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. “Female-pattern hair loss” is the preferred term for hair loss in women.

• Prevalence: Of all postmenopausal women, 37% have some hair loss. Loss of hair at 1–2 months after delivery (telogen effluvium) is common.

• Predominant Age: Older than 50 years. Alopecia areata onset before the age of 30 years.

• Genetics: Androgenic alopecia (male pattern) follows autosomal dominance with incomplete penetrance. Research suggests that the aromatase gene (CYP19A1) may contribute to female hair loss. A genetic role in alopecia areata has been suggested.

Etiology and Pathogenesis

• Causes: Accelerated hair loss may occur at any time if 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 3–9 months, and then the 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, β-blockers, chemotherapeutic agents) may also cause similar hair loss. The relative androgen dominance found in postmenopausal women not undergoing hormone replacement therapy might also cause male-pattern hair loss (temporal balding, androgenic alopecia). Infections with the COVID-19 virus have been associated with telogen effluvium.

• Risk Factors: Pregnancy, delivery, hormonal contraception, scalp disease, family history of baldness, nutritional deprivation, and drug or toxin exposure.

Signs and Symptoms

• Hair loss

• Pruritus, scaling, and broken hairs (tinea)

• Tapered, easily removed hair near the edge of patches (alopecia areata)

Diagnostic Approach