Word from the “who knew?” department: “The advice for allergy sufferers to avoid feather pillows is not supported by scientific evidence,” says Sam Arbes, an allergen specialist at the National Institute of Environmental Health Sciences. To wit:

No studies have found synthetic pillows to be better than down for allergy or asthma sufferers, though several have suggested the reverse, says Rob Siebers of the Wellington Asthma Research Group, in New Zealand, who has studied the subject for a decade.

Feather allergies are rare. Adverse reactions to down pillows seem to be attributable to dust mites (found in any kind of pillow).

Tightly woven cases, often used with down pillows, help keep out dust and dust mites.

Allergy experts’ bottom line: People with allergies or asthma shouldn’t put anything on their beds that can’t be washed weekly in hot water (130 degrees F). And they should cover the pillows, mattress, and box spring with allergen-impermeable covers, so what’s inside should not be a factor.