Causes of Hair Growth
Non-Hormonal Causes for Extra Hair Growth
Most women seeking help with removing unwanted hair will likely have Polycystic Ovary Syndrome (PCOS), a common endocrine condition that causes higher testosterone levels in women. However, there are non-hormonal causes of extra hair growth in both men and women.
Hormonal or testosterone driven extra hair growth is called hirsutism. on-hormonal extra hair growth is called hypertrichosis. Hirsutism appears in a pattern on specific areas of the body that are, by definition, driven by testosterone. These areas include the upper lip, sideburns, chin, neck, chest, lower abdomen, lower back, buttocks and inner thighs. Testosterone causes these hairs to become thicker, darker and coarser. Conversely, hypertrichosis is usually generalized extra hair growth and can involve lanugo (downy hair on a newborn), vellus (fine hair / peach fuzz) or terminal hair (thick, coarse and usually dark hair).
There are both congenital and acquired causes of hypertrichosis. Congenital causes are generally quite rare with the exception of one condition called Prepubertal Hypertrichosis. This condition presents in healthy infants and continues through childhood and adulthood. The hair growth is often present on the temples, spreading across the forehead involving the eyebrow and there is often marked hair growth on the upper back and arms. This hair growth involves the terminal hairs but is not driven by higher testosterone levels and is not associated with PCOS.
Acquired causes of hypertrichosis include mediations and some disorders. The medications that most commonly cause hypertrichosis are phenytoin, cyclosporine and minoxidil. Phenytoin is a medication that is used to control seizures in people with seizure disorder or in people that have had a brain injury to prevent a new seizure. Cyclosporine is a medicine that lowers a person’s immune response and it is sometimes given to people who have had organ transplants, rheumatoid arthritis or psoriasis. Minoxidil is a medication that can be used for severe hypertension when it is taken by mouth. When it is applied topically, as Rogaine, it is used to prevent scalp hair loss in both men and women. At the higher prescription dose of topical minoxidil, extra facial hair growth has been reported.
There are disorders that can also cause acquired hypertrichosis. Malnutrition caused by a variety of situations including anorexia and celiac disease can cause extra hair growth and is primarily found on the trunk of the body and limbs. This is thought to result from the carbohydrate restriction that occurs in these types of disorders. Other diseases that may result in generalized hair growth are liver injury, brain injury, childhood onset of hypothyroidism and HIV/AIDS.