Hair loss after neutering

I have a 3 year old male cat which I took in from the streets about 4 months ago. We got him neutered 3 months ago and he finally now stopped spraying. However at the time he stopped spraying he started to lick himself intensely and has bolt patches on is back and end of tail. He also has a lot of nasty abrasions on his skin mostly in the bold patches.:cry: We had him examined by the vet who thought he might have a food allergy (he is now on food trial since end of April) and treated him with antibiotics for the abrasions which he thought were some sort of dermatitis. The treatment is over and he still gets fresh abrasions. Could he do these to himself by pulling out patches of hair (we do find a lot of hair patches) Could this behaviours be hormonal due to neutering, since it started once he stopped spraying? I also think it might be pollen. Has anyone had problems like this before?
Thanks Ally

What is the food he's eating now, and what was he eating before (brand, flavour, wet, dry)?

Any possibility of fleas? Some cats can get severely allergic to even just one bite.

I like sugarcatmom's idea of possible flea allergic dermatitis(FAD). The site of hair loss and itching would support this. However food allergy, contact irritation, etc. could also cause this.

There is no direct link with the neutering. Decrease in testosterone will not lead to itching and hair loss. :cat: