Thank you for your question.
I am Dr. Su S. and I will try my best to help you.
As he is getting the infection repeatedly, I would advise to get her examined by an ENT specialist, if you have not taken already.
A blood count, swab, scope would be helpful.
Swab can be taken for culture & sensitivity.
If the ENT specialist thinks necessary, he can refer to an infectious disease specialist.
I hope this information will be helpful.
If you have any query, please feel free to ask.
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Wish her healthy life.