Farmers are being affected by a mysterious new skin disease, dermatologists report.
Affected farmers have blisters on their ears (Copyright Blackwell Publishing)
The condition affects the ears, which become hot, itchy and sore before blistering and crusting.
A study in the British Journal of Dermatology found it only occurs during lambing season, which lasts up to three months, but the cause is unclear.
The researchers from Southampton believe "lambing ear" may be a problem associated with indoor farming.
George Heathcote, a farmer from Hampshire and one of the study's authors, had consulted doctors at Southampton General Hospital after experiencing blistering on his ears, which he was convinced was linked to lambing.
Mr Heathcoate decided to write a letter to Farmers Weekly magazine to find out how many other farmers had the condition.
A total of 69 responded, all of whom said the condition only occurred during lambing or calving.
But similar letters in farming magazines in Australia, New Zealand and the Falklands found no one in those countries who seemed to be affected.
Dermatologists at Southampton carefully assessed five patients with the condition, which had not been previously reported in medical journals or textbooks.
They could not explain what was causing the blisters although they found the condition was very similar to a rash which can occur in children due to a "sunshine allergy".
However, most of the farmers with the condition did lambing indoors and there was nothing unusual about the lighting in the sheds. As the disorder only occurs during lambing, it may be something to do with the practice itself, the researchers believe.
Professor Peter Friedmann, consultant dermatologist at Southampton General Hospital, said: "During shearing, which takes place in May or June and may be indoors or outdoors, the same farmers who suffer lambing ears can shear the sheep with no symptoms at all.
"This suggests that bodily fluids from the sheep, such as amniotic fluid, sac and placenta, or chemicals used as part of the process, play a part, although intriguingly, the disorder does not affect the hands, which have maximum contact with fluids and products involved in lambing."
He added in Australia, New Zealand and the Falklands lambing occurs outdoors with little intervention from farmers which may explain why the condition does not occur there.
Nina Goad of the British Association of Dermatologists said the study showed how dermatologists were coming up against new conditions on a regular basis.
"Following foot and mouth and blue tongue, the discovery of a disease affecting the farmers themselves may seem like an extra blow.
"However, it is actually positive that the disorder has been identified and can now be shared with dermatologists across the UK, as it will allow for more research and shared knowledge."