Allergies...cytopoint/apoquel/advocate

Hi guys,
Our staffy girl is 9 months old. Due to allergies, she had a cytopoint injection just over 4 weeks ago. It worked great and then 3 days ago she had her usual advocate flea treatment. A day later, she had a flare up. Mainly her ears, but they have become infected. We took her to the vet today and she had another injection and was prescribed Surolan.
As I’m sure you’re probably aware, the injections cost a lot! We changed her food and treats to hypoallergenic ones a month ago and have been really strict with that.
I’m wondering if perhaps it was the advocate (it happened last time a few days after the treatment too). We’re planning on changing her flea treatment next month.
However, the vet suggested that if that doesn’t work we might like to try apoquel as an alternative. I’ve done a quick search online and I don’t like the sound of it too much!
I’ve seen piriton mentioned a few times and wondered if anyone here has any opinions.
It’s so awful seeing her tormented by the itching and the scratching, and whilst the injections are great, they are financially a massive burden. A burden that obviously, with no other solution we will take on.
Any advice would be great.
Thank you,
Edie’s mummy

Just had a quick Google
Do not use APOQUEL in dogs less than 12 months of age or those with serious infections. APOQUEL may increase the chances of developing serious infections, and may cause existing parasitic skin infestations or pre- existing cancers to get worse! The side effects don't look very pleasant either! Do you know what causes the irritation in your girl other than the advocate?
I give Katy antihistamine in the summer for grass rash!

Hi Jenc,
No, we really don’t know. She didn’t seem to have any reaction to anything before the age of about 6/7 months.
We changed her food to hypoallergenic as the vet said she thought it seemed more likely a food allergy. It was going so well, until we used the advocate again. As soon as we put it on her, her eyes and muzzle got red. The itching started the next day and then the ear problem followed.
I think we will give apoquel a miss! I wasn’t sure if mentioning antihistamine to the vet was a good idea... Almost like I didn’t want to tell her how to do her job, nor tell her that the monthly injection cost was quite beyond us.
Thank you so much for your reply. Can I ask what antihistamine you give Katy (who, by the way, looks a lot like my girl!)

Katy never had any reactions to food but is on hypo allergenic food as I prefer not to have all the fillers of grain & rice that they put in the food as fillers!
Advocate can have these reactions
What are the risks associated with Advocate? In both cats and dogs, the most common side effects are local reactions at the site of application, such as temporary itchiness, and on rare occasions, greasy fur and redness of the skin. Vomiting has also occurred rarely. These signs disappear without further treatment.
I just but Tesco's own antihistamine & they work fine
Pop up a pic of your girl