What Are the Causes of Excessive Hair Growth in Girls?

Excessive hair growth, called hirsutism, can cause enormous embarrassment to young girls. Hirsutism is most often caused by an excess of male hormones, called androgens. Hair often grows in more typical male hair growth patterns in hirsutism, with facial hair and body hair in atypical female patterns. Other signs of excess male hormones, called virilization, may also occur, such as voice deepening, acne or an increase in genital size. A number of diseases can cause hirsutism 6.

Adrenocortical Carcinoma

Adrenocortical carcinoma occurs rarely in children, causing less than 0.2 percent of all childhood cancers, St. Jude Children’s Research Hospital reports. Adrenocortical carcinoma can cause excess androgen production leading to hirsutism and other signs of virilization in girls. Treatment of adrenal gland carcinomas, which sometimes run in families, is surgical removal of the adrenal gland.

Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia affects the adrenal glands. It is a genetic abnormality that causes decreased production on enzymes necessary for cortisol production. Congenital adrenal hyperplasia leads to overproduction of male sex hormones, which can cause ambiguous genitalia in girls from enlargement of the clitoris, early puberty, acne and hirsutism. Medications to raise low levels of hormones such as cortisol can help reduce elevated androgen levels.


Corticosteroids, medications that suppress the immune system, such as for cancer, autoimmune disease or severe asthma, can cause Cushing syndrome if taken long-term. Cushing’s syndrome occurs after prolonged exposure to natural or man-made forms of cortisol. Weight gain, moon face, excess fat on the back of the neck, fatigue, high blood pressure and growth retardation can occur along with hirsutism in girls with Cushing’s syndrome from taking corticosteroids.

Polycystic Ovary Syndrome

Polycystic ovary syndrome, or PCOS, the most common cause of high androgen levels, according to TeenHealth from Nemours, occurs when the ovaries produce a larger than normal amount of male hormones. Girls with PCOS don’t normally have symptoms until adolescence, although early puberty can indicate potential PCOS. Irregular menstrual periods, severe acne, extra weight, especially around the waist and dark, thick skin around the neck and under the arms can accompany hirsutism in PCOS sufferers. Obesity, heart disease, high blood pressure and abnormal uterine bleeding and cancer occur more frequently in women with PCOS, which can be treated with medications such as birth control pills and medications to reduce androgen levels.