I read that you should not vaccinate for MMR if your child has an egg allergy. I found out that my 17-month baby girl gets a rash from egg whites. What kind of problems can occur when she receives the MMR vaccine? Should she not have it?

The current measles-mumps-rubella vaccine (MMR) does not contain a significant amount of egg proteins (but two other vaccines do). As recently as 1994, the AAP recommended skin testing of all children with severe egg allergies before they received the MMR. This is no longer necessary. Even those with dramatic egg allergies are extremely unlikely to have an anaphylactic reaction to the MMR. The benefits of the vaccine far outweigh the risks.

Most people don't know that the influenza vaccine ("flu shot") contains egg protein. People who react to eggs, chicken, or chicken feathers with systemic symptoms (a drop in blood pressure, significant wheezing, difficulty breathing, or generalized hives) generally should not get the flu vaccine. Localized or less severe reactions (such as a mild rash) to feathers or eggs are not a reason to forgo the vaccine. Allergy to duck meat or duck feathers is not a reason to hold back on any vaccine.

The yellow fever vaccine also contains egg protein. Yellow fever is still a major problem for people living in or traveling to tropical South America or Africa. This vaccine can be very important. Thus, rather than skipping it, most candidates for the vaccine who have a suspected allergy should get a series of two skin tests with the vaccine. If both tests are fine, proceed with the vaccine. If either test shows a reaction, a process of desensitization is begun. Similar to allergy shots, a series of tiny doses of vaccine are given to reduce the risk of reaction.

Although egg protein in the MMR is no longer a big problem, if your child has severe allergies with systemic symptoms, whatever the cause, it pays to become familiar with the hidden ingredients found in products of all kinds.