Baldness

I

Introduction

Baldness, or alopecia, a partial or complete loss of hair, primarily affecting the scalp. Baldness may spread over the entire head, or it may occur only in spots. Known causes of baldness include hereditary factors, aging, diseases affecting the entire body, scalp disorders, ionizing radiation, and reaction to drugs.

II

Hereditary Baldness

In hereditary baldness, the hair follicles and oil glands in the scalp deteriorate and the hair gradually becomes thinner until only a few strands of fine, downy hair remain. The most common form of inherited baldness is male pattern baldness, which spreads evenly, usually beginning with a partial loss of hair on the upper temples and on the crown of the head. This condition appears most frequently in men over 30 years old, although in some cases it may occur prematurely, even as early as the mid-teens. This form of heredity baldness may be due in part to the hormonal changes that accompany the aging process.

Women become bald less often than men, but they carry the genes that determine pattern baldness and pass them on to their children. When inherited female pattern baldness does occur, it normally affects menopausal women—that is, women around the ages of 45 to 50 years old, suggesting a link to hormonal changes.

III

Diseases That Cause Baldness

Several diseases, particularly those characterized by prolonged high fevers, may cause baldness. Typhoid fever or scarlet fever can cause sudden loss of hair from the head or entire body. Gradual loss of hair may be caused by malnutrition, disorders of the endocrine system, drug poisoning, and other diseases. Alopecia universalis causes a permanent and total loss of hair over the entire body including the eyebrows and eyelashes. The cause of alopecia universalis is unknown.

---

---

Fungal infections like ringworm, severe bacterial infections, tuberculosis ulcers, and burns may also result in loss of hair in affected areas. Early treatment of some infections, particularly seborrheic dermatitis—chronic inflammation of the skin that also causes dandruff—may succeed in preventing hair loss from the scalp.

IV

Other Causes of Baldness

Individuals who have been exposed to significant doses of ionizing radiation, as from the explosion of nuclear weapons, tend to suffer from temporary baldness. Exposure to ionizing radiation from X-ray machines and other devices used to treat cancer may also cause temporary baldness. In addition, chemotherapy for cancer, which tends to destroy all rapidly dividing cells, may cause temporary total baldness because of its effect on hair follicles, which contain some of the most active cells in the body.