Chapter 19: Male Pattern Hair Loss

INTRODUCTION

Male pattern hair loss classically presents with bitemporal hair loss that progresses to the loss of hair on the vertex, frontal, and temporal scalp. Parietal and occipital hairs are usually unaffected. It is a nonscarring form of alopecia that occurs in genetically susceptible males. The gradual involuntary loss of hair does change the natural frame hair provides around our face. The gradual loss of hair resulting in an involuntary change in appearance creates varying degree of emotional and psychological stress. Many men seek treatment for male pattern hair loss because of unhappiness with its cosmetic appearance and association with aging.

EPIDEMIOLOGY

Incidence: 30% of males older than 30 years; more than half of males older than 50 years.

Age: begins after puberty.

Precipitating factors: polygenetic inherited predisposition. No diagnostic tests exist to determine the etiology and natural progression.

PATHOGENESIS

The precise pathophysiology remains unknown. This process is believed to result from both a polygenetic inherited susceptibility as well as androgenic stimulation. The most important androgen in this process is dihydrotestosterone.

There is a diminution in the size of affected terminal follicles that regress to become vellus follicles that eventually disappear. There is an increase in telogen hairs and a decrease in anagen hairs.

PHYSICAL EXAMINATION AND NATURAL PROGRESSION

Typically, frontal and temporal hair loss/thinning is present first. This begins in puberty and progresses over decades. The rate and extent of hair loss varies from individual to individual. Some progress to complete baldness in early 20s and others gradually thin over decades.

DIFFERENTIAL DIAGNOSIS

In males, the pattern of hair loss is characteristic suggesting no other diagnoses.

LABORATORY EXAMINATION

In males, no laboratory workup is typically required.

MEDICAL THERAPY

Key Consultative Questions

• Age of onset

• Rate of hair loss

• Past medical history

• Medications used to date and success of therapy

• Patient expectation of any medical or surgical therapy

FDA-Approved Medical Therapy (Table 19.1)