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Pediatrics/Mycoplasma pneumoniae


My nephew of 3 years old at first, and later my mother, they have been infected by Mycoplasma pneumoniae. Doctors says that after the treatment, infection has disappeared, that only IgG remains positive. But i don´t know why every time that my nephew get sick my mother too. The worst part goes for the kid because often his lungs are affected. The main question is żIf a reinfection or relapse occurs, IgM will be positive or negative?

Hi, Jose,

With recurrent coughing, one has to think about other conditions like asthma.  It would be unusual to have a relapse of mycoplasma.  IgM can be used to follow this.  If this is a new infection or a relapse, the IgM should be positive.  What I don't know is how long the IgM remains positive after an initial infection.  My guess would be for 2-4 weeks, based on IgM response in other illnesses.  In my six person peds practice in Michgan, we virtually never order mycoplasma gammaglobulins.

Good luck, Dr Olson


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David Olson, MD


I would be happy to attempt to answer any questions about general pediatric topics, either medical issues or behavioral issues. This would include all the various questions one receives in a busy pediatric practice. I`m a board certified pediatrician in northern Michigan and have been in practice for over 15 years. I enjoy the teaching role I have in our practice and would enjoy the opportunity to help others with their pediatric problems.

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