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Month: October 2011

My aging immune system…and flu shots

My aging immune system…and flu shots

 Dear Dr. K: I read that since I’m 68 years old I won’t get as good immunity from the flu shot as a 30-year-old. Am I wasting time by getting vaccinated?

The complete and total answer to your question is “No.” However, let me elaborate.

The issue at hand is immunosenescence, or aging of the immune system. Just like other parts of our body, our immune systems age. It is for that reason that persons over age 50 are more likely to get shingles and to die from influenza. We (I can say that since I’m over 50) also are more likely to get bacterial pneumonia, urinary tract infections, meningitis, gastroenteritis and tuberculosis.

Because of these risks, it makes it all the more important to take preventive steps to bolster our immunity.

People over 65 get only 56 percent of the protective effect of flu vaccine and only 65 percent of the protective effect of the pneumonia vaccine, as compared to young people. Still, that 56 and 65 percent improvement is better than 0 percent.

There has been intense research on the aging immune system, especially with the wave of baby boomers enlarging the elderly population. One unexpected finding was that in addition to increased risk of infection in people over 50, there is a specific infection that by itself can actually speed the senescence of the immune system. The culprit is a virus called CMV – Cytomegalovirus.

As it turns out, this dastardly virus reduces the helper T-cell lymphocytes which are so important in building good immune function. CMV is in the family of herpes viruses and once you’re infected, it stays with you life long.

Since CMV is fairly common, there is intense research into finding a way to prevent its immunologic mischief.

Big word, important concept – Dermatographism

Big word, important concept – Dermatographism

Dermatographism is a term that comes from Greek and Latin words dermos (skin) and graphia (to write). It literally means to write in the skin and thus, describes an exaggerated cutaneous response to physical stimuli in the form of hives.

The physiologic mechanism is histamine degranula-tion from mast cells in the skin by mechano-immuno-logic triggers. Thus, systems of burning, itching, redness and welting occur from pressure such as tight clothing, belts and bra straps.

Stroking the skin or scratching can also lead to symptoms, as can continuous pressure such as sitting (on your buttocks) or standing (on your feet).

There are some subtypes of dermatographism such as the cholinergic form. This form is worse when the body is heated as from exercise, a hot shower or a fever. Follicular dermatographism tends to center around hair follicles and manifests as several papules rather than larger welts.

White dermatographism is, as the name implies, blanching of the itchy skin rather than redness, and is due to vasoconstriction (blood vessel narrowing). Cold-dependent dermatographism requires cold exposure.

Dermatographism can be primary (inherited) or secondary. Secondary can be systemic disease-induced such as hyperthyroidism, diabetes and mastocytosis; drug-induced as in allergic reactions (especially to amoxicillin, cephalosporins, atorvastatin and famotidine); from infectious triggers (this is especially common in children with strep infections and viruses), and from psychological factors such as stress and anxiety.

The mainstay of treatment is antihistamine drugs. Usually a combination of a histamine one (H1) receptor blocker and a histamine 2 (H2) receptor blocker is required. A combo that often works well is Zyrtec (H1) and Zantac (H2).

In more severe cases a third drug can be added – a leukotriene modifier (Singulair or Accolate). Also, phototherapy using narrow-band UVB has been shown to be helpful.