Causes of Hirsutism

Hirsutism is a condition with excess growth of hair in a male pattern. This male pattern of hair distribution indicates growth of hair in places like chest, areola, face, lower abdomen, upper back, lower back, buttocks, inner thighs and external genitalia. It is generally caused by excess male sex hormone - androgens, and the causes of hirsutism include any condition which increases the blood level of androgens.

The causes of hirsutism can be broadly classified in to five categories:
  • Hormone system related 
  • Tumor related 
  • Drugs
  • Miscellaneous 
  • Unknown

Hormone system related causes of hirsutism:

The hormone or the endocrine system is a delicately managed system with wonderful feedback controlled by the pituitary gland and the hypothalamus of the brain. Secretion of androgens is also under the control of this system. Any perturbation in it can change the blood levels of the androgens.
Androgens are normally secreted by the adrenals and the ovaries in women.

The causes of hirsutism under this category include:
  • Cushing's syndrome - defined as excess secretion of steroids including androgens
  • Congenital adrenal hyperplasia - An enzyme deficiency leading to excess production of androgen
  • Acromegaly - Excess growth hormone and insulin resistance
  • Hyperprolactinemia - Increased prolactin levels
  • Hypothyroidism - There is a decrease in the thyroid hormone levels
  • Polycystic ovarian disease - This is an ovarian disease with multiple cysts and increased blood androgen levels
  • Obesity

Tumor related causes of hirsutism:

Tumores of the ovaries and the adrenal glands secrete excess hormones including androgen.
The causes of hirsutism under this category include:
  • Ovarian tumors
  • Arrhenoblastoma
  • Gonadoblastomas
  • Lipoid cell tumors
  • Dysgerminoma
  • Brenner's tumor
  • Granulosa -theca cell tumors
  • Adrenal tumors
  • Adrenal adenoma
  • Adrenal carcinoma

Drugs causing hirsutism:

There are certain drugs which increase body hair. The distribution of excess can be limited to androgen sensitive areas or both androgen and non androgen responsible  areas. A condition when excess hair also occurs in non androgen sensitive areas is called hypertrichosis.

Drugs causing hirsutism and hypertrichosis are:
  • Minoxidil
  • Phenytoin
  • Cyclosporine
  • Diazoxide
  • Androgens
  • Oral contraceptives  - containing progesterone
  • Penicillamine
  • Heavy metals
  • Acetazolamide

Miscellaneous causes of hirsutism:

This category consists of diverse causes which cannot be grouped under other categories.

Causes of hirsutism under this category include:
  • Syndromes of excessive insulin resistance
  • Functional adrenal hyperandrogenism
  • Hypereactio luteinalis of pregnancy - transient increase in androgen levels during pregnancy
  • Thecoma of pregnancy - Transient androgen secreting tumor during pregnancy
  • True hermaphroditism - condition where both male and female internal sex organs are present

Summary

Causes of hirsutism are diverse. But the basic defect in all the causes of hirsutism is increased action of male sex hormones - the androgens.

Unknown causes of hirsutism:

In the unknown or the idiopathic category, the causes of hirsutism are not known. The affected person is healthy till puberty and thereafter develops hirsutism. In this category the hirsutism is usually familial. There will be an associated obesity and insulin resistance. Some of the patients in this category have normal blood androgen levels. In these patients the cause of hirsutism is increased sensitivity of the body to normal androgens.


This page was last updated on June 20, 2006

 


 


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