Ask Dr. H: Hair loss among combat soldiers

Question:

Is the early onset of male pattern baldness connected to the stress of military service? I ask this because many young men returning from active duty in Iraq and Afghanistan appear to be balding earlier than males of roughly the same age that are in the general civilian population.

Answer: Stress from combat can cause temporary hair loss - a condition known as telogen effluvium. But it doesn't cause male pattern baldness, also known as androgenic alopecia. Throughout history, soldiers have been observed to have hair loss shortly after joining the military. Some have questioned whether their tight-fitting hats and helmets are to blame.

It turns that it's just a coincidence: The average age that men begin to notice their hair thinning or receding from male pattern baldness coincides with the ages at which many men are in military service, wearing helmets and experiencing hair loss. Genetic factors, rather than stress or tight hats, are to blame for male pattern hair loss.

The abrupt but temporary hair loss seen following the stress of war is caused by large numbers of hair follicles entering in synchrony a stage of rest in the normal hair cycle. The stressful event typically precedes the observation of hair loss in clumps by about three months. After the three-month rest period, the hair follicles enter a new stage of hair growth that causes the old hairs to fall out in clumps. This form of hair loss is temporary, unlike male pattern hair loss, which is permanent.

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Q:

I am pregnant with my second child. Because my blood type is O-negative, I had the Rhogam shot with my recent amniocentesis. I know that the shot was necessary to protect my baby, but what about the thimerosal preservative in Rhogam and its risk of mercury harm to my baby?

A: Let me first put your fears to rest. Since April 2001, Rhogam is no longer using the mercury-containing thimerosal preservative in its product. Also, the FDA has not determined conclusively that pre-2001 Rhogam preparations preserved with thimerosal caused fetal harm.

Before the introduction of Rhogam in 1968, Rh blood type incompatibility between a pregnant mother and her developing baby claimed 10,000 babies in the United States each year. Remember that in pregnancy there are two separate blood circulations: mother and baby. If the mother's blood type is Rh negative (e.g., A-negative; O-negative; B-negative; AB-negative), and the baby's blood type is Rh positive, the mother's blood will produce antibodies against the baby's Rh positive blood capable of causing life-threatening destruction of the baby's red blood cells. The Rhogam shot blocks the antibodies produced from an Rh negative mother so as not to cause any harm to a developing baby. These antibodies are not usually formed in high numbers until after the first pregnancy. That means that Rhogam isn't usually needed in the first pregnancy. You definitely needed the Rhogam as a precautionary measure - even if it turns out that your second baby is Rh negative like you. For more information on Rhogam, check out the Web site: www.rhogam.com.