Curl up under a thick duvet in the coming winter nights may not be as harmless as many think. At least not after a group of doctors from the Aberdeen Royal Infirmary in Scotland reported for the first time a case of “feathered pneumonia”, a lung inflammation caused by the inhalation of dust from the feathers that stuff blankets and pillows. Experts urge colleagues to remain alert if patients present with an unexplained respiratory difficulty.

The doctors, cited by the Guardian , believe that a form of hypersensitivity pneumonia depends on an immune response. Symptoms include night sweats, dry cough and shortness of breath: repeated exposure can also create irreversible scarring of the lungs. “Health care professionals are generally taught to ask patients with respiratory symptoms if they have pets at home, such as birds. But according to our experience, it usually does not extend to feather feathers from duvets and pillows,” the researchers write . “This is an important omission because the use of non-synthetic bed linen is common,” they add.

Owen Dempsey , author of the study reported by the BMJ Case Reports , has specified that it is not necessary to throw away duvet and pillows at all, but to take note of any respiratory problems when switching from synthetic bed linen to one in feather. Because, even if doctors have only documented one case, many others could go unnoticed.

The first documented case concerns a 43-year-old non-smoker man who went to the doctor after spending 3 months with breathlessness , fatigue and discomfort. The symptoms were due to an infection of the lower respiratory tract, but after a brief improvement it started to get worse again. “Two months after the onset of symptoms, I was unable to stand or walk for more than a few minutes at a time without feeling like I was going to faint,” says the patient.