Adrenal Causes Of Hirsutism

Congenital adrenal hyperplasia (CAH) is the result of a congenital error of steroid synthesis in which a partial block of cortisol synthesis results in increased corticotrophin secretion and hence increased androgen (male hormone) secretion. The degree of hirsutism, however, depends very much on the skin sensitivity to androgens.

The commonest variety - 21-hydroxylase deficiency - is inherited as an autosomal recessive trait. It is usually diagnosed in female infants during the neonatal period because of ambiguous genitalia. A partial deficiency of this enzyme may, however, remain unrecognised until puberty or later, when hirustism, amenorrhoea and virilisation may develop. This is so called acquired, late onset, adult onset, attenuated or incomplete CAH.

The second commonest variety is 11-beta-hydroxylase deficiency, which is associated with hirsutism or virilism and hypertension as a result of excessive production of both androgens and mineralocorticoids.

A rare cause of CAH resulting in androgen excess is 3-beta-hydroxysteroid dehydrogenase deficiency. Since this enzyme is normally found in ovaries the condition is also accompanied by ovarian hyperandrogenism.

Adrenal tumours resulting in androgenisation without symptoms and signs of glucocortiocoid excess are rare. Virilisation is as a rule feature of adrenal carcinoma.