Q. High fever and swollen lymph node. Is it a bacterial or viral infection?

Answered by
Dr. Faisal Abdul Karim Malim
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on Jan 30, 2018 and last reviewed on: Oct 26, 2022

Hello doctor,

My son has been sick with a high fever (between 101.7 to 103 degrees) and swollen lymph node on one side of his jaw right beneath his left ear, complained of pain in the neck, and pain inside his mouth. I took him to his pediatrician the following day and was prescribed Clindamycin 150 mg three times a day for 10 days. His doctor made a big mistake by not doing any throat culture for a definite diagnosis of what she suspects as a strep/staph bacteria on his lymph node. I did not doubt the doctor then and gave him the antibiotics as prescribed.

I took him back to the office on Tuesday to be seen by another doctor in the facility to do a rapid test for strep which of course came out negative since he was already taking the antibiotics. He was not getting better but worse the following days with fever not reducing, worse pain inside his mouth, not eating, skin over the lymph node turning red, and also generally feeling ill.

I thought the antibiotics were not working after three days of taking Clindamycin. So, took him to the ER. ER doctor gave him one dose of Clindamycin through the IV and although his fever was still present, the redness on his lymph node diminished a bit. He had an ultrasound and they said it was not an abscess. They drew some blood to also check for mono which we do not have the result in yet. They sent us back home and told us to continue with the antibiotics until the mono test comes out positive.

He is acting a bit better today (six days after onset). However, still running a fever at night 101.7 degrees and his swollen lymph node slightly came down in size but not completely. The inside of his mouth is still painful. He does not eat much or drink much. He has been complaining of his belly feeling weird and slept a lot yesterday.

We went back to our pediatrician for a followup today and our doctor suspects that he has mono due to his higher liver level but of course, we would need to confirm that for the real result. We are still told to take the Clindamycin until we hear back about the result.

I am just really concerned with his past infectious disease history. He was hospitalized with Kawasaki six years ago. And with his natural immunity so low I am concerned if the Clindamycin is doing more harm than helping him at this point. If I can turn back time, I should have asked the doctor to swab his throat before prescribing him the antibiotics but it is too late now. I cannot make him stop taking his antibiotics just in case he does havea bacterial infection. Is it possible to find out after taking his antibiotics halfway, to find out if he has the bacterial infection for sure?

And what should I do if the mono comes out positive? I am afraid to stop the medication in case he both had a bacterial and viral infection and make things worse by stopping the medication without any medical proofs that he should.

But I am also afraid to continue the medication in case he only has mono and the medication is making things worse on him. Would it? If he only takes the Clindamycin until Monday, which would be full seven days, is that sufficient treatment time for strep in case he had it too? I want to get your opinion on this. Please answer.



Welcome to

Here are the points I would like to bring across:

The lymph node is quite inflamed as per the picture (attachment removed to protect patient identity) that you sent. It may be inflamed in the event of any infection be it viral or bacterial.

Your reports are showing a high WBC (white blood cell) count with high neutrophils and also a high CRP (C-reactive protein) which is more suggestive of bacterial than viral infection. Hence the doctor was right in prescribing Clindamycin. However, since the infection load is very high maybe an additional drug may be required or we may need to change the drug based on the response.

Another last resort, if all fails, is to do a biopsy and find out what the lymph node actually contains. However, this is an extreme and painful step and should be reserved for the last.

As per what you are describing it may also be mononucleosis but even if it is mononucleosis you do not need to worry, it is self-limiting.

Continue the medications as advised.

Hello doctor,

Thanks for the reply. He now has red blood-shot eyes and small painful blisters on the corner of his mouth. I have not looked inside yet, he has pain opening his mouth and will not open the mouth for me. His lips appear to be more red than usual too. Does this sound much more like a viral infection to you at all? He is still running a fever. I will continue to give him the medication as advised since you explained a good reason for me to. Our doctor is suggesting that we stop giving him Clindamycin if the mono results come out positive. But as you said, since the reports say it is more likely to be a bacterial infection could it be possible that he has both bacterial and viral infection together?



Welcome back to

Yes, there is a possibility that there may be one infection superimposed on the other but it is less likely.

The blister may be due to the antibiotics. So, do not worry about it.

The pain in opening the jaw is due to the enlarged lymph node that may be pressing on the jaw.

Another possibility that we may be looking at maybe just plain mumps. However, the location that you have shown on the photo and the reports of sonography do not suggest so.

Again as I said if we need to be really sure what it is, we need to do a biopsy of the gland. Till then, we have to continue the same medications.

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