There are many different causes for hair loss. Thankfully, many of these causes for hair loss can be halted and prevented. A certain amount of hair loss is normal: We lose up to 50-100 hairs each day. Hair follicles go through a growth phase known as anagen. The length of the anagen phase for hair follicles around the body varies, which is why your eyebrows don’t grow as long as the hairs on your head (thankfully). Once the growth phase ceases, hair growth temporarily stops, and the hair is shed. The process starts with a new hair in the next anagen growth phase. So, in most cases, loss of hairs is normal. It is when we start to lose hair faster than we can grow it that hair noticeable loss and thinning occurs.
Causes of Hair Loss
Male & Female Pattern Baldness
The most common cause of hair loss is an inherited condition known as androgenetic alopecia, also known as male-pattern or female-pattern baldness. This affects nearly 80 million men and women in the United States alone. Male and female-pattern hair loss is a genetic and hormonal disorder. The hair follicles have a higher sensitivity to the sex hormones testosterone and dihydrotestosterone (DHT). This causes the hairs to shrink and eventually stop growing altogether. It starts as a thinning of the hair on the forehead for men and on the top of the scalp for women. Then the thinning and hair loss can progressively spread.
Thankfully, if addressed early, this kind of hair loss of treatable. Treatment options are most effective during this early period before hair follicles become irreversibly changed. Medications like finasteride (Propecia®) helps reduce the effects of testosterone hormones on the hair follicles. Minoxidil applied to the scalp promotes hair follicle activation. PRP injections directs the body’s own growth factors to the hair follicles to activate dormant hair follicles and increase blood supply. Ultimately, one can undergo hair transplant surgery, where unaffected hairs are moved to balding areas.
Telogen effluvium is a condition in which the growth phase of the hair follicle stops prematurely. This can be caused by systemic trauma or stress to the body, including illnesses, surgery, major life stressors, sudden weight loss (crash dieting), medications, and more. Telogen effluvium hair loss can be alarming because large amounts of hairs are falling off the scalp in a short period of time. Thankfully, the hair follicles involved are not damaged but are merely “sleeping”. Once the body is given time to recover, the hair follicles turn on and begin growing hair again.
Alopecia areata is an autoimmune disorder. The immune system attacks the hair follicle, releasing inflammatory factors that shut the hair growth off. It appears as sudden round bald spots on the scalp. Alopecia areata can sometimes be triggered by viral infections, trauma, hormonal change, or emotional and physical stressors. The hair follicle is not permanently damaged by the immune system however, and as soon as the inflammation improves, hair will begin to grow again. This is achieved commonly with injections of low potency steroids.
Other Causes for Hair Loss
Other factors that can contribute to hair loss are harsh hair care practices. Perms and heating of the hair can damage the hair follicles. This can cause permanent scarring, disrupting hair growth. Tying the hair tightly can also put extra strain on the hair follicles on the front of the scalp, causing irreversible damage. Other causes of hair loss include metabolic disorders, nutrition deficiencies, thyroid issues, new medications, pregnancy, and more. Those experiencing hair loss should consult a board-certified physician for an evaluation of possible causes and treatments.