November 04, 2026 | Black & Kletz Allergy
Can someone have an allergic reaction when exposed to another person’s hair? Is there such thing as human hair allergy? Well, a true allergy to the hair itself is extremely unusual, and evidence for it is very limited. Human hair is primarily made of a protein called keratin. Keratin is also found fingernails, toenails, the outer layer of skin, animal hair/ fur/feathers (although there are some minor additional proteins in animals). As a general rule, our immune systems are exposed to the keratin in our own skin and hair continuously, so we never develop an allergic response to it. There have been reports of reactions associated with human hair exposure, but a well-established clinical allergy to ordinary human hair keratin is not something commonly recognized and is not acknowledged as a fact in the field of allergy and immunology.
Pet allergies are actually a reaction to substances in the animal’s saliva, sweat, and skin cells, (collectively known as dander) that get transferred to the hair or fur during grooming. Animal dander is chemically different enough from our own sweat and saliva that our immune systems treat it as foreign and as a result, may cause an allergic reaction.
One interesting tidbit: A 2005 Swedish study at the National Institute of Environmental Medicine found that individuals can trap the dander from our pets in our own hair. This means that one can suffer an allergic reaction to an animal just by coming into contact with the human owner’s hair.
In theory, proteins associated with hair could trigger an immune response in a sensitized individual, although true allergy to human hair itself is poorly documented. So, if being allergic to human hair is essentially unheard of, why do many people complain of allergic reactions to their hair. It so happens that many reactions blamed on human hair are actually caused by substances on the hair as opposed to the hair itself. Some of the causes are listed below:
Hair Products – Shampoo, conditioner, perfume, hairspray, and styling products can leave chemicals on someone’s hair. Another person may react to those ingredients.
Hair Dye Residue – Ingredients such as paraphenylenediamine (PPD) can cause allergic contact dermatitis. Residue or a transferred product may expose someone else to this chemical.
Synthetic Hair – Hair extensions and wigs may contain dyes, acrylates, and other chemicals that can cause allergic skin reactions.
What are the symptoms of an allergic reaction to substances used on the hair or to synthetic hair?
- Itchy skin after touching hair
- Redness or hives on the hands, face, and/or neck
- Periorbital swelling (i.e., swelling around the eyes)
- Itchy or irritated scalp
- Eczema-like rashes
- Occasional more serious symptoms
What tests might an allergist perform:
- Patch Testing – Checks for delayed-type allergic reactions (Type IV allergic reactions) to chemicals and other contact allergens. The best test for typical hair care-related allergic reactions.
- Skin Prick Testing – Investigates certain immediate-type allergic reactions (Type I allergic reactions)
- Specific Testing – May investigate a suspected substance or protein with one’s actual hair care products, when appropriate. This is typically performed by patch testing.
There is not a routinely established standard allergy test for ordinary human hair itself particularly, as mentioned above, because it is uncertain if a true allergy to human hair even exists. Interestingly however, an individual may potentially react to another person’s hair without reacting to their own hair products or their own hair. For example, one might develop a rash after hugging someone whose hair contains a particular fragrance or styling chemical, but that does not necessarily indicate that they are allergic to that individual’s hair.
The board certified allergists at Black & Kletz Allergy located in the Washington, DC, Northern Virginia, and Maryland metropolitan area will readily answer any questions you have regarding allergic reactions to “hair” or hair care products. We also diagnose and treat other types of contact dermatitis such as itching and rashes from cosmetics, skin care products, adhesives, metals, latex/rubber, shampoos, conditioners, fragrances, and plants (e.g., poison ivy, poison sumac, poison oak). We have 3 offices with locations in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. All our offices offer on-site parking. In addition, the Washington, DC and McLean, VA offices are accessible by Metro. There is also a free shuttle that runs between the McLean, VA office and the Spring Hill metro station on the silver line. Please make an appointment by calling any one of our 3 offices, or alternatively, you can click Request an Appointment and we will respond to your request within 24 hours by the next business day. Black & Kletz Allergy diagnoses and treats both adults and children and we are proud to serve the Washington, DC metro area residents for which we have done for more than 5 decades.
