HAVE you heard the one about the horse that's allergic to grass.

The unlikely condition is making life a bit of a nag for an unfortunate filly called Bella.

Bella's owner, Lesley Richardson, noticed that the horse was breaking out in unexplained lumps and bumps after a day in the meadows.

Vets found that Bella was allergic to grass pollen - a rare condition known in medical circles as summer pasture obstructive pulmonary disease - and too much munching on her favourite food could kill her.

Bella can only be fed with specialised fodder.

Amazingly, the horse is following in her owner's footsteps - as Ms Richardson had to give up nursing 15 years ago when she developed multiple allergies which caused her to have severe reactions to everyday things.

Ms Richardson, 49, of East Boldon, South Tyneside, said: "When Bella developed the allergy she looked like the Michelin Man.

"Who would have believed a horse would be allergic to grass?

"We had to put a muzzle on her to stop her eating the grass. People kept taking it off her, so now we have had to put a tag on saying 'Do not remove'.

"I think people who saw her thought we were being cruel. But if she ate grass she could have a bad reaction or even die."

Ms Richardson knew Bella had a common dust allergy when she bought her ten years ago, and had to substitute hay or straw with wood shavings in the stable. But it was only years later that the full extent of the problem became evident.