Inservice Exam - 2005
Cosmetic Hair

Which of the following terms represents the primary active phase of hair growth?

(A) Anagen
(B) Anaphase
(C) Metaphase
(D) Telogen
(E) Telophase


The correct response is Option A.

Normal hair growth involves two primary phases. The active phase, anagen, is the phase of hair growth. In this phase, which can last three to five years, approximately 85% of hair follicles produce hair. The resting phase, telogen, heralds the loss of the hair shaft and affects approximately 15% of hair follicles at any given time. Balding occurs when the anagen phase is shortened and the telogen phase is prolonged.

Anaphase, metaphase, and telophase are all phases in cell division and the replication of deoxyribonucleic acid. They are not specifically related to hair growth.

References:
1. Orentreich N. Advances in Biology of Skin. Vol 9. New York: Pergamon Press; 1969.
2. Orentreich N, Durr NP. Biology of scalp hair growth. Clin Plast Surg. 1982;9:197.




Which of the following is the most common cause of male pattern baldness?

(A) Cyclical hair loss
(B) Decreased plasma androgen level
(C) Decreased plasma testosterone level
(D) Increased plasma estrogen level
(E) Inheritance


The correct response is Option E.


The only cause of male pattern baldness is inheritance of an X-linked autosomal dominant gene. Male pattern baldness is also influenced by other minor genetic factors. The pattern and timing of baldness and the age of onset of hair loss are influenced primarily by all of these genetic factors.


Cyclical hair loss is characteristic of normal hair growth. Plasma androgen, testosterone, and estrogen levels have not been shown to influence the rate or timing of baldness. However, increased levels of 5_-reductase have been an isolated finding in the hair follicles of balding patients.

References:
1. Ayres S. Hair transplantation. In: Epstein E, Epstein E Jr, eds. Skin Surgery. 6th ed. Philadelphia: WB Saunders; 1987.
2. Orentreich N, Durr NP. Biology of scalp hair growth. Clin Plast Surg. 1982;9:197.