Chapter 26 Hair Loss
INTRODUCTION
Description: Patients often experience hair loss in the early stages of pregnancy, in the immediate postpartum period, or in the postmenopausal years. For some this may be of sufficient volume to cause concern or cosmetic problems.
Prevalence: Of postmenopausal women, 37% have some hair loss. Loss of hair 1 to 2 months after delivery (telogen effluvium) is common.
ETIOLOGY AND PATHOGENESIS
Causes: Accelerated hair loss may come about any time there is an abrupt change in hormonal patterns and is the result of a higher number of hair follicles entering into the resting, or telogen, phase of hair growth. Hair follicles have cycles of growth (anagen), followed by a resting phase (telogen) of 3 to 9 months, and then resumption of normal growth. Alterations in hormones may induce an increased number of follicles to enter telogen. If this is the situation, the lost hair will be regained in time. Stress and some medications (anticoagulants, retinoids, beta blockers, chemotherapeutic agents) may also cause similar hair loss. The relative androgen dominance found in postmenopausal women not receiving hormone replacement therapy might also cause male pattern hair loss (temporal balding, androgenic alopecia).
