I have twins, both diagnosed, and they both have MAJOR sensitivities and some are due to sounds of things. The question I would have for you is...is it ALL fans? For eg. do ceiling fans evoke the same response? IF they do, it may be sound. IF they do not, maybe another factor. One thing I learned many years ago that has stuck with me is this....I was at a workshop and a parent had shared with the group that their child all of a sudden had developed a phobia with the kitchen and he was deathly afraid of it. They went through the whole gammet of what it could be...eventually the son shared with them that the banana plant (the family had received) was trying to murder him. This stuck with me because we always try and figure these things out through "our" type of logic and eyes....but sometimes we may need to think things out through their eyes.

Best wishes to you.

When my son started to see an OT he started to be less bothersome by certain sounds & touches. OT's have things like a rice box they use to help with sensory issues, weighted vest, balls, & many other items they use to help your child.
When my son was around 3 he told us rain hurts, the sun was too bright, snow was scratchy which made it very hard on us to get him outside. We read some of Temple Gradin's books on sensory issues & that helped out & once we where pointed in the direction of an OT that help our son who is doing so much better now.

if it is oscillating fans it may not be the sound. Some Autistic children see a level we can't such as florescent lights. An Autistic teacher once solved a very confusing problem for me by telling me this. Our son reacted to going into stores by screaming, we came out he stopped. Didn't matter if we were in the mall or outside shopping. She explained that some children can see the flicker of the florescent lights and it hurts their eyes. Go figure:( It is apparently a faster version of the flicker it does just before the bulb is about to go and we know how annoying that is, can you imagine seeing that all the time? So, it may be he can see the fan oscillating where we can't and it is hurting his eyes and head not his ears? Just a thought:)

is your daughter working with an occupational therapist? ,that is going to help her a lot ,... it may be sensory auditory problems . ..

I took my daughter Jordan who's 13yo now on vacation to see friends. They had two younger, very loud and liked to fight, kids. Jordan is very sensitive to sound and emotions. She had many breakdowns throughout the week......until my friend's husband handed her ear plugs he used when shooting. She put them on and has worn them everyday since! I decorate them to match her outfits and wears them around her neck like an accessory. She can use them when she needs them and it has opened up her whole world!