the treatment plan. Patients who are balding, and are considering hair transplant options, should also have their hair mapped for miniaturization in order to determine the state of their current hair loss and to predict the future pattern. Combined with a family history of baldness, the miniaturization study is one of the most reliable methods to determine the future pattern of hair loss. The study also helps us formulate a master plan including both surgical hair restoration to cover bald areas and medications to prevent balding on anticipated balding areas.
Normal and Abnormal Miniaturization Study
It’s important to note that having up to 20% miniaturized hair in any given area could be normal in most individuals and could be explained by the recycling of hair follicles. Every scalp hair spends most of the time in the growth phase and a small portion of time in the resting phase. These are the main phases in human scalp hair growth:
- Growth phase (Anagen) which lasts between 1 to 6 years.
- Resting phase (Telogen) which lasts around 4 to 6 weeks.
When patients lose one hair to the telogen phase, hair follicle go to sleep and the hair shaft falls. This is always followed by another hair growing from the same follicle. The newly growing hair is usually represented by a very small hair, which should not be mistaken for miniaturized hair due to the balding process. Patients with hair miniaturization of over 20% in any area of the scalp are likely to lose more hair or become completely bald in those areas. Larger miniaturization numbers can represent more active hair loss as well as further balding in the future. Patients who have significant miniaturization could take finasteride to prevent or slow down the process of the hair loss. These patients should be evaluated on a regular basis and with repeated miniaturization studies to evaluate their response to the medication and to adjust the course of treatment if necessary.