As winter approaches, it may be tempting to curl up under a thick feather pigeon, but experts have warned that it can lead to more than just hot tears.
Doctors have reported a case of "feather pigeon lung" – a pneumonia caused by breathing in dust from the feathers in bedding – and have urged doctors to be vigilant if patients come with unexplained breath.
The team says the condition, a form of hypersensitivity pneumonitis, is down to an immune response. Symptoms include night sweats, a dry cough and shortness of breath – repeated exposure to the cause can cause irreversible scarring in the lungs.
"Healthcare professionals are usually taught to ask patients with respiratory symptoms whether they have pets at home, such as birds, but, in the authors' experience, history does not usually extend to asking about spring coverings in quilts and pillows," they write. "This is an important omission because the use of feather, rather than synthetic, bedding is common."
Dr Owen Dempsey, consultant breast physician at Aberdeen Royal Infirmary and co-author of the report, said people would not rush to throw away their blankets and pillows, but take into account if they experienced respiratory problems when changing to spring bedding.
He added that although hypersensitivity pneumonitis appeared to be rare, and the report only covered one case of the spring pillow's lung, many cases may go unnoticed. "I suspect it's the tip of an iceberg," he said. "I think there are a lot of exposures out there that we are not aware of, and just because we are not aware of them they are ignored."
Dempsey and colleagues from Victoria Hospital in Kirkcaldy and Aberdeen Royal Infirmary, who wrote in the journal BMJ Case Reports, describe how a 43-year-old non-smoker went to his GP after experiencing three months of breathlessness, fatigue and discomfort.
His symptoms are down to an infection of the lower respiratory tract, but after a short improvement, worsened.
"Two months after the symptoms occurred, I couldn't stand or walk for more than a few minutes at a time without feeling like I was going away," said the patient – not named in the report. "Getting up in bed was a 30-minute activity because I could only handle two stairs at a time and then had to sit and rest."
The man's blood test results were normal and he received an X-ray on his chest. While this was reported as normal, he was severely short of breath and the GP referred him for a review of the respiratory clinics. Dempsey was concerned about the X-rays and pulled into the person's personal situation and was told that he had recently switched from synthetic to featherbed.
The man was asked to ditch the bedding, check his chimney and bird loft and make sure any mold in the house was treated.
Subsequent tests showed that the man had unusually high antibodies against special proteins from birds – including pigeons and parrots. In addition, further scans showed a pattern in the lungs suggesting hypersensitivity pneumonitis, while his lung function was significantly impaired.
Within a month of covering the spring's bedding, the man showed clear improvements and, with a subsequent course of steroids, felt well after six months.
The team says the most likely diagnosis was the feather pigeon kid. The condition, they say, is a rare subgroup of "bird fan lungs" – itself a form of hypersensitivity pneumonitis – caused by exposure to feathers and droplets. Other forms of hypersensitivity pneumonitis include "farmer's lung", "bagpiper's lung", "paprika slicer's lung" and even "mummy-handler's lung", reflecting the wide range of activities which have been linked to breathing in substances that can cause severe pneumonia.
"There are hundreds of different types of hypersensitivity pneumonitis," Dempsey said. "For doctors, it is really important to be curious and take a careful history and ask people about exposures because there are many things that people do that we do not always appreciate when we sit in a clinic or surgery."