Virilization, as a disease, occurs when androgen-induced male characters appear at the wrong time of development, or in the wrong sex, i.e. girls and women. In most cases, this is due to overproduction of androgens because of adrenal hyperplasia. But virilization may indicate other, serious problems, i.e. tumors in the ovaries or adrenal glands.
Hirsutism, (unusually thick, male-pattern growth of hair), accompanied by no other symptoms, or much milder ones than those occurring in virilization is often associated with the polycystic ovarian syndrome (PCOS).
Most cases of virilization  are due to congenital adrenal hyperplasia (CAH). The presentation of adrenal virilism depends on the sex of the afflicted individual and the stage of life when the disease is manifested. A baby girl born with the disease (the more severe, classical form ) displays various degrees of masculinization in the external genitalia (pseudohermaphroditism), sometimes to the extent that her sex is erroneously assigned as male . In the less severe, non-classical form the symptoms may appear some years after birth. Affected girls born with normal external genitalia will show some characteristics of virilization, whereas boys will show early puberty.
The presence of excessive androgenic hormones – such as testosterone - is characteristic of this syndrome, which is as expected for the virilizing effects seen . These hormones speed up growth; stimulate the maturation of bone structures; enlarge the clitoris in girls and the penis in boys, and cause hirsutism and acne. Further symptoms include deeper voice, balding of the head and reddening of the skin, developing stronger muscles, the cessation of periods, and increased sexual drive in women.
Some newborn babies present with a version of the disease in which there is a deficiency in maintaining normal salt and water concentrations  . In these patients mineralocorticoid and salt supplementation are necessary; in the past many of these infants have died  .
A diagnosis of virilization needs to differentiate between adrenal and ovarian origins, as well as between hyperplastic states and tumors as sources of the disease. It should be remembered that mild symptoms, or just hirsutism coupled with scanty periods and elevated testosterone levels, may indicate the most frequent condition of androgen excess in women: the polycystic ovary syndrome. This is a complex disease, with a somewhat problematic diagnosis  . The examination of adult women should include ultrasound tests, determination of hormone levels, and biopsy for evaluating histopathological results. The latter is especially important if the symptoms are atypical or develop unusually fast, indicating the presence of ovarian or adrenal tumors   . Exogenously added androgens also have to be considered in the diagnosis.
Finding increased concentrations of adrenal androgens   in the urine verifies adrenal virilism. Results at the high end of the urinary 17-ketosteroid assay can indicate adrenal disease, of which the most common is due to a deficiency of the 21-hydroxylase enzyme  . Conversely, when urinary ketosteroid levels are in the low to normal range, it suggests an ovarian source for the disease . Urinary 17-ketosteroid elevation can also be used to differentiate men with the adrenogenital syndrome from patients with other forms of sexual precocity.
The following androgens are elevated in the urine in adrenal hyperplasia: dehydroepiandrosterone (DHEA), its sulfate (DHEAS), and frequently pregnanetriol. DHEA and DHEAS, together with 17-hydroxyprogesterone, testosterone, and androstenedione may also be in the high range in the plasma.
The suppression of symptoms with exogenous steroid can be used to make the distinction between hyperplasia and autonomous adrenal tumor. Thus, tumors as the source of virilization can be ruled out if dexamethasone suppresses the androgen levels . If no suppression is observed, the adrenal glands and ovaries should be examined by computerized tomography (CT), magnetic resonance imaging (MRI) or ultrasonography, to find a possible tumor. Stimulation by the administration of synthetic adrenocorticotropic hormone (cosyntropin) is expected to raise the 17-hydroxyprogesterone level if adrenal hyperplasia is the source of virilism .