The worst of DS4's (4.3y AS) behaviour is caused by him feeling that hes not being listened to. DS2 &DS3 are the worst culprits in our house, at not listening to him and DS4 turns into a screaming, kicking, whirlwind banshee at that point!
DS4 also has problems with clothing - he cant cope with motifs that have webbing on the inside: plastic-y motifs that make the garment stiff: piping which makes extra 'seems': and socks altogether! Hes turned into a bit of a stripper at home
He also has problems with being touched, i really do think that it feels like we are punching him when we lay a hand on him to 'steer' him out the way. which we just dont do anymore, we have to ask him instead, takes 4 times longer but at least it avoids the screaming, flapping and whirling!
DS5 (3.2y autism, non-verbal) also has similar problems, and has to have his pyjamas altered (hes still in babygros to stop him removing his nappy) - it took a long time to realise that he couldnt cope with feet in his babygrows, many sleepless nights we all had until we figured that one out!
DS1 (ADHD) had problems with clothing for many years, would only wear certain items, hes now 17 and much much better (with clothing anyway )
I think my point is that many children on the spectrum have very similar problems but display in a different way, its working out whats causing the problems is the key, rather than trying to elimanate the effects.
Im guessing that if your DD isnt a naturally violent person and its only a recent problem, then there is something bothering her, that is fairly recent causing such stress that she feels the only way to deal with it is to hit out. If she has got to the point of being so stressed, she probably wont be able to tell you whats upsetting her. Ithink routine is definately the first place to start - especially as the holidays provide none, and even if its not the lack of routine that is upsetting her, then providing one should show whats upsetting her. spend time watching and being in 'tune' with your DD, then you will start to see a pattern of when undesirable behavior arrives, whats causing it, and how to avoid it.
Good luck