

— Andrea, California




Q2. How can I find an allergy medication that doesn't make me sleepy? Why do they all seem to have this side effect?

Older antihistamines are sedating because the medication penetrates the blood-brain barrier, which means that the medication not only works in treating allergy but also affects the brain. The result is a feeling of lethargy. In fact, some older antihistamines are prescribed specifically because they help with sleep and relaxation. But clearly, this can be an unwanted and serious side effect for someone who needs to drive or operate heavy machinery.

Newer, once-a-day antihistamines have no effect on the brain and just function in reducing the symptoms of allergy – that is, they block the chemicals called histamines that cause inflammation, mucous, itching and hives. They can still cause drowsiness in about 10 percent of people who take them, however, and this may be the case for you. You should talk to your doctor about other approaches, which might depend on your type of allergies, their severity and your symptoms.

Q3. About a month ago, I had an allergic reaction caused by penicillin. Ever since, I have had a phobia that other medications will cause that kind of reaction in me. Could this happen? Is there any chance that I have become allergic to other drugs too?

— Vivi, Greece

Don't panic. Penicillin causes more allergic reactions than any other medication, so your experience is not unusual. Many people develop rashes while taking penicillin, and the majority of these rashes represent non-life-threatening allergies. People should still avoid the causative drug, but the risk of ever having a really dangerous reaction is relatively low.

There are two types of drug reactions indicative of a potentially dangerous sensitivity that could be even worse if the medicine is taken again:

  • IgE reactions, which involve hives (raised, red, intensely itchy spots that last a few hours each and come out in crops over days to a week, even after stopping the drug), swelling (usually of the face, mouth, throat, or extremities), or difficulty breathing/asthma-like symptoms. If a person had a reaction to penicillin with some or all of these features, then skin testing is helpful for determining if they are really at risk for future similar reactions, including anaphylaxis (a sudden, severe, potentially fatal, systemic allergic reaction). See my recent column on Seafood Allergies for more on IgE reactions.
  • Steven-Johnson/toxic epidermal necrolysis reactions, which cause high fever and blistering of the skin and linings of the eyelids, mouth, and intestinal and genital tracts, with extensive peeling afterward. These reactions are very rare. Skin testing is not useful for confirming this kind of allergy.

If your reaction was like either of the two above, you should talk to your doctor carefully about it and make sure you have taken the proper precautions. Referral to an allergy specialist might be in order to evaluate the reaction further. However, most people who have less dangerous reactions simply avoid the medication, and they tolerate other medications without problems. Also, it is possible to rid yourself of some medication allergies over time — especially if you successfully avoid any additional exposure for a period of years. The good news is many people have this allergy, and it is the only medication to which they ever become allergic. However, if a person has had allergic reactions to several medications, it becomes clear at that point that they are at higher risk to become allergic to still more. However, there is no way to predict early on what will happen in any given individual.

As a corollary, medication allergies are more common in people who have been exposed to a lot of medications, so your phobia may offer you some advantages. Always ask your doctor if an antibiotic or medication is really necessary. Many practitioners assume that patients want antibiotics and this influences their decision to prescribe them, when it may not be completely clear that one is needed. If you mention that you would rather avoid antibiotics when possible, you'll probably find your doctor to be pleasantly surprised; he or she may suggest that you wait a week or so to see if the problem clears on its own. This advice applies best to colds, bronchitis, sinus infections, urinary tract infections, and minor skin infections. Although there are certain serious infections, most of which cause several days of high fever, for which treatment should not be delayed, and your doctor would inform you.

Q4. I have really bad hay fever in the spring and the fall, but I'm fine the rest of the year. How far in advance should I start taking my allergy medications?

You should start taking your medications at the same time the plants that trigger your allergies start to pollinate. The spring pollens are trees and grass. Trees start to pollinate at the beginning of March, and grass starts to pollinate at the beginning of May. For spring allergies, start medications in early March.

Fall pollens include ragweed and other weeds, which start to pollinate around the middle of August. So that's when a fall allergic person should start treatment.

Learn more in the Everyday Health Allergy Center.