Hair loss is a sensitive issue for both men and women. Men, however, tend to lose more hair earlier and faster than women, largely because of hormones and heredity. In fact, the decade of a man’s age corresponds to the percentage of men who are losing their hair. In other words, 10 to 20 percent of men in their teens and twenties begin to experience hair loss. By age 50, about half of men are balding, and nearly two-thirds have moderate to extensive hair loss by age 60.

The most common type of hair loss in men is male pattern baldness, or androgenetic alopecia. This familiar U-shaped pattern of hair around the sides and back of the scalp is what’s left when the hairline recedes and hair on the crown of the head thins.

The hormone to blame for androgenetic alopecia is called dihydrotestosterone, or DHT. When levels of this sex hormone are elevated, it causes hair follicles to shrink and stop producing hair. Many people mistakenly believe that male pattern baldness is passed down from your mother’s father but, in fact, it can be inherited from relatives on either side of your family – or both.

So what if your DHT levels aren’t elevated, and there’s no male pattern baldness in your family tree – but you’re still losing your hair? The first thing to rule out is underlying disease, such as diabetes or a thyroid condition, that may have hair loss as a symptom – which underscores why it’s important to have a comprehensive exam with a qualified physician. If things check out in that regard, these are some other fairly common culprits in hair loss:

Telogen effluvium is probably the second most common type of hair loss I see in my practice. It’s characterized by an often acute onset of significant hair loss – handfuls at a time. What’s usually to blame is a traumatic event or experience – an illness, accident or emotional shock to your system. Certain medications can also contribute to this condition, including beta blockers (for high blood pressure or heart disease), anticoagulants, antidepressants, NSAIDs or retinoids. A poor diet that results in low protein intake or iron deficiency (anemia) can also be a factor.

To understand how telogen effluvium occurs, it’s important to understand the human hair growth cycle. Each hair on our head grows for two to six years at a rate of about a half-inch per month. At any given time, about 85 percent of our hair is in this growth phase (also called the anogen phase). The hair then rests in what’s called its telogen phase, and falls out. Soon afterward, a new hair starts to grow in its place.

With telogen effluvium, however, a traumatic occurrence causes hair follicles to prematurely enter the telogen (resting) phase, setting off a sudden and major hair loss. On a positive note, though, this condition is almost always temporary and gets better on its own.

An autoimmune skin disease called alopecia areata is a more challenging culprit in hair loss. It usually starts with one or more small, round and smooth patches on the scalp and can progress to other parts of the body. Because everyone is unique, the disease course is different for each person.

A fungal infection called tinea capitis can also cause hair loss on the scalp, eyebrows and eyelashes, causing bare patches in these areas.

And a condition called trichotillomania – hair loss that’s caused by compulsive twisting or pulling of the hair until it breaks off – affects as many as 10 million Americans. About 10 to 20 percent of reported adult cases are men.

The bottom line is this: it’s completely normal to lose about 100 hairs a day as part of our hair’s natural growth cycle. But if you’re bothered by more extensive hair loss, it’s important to see a qualified physician for an accurate diagnosis, and a candid discussion of the medical and surgical treatment options available to you. For male pattern baldness, in particular, having a permanently full and healthy head of hair again can be a reality with today’s advances in hair transplantation and restoration.