Nearly 3 year old suddenly unsettled during the night - seperation anxiety ??

[sazlocks]

DS1 is 3 in Jan and for the last couple of weeks has started waking in the middle of the night and screaming. When one of us goes in its usually for a random thing - need a tissue, lost my monkey etc etc
The first night we went in and out to him for about 3 hours ! We have tried leaving a light on but that hasn't helped.Tried leaving him to cry after an initial visit but that tends to wake his 10 month old brother.

He didn't sleep through until he was 12 months old and ever since then has been great. He has gradually dropped any naps in the day and only now sleeps when he is really knackered. He goes to bed between 7 and 7.30 - has had the same routine forever. Nothing else has changed day to day. I wonder if there is a seperation anxiety phase at this age ?

i don't know but ds1 does this now and again
normally he doesn't cry, he just comes into our bed. we grunt at him, he falls asleep and then if one of us is still awake we put him back to bed, otherwise we all just sleep there

he goes through phases of it where he;ll do it for a few weeks and then stop suddenly. doesn't happen that often

threadworm?

Thanks.
Threadworm - hmm - didn't even think about that - he hasn't been complaining of being itchy or anything but will have a look.