Dear Dr. Roach: Can you tell me if there is any hope of a cure for tree-nut allergy, particularly for a child?


Dear X.M.: Tree-nut allergies, like all allergies, vary in severity from mild to life-threatening. Allergies to tree nuts (these include walnuts, cashews, almonds and others) are common, are more likely to be severe, and tend to persist throughout lifetime. People with one tree-nut allergy may have others, and about 30 percent to 40 percent also may be allergic to peanuts (despite their being legumes, they share enough characteristics for co-allergic reactions). Peanut and tree-nut allergies appear to be increasing in prevalence over time.

The mainstay of treatment is avoiding the allergen, which requires constant vigilance, careful reading of nutritional labels and a plan for treatment in case of ingestion, such as an epinephrine auto-injector.

Only about 15 percent to 20 percent of younger children will develop tolerance to (“outgrow”) their allergy, and allergy usually is lifelong if it develops later in life. Your allergist can do skin testing to see if the allergy is resolving.

Dear Dr. Roach: I just read your Q and A “Blood donation can affect athletic output.” Your answer is correct, but you missed a key opportunity to educate your readers.

There is an alternative for him: Instead of donating whole blood, he can ask his local Red Cross about donating via apheresis (as I do). The apheresis process requires more time (up to two hours) and attaches the donor to a centrifuge machine, which separates the donor’s whole blood into red cells, plasma and platelets. Each of those blood products is then either bagged for collection (if needed at that time by the Red Cross) or returned to the donor’s bloodstream (if not). The donor always retains the right to specify which blood products may or may not be drawn, so your reader can always say, “I prefer not to donate reds today, but feel free to draw plasma and platelets,” if he knows he has a challenging athletic event coming up.

In my case, I usually donate platelets and plasma about every six weeks via apheresis, but normally not red cells. One advantage of not donating reds is that a donor can return to donate plasma and platelets more frequently. During my most recent donation, my nurse mentioned that there was a serious shortage of platelets but that the supply of red blood cells was fine, so she had been instructed to NOT draw reds from any donor if that donor was able to schedule another donation of platelets in the next few weeks.


Dear M.M.: Thank you for the important information.

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