Recurrent fever

[Banoffeepie27]

Hi
my boy is 23 months old and has had a fever June, July and now August. One of those times he hit 40c, awake all night, floppy and refusing to drink, I did speak to 111 that night for advice, but nothing really came of it.
He gets a fever with no other symptoms, other than when it gets very high and he’s lethargic etc. calpol doesn’t seem to do a great deal either.
anyone else experienced this? I’m not sure whether to go to the dr about it as he seems to recover quickly?

How long do the fevers last?

@Banoffeepie27 did you get any answers for this? I was searching because my daughter is having similar episodes, 3 times in the last 5 months but not quite as regular every month as what you're describing. If it's regularly every month I read it could be periodic fever syndrome. We've been to the doctor several times in the last few months because her fever comes and goes over several days/weeks with no clear cause/other symptoms.
https://elpis-healthcare.com/blogs/periodic-fever-syndrome/

https://pmc.ncbi.nlm.nih.gov/articles/PMC5638471/