Can you be allergic to human hair? © Getty Images

Can you be allergic to human hair?

Human and animal hair are made of the same protein so do not cause an allergic reaction, but the sweat and saliva on animal skin cells can.

Asked by: Brandon Groocock (age 12)

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No. For that matter you can’t be allergic to animal hair, either. That’s because all mammal hair has the same basic chemical structure: it’s almost entirely made of the protein keratin. Our immune systems are exposed to the keratin in our own skin and hair continuously, so we never develop an allergic response to it.

Pet allergies are actually a reaction to substances in the animal’s skin cells, sweat and saliva (collectively known as dander) that get transferred to the fur during grooming. Animal dander is chemically different enough from our own sweat and saliva that our immune system treats it as foreign. Sometimes this results in an inappropriately strong reaction – an allergy. But humans are genetically so similar that we don’t have different dander compounds to each other.

A 2005 study at the National Institute of Environmental Medicine in Sweden, however, found that we can trap the dander from our pets in our own hair. So you can suffer an allergic reaction to an animal just by coming into contact with its human owner’s hair!

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