My boxer pup unknown allergy

Question
I have a 6 month old  white male boxer who over the last 3 days has deveolped an allergy.
He was let in from the garden after going for pee at night after 5 mins with a swollen pink face and lumps all over his body.
As the vets was not opened yet i gave him half a Pirton tablet which seemed to relieve it slightly.
The vet said he had either been bitten or was allegic to something in the garden and gave him a steriod injection.
The lumps gradually went down, but by 12 oclock that night after going out for a pee in the garden the lumps reappeared but his face was more swollen this time.

I called the emergency vet who advised to give him a full Pirton tablet and this done the trick.
It has happened a couple of times since, he is walked twice a day without any reaction but as soon as goes in the garden it flare up.
There is nothing but grass in the garden no plants any ideas? Could he have devolped a allergy to grass?

Thanks, Joanna

Answer
Hi Joanna,

How strange!  Are you positive there's been no fertilizer or other chemical treatment placed on the grass?  If you can rule out anything in the garden, aside from the actual grass, then yes, it's possible he's developed an allergy.

My female used to break out in hives when she went out in the freshly mown or wet grass.  Is he breaking out during the day after a trip to the garden?  Just at night?  Can you determine if the dry grass breaks him out or if it's just wet?

I'd have him on lead the next few nights and let him walk you to the spot he goes, that way you can see if he's going to a specific area and be positive there's nothing there he's getting into.  (Hedgehog nest, etc.)

The good news is, if it IS the grass, my girl eventually grew out of the 'allergy'.  Hopefully your boy will as well.