It may sound odd, but allergies to cardboard are not uncommon. They are recognised as a form of allergic contact dermatitis. Cardboard allergies are most common among people who work with cardboard, but they can affect anyone.
Cardboard allergies are a type of contact dermatitis. This is an inflammation of the skin. Symptoms include flaking of skin, redness, blistering and itching. Contact dermatitis is caused when the blood cells become sensitised to substances in the environment.
People with allergies to cardboard are not allergic to the cardboard itself, but to an adhesive resin used in the manufacture of cardboard. This resin is called P-Tertiary-butylphenol formaldehyde resin (PTBP). It is also used to make plastics, plywood, varnish and some leather products. People with cardboard allergies are sometimes also allergic to shoes and plastics that contain PTBP.
To have a cardboard allergy, a person must have been exposed to the substance. People who work with cardboard every day are more at risk. On exposure, a red, itchy rash usually develops within 6 to 12 hours. The reaction will get worse over the next 48 to 72 hours, and eczema (scaly, weepy skin) may develop.
The allergy can be identified by a patch test. PTBP is one of the allergens usually tested for on a patch test. Once identified, it can often be treated with antihistamines and corticosteroids. The best way to treat cardboard allergies is to stay away from cardboard and any other substances containing PTBP.
People who are strongly allergic need little contact with cardboard or PTBP for a reaction to occur.