An animal at HorseWorld near Bristol, with an allergic reaction to midge bites, needs a protective pair of pyjamas to ease its suffering.
The charity, Horseworld, near Bristol says Gracie May's condition has worsened. It wants help to make a special pyjama suit.
Many horses which suffer from the condition wear rugs to try and prevent the bites.
HorseWorld is now appealing for help from rug sponsors or machinists who could help to create a special suit for the 17 hands high heavy horse.
Karen Hardwick, from the charity said:
"We have been struggling to keep Gracie May's itching under control.
"She currently has a rug that protects her when she is outdoors in the fields, but it's far from being a perfect fit and tends to rub against her. She badly needs something suitable for wearing indoors when she is in her stable here at Whitchurch, a pyjama suit would fit the bill.
"Her size is an issue too. She measures seven feet high from the ground to the top of her head. We've searched high and low but can find nothing on the market that would fit this gorgeous heavy horse."
Gracie arrived at the charity centre, which rescues, rehabilitates and rehomes horses, ponies and donkeys, emaciated and with hair missing in 2001. She has been nursed back to health and now lives at HorseWorld's visitor centre.