Excess Body Hair in Women and Men – Causes and Explanations
Excessive hair growth in women, is a common and difficult to approach problem. There can be excess body hair in women and men on the face, abdomen, breast or pathologically insignificant, either as a sign of a more serious disease.
Distribution and normal hair growth in people is under complex genetic and endocrine control, so there is considerable variability in hair growth among normal men and women. Consequently, abnormal hair growth is difficult to define.
Androgens are major determinants of the distribution of hair in both sexes. Several types of relationships can be defined between hair growth and androgens in normal individuals.
Growth of eyelashes, eyebrows and body hair is not dependent on androgens. Axillary and pubic hair is sensitive to small amounts of androgens; Hair growth in these regions begins when adrenal androgens take control and is approximately equal in men and women.
Hair growth in some regions such as the face, upper pubic triangle, chest and ears, is more typical of men and seems to require higher levels of androgens produced by the testicles. Finally, the scalp hair presents androgenic mediated regression.
Despite similar hormone levels, hair distribution varies between individuals and between different racial and ethnic groups. Whites with black hair and dark complexion of either sex tend to be with more hair than those with blonde or light skin. Asians, American Indians and blacks are on average with less hair than whites. Asians have lower body and facial hair except for axillary and pubic regions and American Indians, moreover, rarely develop alopecia.
Aging is a prerequisite for developing some types of hair.
For example, in men, hair on the trunk and extremities often grow several years after maximum levels of androgens levels were achieved. Conversely, loss of androgens may have no results in loss of normal hair growth in men or complete cancellation of hirsutism in women.
Women in the first trimester of pregnancy usually have an increase in the amount of hair on the face, extremities, and breasts. Menopause is often associated with loss of pubic, axillary and extremities hair, while facial hair growth intensifies in postmenopausal women. These changes can not be explained only by changes in the levels of androgens.
Causes of excess hair
Increased excessive hair growth can be caused by drugs that exert their effects independent of androgens and do not produce virilization. Such drugs include phenytoin, minoxidil, diazoxide, cyclosporine and hexachlorobenzene; hair growth stimulated by these agents is generally defined by a fine hair with body character.
The rapid onset of hair growth, with or without accompanying signs of virilization, suggests a neoplastic source of androgens. Such tumors include adrenal adenoma and carcinoma, ovarian tumors as adrenoblastoma which directly produces androgens and Krukenberg tumors of the ovary
Polycystic ovarian disease
The most common cause of ovarian hyperandrogenism is polycystic ovarian disease.
This disease has a wide spectrum of manifestations that range from discrete hair growth to amenorrhea and virilization. A diagnostic remarkable feature is the installation of pubertal chronic anovulation and hirsutism. Enlarged cystic ovaries, obesity, and amenorrhea (Stein-Leventhal syndrome) are present only in half or less of women with this disorder and should not be present for the diagnosis. Can be the source of androgens excess in the absence of a tumor.
With delayed onset is the most common form of congenital adrenal hyperplasia and was most extensively studied; its incidence in the general population of women with excessive hair and oligomenorrhea is of the order of 1-5%.
In many cases with hirsutism an accurate diagnosis can not be made. The term idiopathic hirsutism is for women with androgen excess signs, but with normal menses, normal sized ovaries without evidence of adrenal or ovarian tumor and normal adrenal function. Slight increase in plasma testosterone and androstenedione is common in women with excessive hair on hand, face, breast, abdomen.