Hair Composition and Growth
To start, the scalp has about 110,000 hair follicles, or the originating place from which hair sprouts. Hair grows about a half-inch a month, on average, and about 90 percent of the time, hair is growing. The other 10 percent is when the hair is going into, or is in, a resting phase.
There are three phases of hair growth. The “anagen” phase is when the hair grows in length. This period lasts between two to six years. The next phase, the “catagen” phase, is transitional. This period lasts about two to three weeks and prepares the hair for the next phase. The “telogen” phase is when the hair rests, older hairs are shed and replaced by new hairs.
Hair is composed of keratin, a tough protein. Keratin is produced in the hair bulb, at the bottom of the hair shaft, anchored under the skin by the follicle. In the hair bulb, cells divide and grow to build the hair shaft, the part that protrudes beyond the skin. Blood vessels in the hair bulb feed nutrients and hormones to the hair that modify growth and structure at different times of life. Pigment cells produce melanin for hair color, but with age, these cells die. Subsequently, there is a decrease in pigment and an increase in gray or white hair.
Hair Loss
In the U.S., 35 million men and 21 million women struggled with hair loss in 2014. Excessive hair loss is estimated to be in the range of 100 or more scalp hairs a day, although losing one’s body hair is also a possibility. Hair loss may be an inevitable part of life. Thinning hair is probably a combination of genes and aging. But certain medications, ones you may presently consume, can cause predominately two different types of hair loss.
Telogen effluvium, the most common form of medicine-induced hair loss typically appears two to four months after the start of the offending medication. The drug causes the hair to go into the telogenic phase too quickly, which then causes the hair to fall out prematurely. In most cases, the hair follicles are the affected part of the hair to be affected by these meds. Usually there is shedding of about 150 or more scalp hairs a day.
Anagen effluvium, is less common and affects the hair in the growth phase. Matrix cells, which construct new hairs, are prevented from normal functioning. The effects of the medications on hair development happen relatively quickly, usually within a few days or weeks. This type of hair loss is most commonly seen in chemotherapy patients. The side effects are often severe with hair loss on the scalp, eyebrows, eyelashes and other body hair.
Commonly Prescribed Medications That Could Cause Hair Loss
There are a surprising number of commonly prescribed medications that could cause hair loss. Please remember that all medications do not affect different people the same way so hair loss could be non-existent, mild, moderate or severe. But if you are at all concerned about your hair, consult your physician. There may be alternatives that don’t have the same kind of bothersome side effects.
1. Oral contraceptives – These meds can cause hair loss to many women who use the various birth control devices that contain hormones -- such as the pill, Depo-Provera, or the vaginal “O” ring. Due to changing levels of circulating hormones, the degree of hair loss will vary over time.
2. Anticoagulants or blood thinners – The administration of these drugs can cause a telogen effluvium response with the whole scalp involved. Hair loss typically starts about 12 weeks after first starting on blood thinners.
3. Beta blockers – This medication reduces the workload on the heart, slowing it down a bit. In this way, blood pressure is also lowered. Unfortunately, these drugs can cause a telogenic effect.
4. Male and female hormones – High levels of testosterone or use of anabolic steroids may exacerbate male pattern baldness in men and a general thinning of hair in women. Estrogen and progesterone can also be disruptive to hair growth.
5. Antidepressants – High levels of stress can cause temporary bald spots on the scalp. Depression and anxiety themselves can cause hair loss and so can the medications used to remedy these illnesses due to a telogenic effect.
Because this is a subjective list, and there is a plethora of medications that have an effect on hair growth, here is a fast listing of a fair amount of drugs that could thin your hair out.
Acne meds, (because of high levels of Vitamin A or retinoids); antibiotic and antifungal drugs; cholesterol-lowering drugs; meds that suppress the immune system; arthritis medicines; anticonvulsants; ACE inhibitors, diuretics and other blood pressure drugs; NSAIDS; Parkinson’s disease medication; thyroid meds, and some weight-loss drugs.
Some medications will cause male- or female-pattern baldness, which could lead to permanent hair loss. But before you stop taking the offending drug, talk to your doctor. Suddenly stopping a needed medication can be dangerous to your health and lead to unpleasant withdrawal symptoms.
Growing your hair back?
If, with your doctor’s blessing, you stop taking the drug that is causing hair loss, give yourself time to get the drug out of your system. You should notice a change in hair growth within a couple of months. If hair doesn’t return, there are now over-the-counter hair-growth medications you can use. But again, talk to your doctor to make sure these products are appropriate for you and won’t interfere with any other drugs you may take. Unfortunately, some hair loss may be permanent.
Remember, hair loss without an apparent reason is a sign something is not right in your body. If you are on medications and experience hair loss, do your research into these drugs, ask your doctor for side effects but also read the information that accompanies your meds. And if you have access to the Internet, dig around and find out more about the drugs you take. As always, information is power, especially when it comes to prescription medications.