What Causes Hair Loss?

What causes hair loss? Now that is a complicated question without a simple or often straightforward answer. There are a number of different things that may lead to hair loss. Issues like hormone imbalances, medications, trauma, autoimmune conditions, infections, and dermatological (skin) conditions, amongst other things, can all cause hair loss. Because of the broad array of different conditions that may cause hair loss, it is important for any patient experiencing thinning or the appearance of “patches” in the scalp to see a medical doctor who specializes in hair loss.

While there are many conditions which may lead to hair loss, there is one infamous culprit: genetics.

The same “family genes” which are responsible for things like eye color and height are also the cause of the two most common types of hair loss: genetic male pattern hair loss (MPHL) – also known as “male pattern baldness” and genetic female pattern hair loss (FPHL) — both scientifically known as androgenic alopecia or androgenetic alopecia; “andro” meaning hormone, “geneic or genetic” meaning genes, and “alopecia” meaning hair loss.

Female pattern hair loss is a little more complicated compared to its male counterpart. And while experts agree that genetics are the main underlying cause, a complex and somewhat poorly understood pathway involving multiple hormones is directly responsible for the thinning hair. Female pattern hair loss typically begins in the middle of the scalp and progresses in an outward spreading pattern. Women typically first describe the thinning as a “widening” of their part, which then turns into a generalized thinning throughout the top of the scalp (and often involving the entire scalp). It’s usually first noticed between the ages of 40s-60s, and may accompany life changes like menopause or pregnancy. Females who believe they are suffering from FPHL should a doctor familiar with hair loss (an endocrinologist or hormone specialist if possible) to undergo lab work and discuss possible causes and treatment.

MPHL is more common and more straightforward. Estimates state that approximately 50% of men experience genetic hair loss at some point in their life; this number increases to nearly 80% as men reach their late 70s or early 80s. Like FPHL, a series of genes are responsible for the underlying hair loss. The direct cause, however, is a single hormone: dihydrotestosterone or DHT, an offshoot of testosterone – the most common “male” hormone in our bodies. DHT is a naturally occurring and important hormone, and all men have it in their systems. Only some men, however, have hair follicles which are “sensitive” to DHT. Those with sensitive follicles experience varying degrees of male pattern hair loss; those without sensitive follicles will not. The hair loss can occur at almost any age, but begins most frequently in the 20s or 30s. It progresses in classic “patterns” – hence the name – which begin with recession in the frontal hairline area (particularly in the “corners” above the eyes) and the “crown” area in the back (sometimes lovingly referred to as the “bald spot”). Those with advanced MPHL eventually progress to complete baldness on the top of the scalp with only a fringe of hair remaining on the sides and back of the scalp (follicles which are genetically resistant to DHT). Because MPHL is more straightforward and better understood, diagnosis and treatment is simpler as well. Men who believe they have MPHL should see a hair loss specialist and determine whether they are a candidate for FDA approved preventive medications (Propecia (finasteride) and Rogaine (minoxidil)) or hair transplant surgery.