An allergen is anything that causes an allergic reaction, such as certain foods. People can be allergic to almost any food, but for labelling purposes the most common food allergens are known as “priority” or “major” allergens. There are different ways to come in contact with a food allergen, such as: eating, touching and in rare cases, inhaling the food protein. Contact with the nose and eyes can also cause a reaction. Understanding how to avoid contact with a food allergen will help prevent allergic reactions.
Oral ingestion (mouth)
Eating an allergen causes most serious reactions. Other ways that allergens could be ingested are through saliva (e.g. kissing) or cross-contamination.5 Even ingesting a small amount of a food allergen can cause a reaction. Most of these reactions can be prevented by reading labels and taking steps to prevent cross-contamination.
Skin contact (touch)
Skin contact can cause hives or other skin symptoms where the allergen touches the skin. In most cases, healthy skin does a good job of keeping allergens out of our bodies, and serious reactions from skin contact are rare.6 7 If an allergen comes in contact with skin, wash it off to decrease the chance that it will accidentally get into the mouth, eyes or nose (where it can possibly cause a more serious reaction). This is why washing hands before eating or touching the eyes, nose or mouth is important.8 Keep in mind that people, especially young children, frequently touch their mouths, as well as their eyes and nose. 9 10
Inhalation (breathing in)
In some cases, allergic reactions can happen when food proteins are inhaled through the air, such as:
- In steam from cooking food (e.g. sizzling fish)
- When food in a powdered form is released into the air (e.g. blowing powdered milk)
- When small amounts get into the air when food is crushed or ground (e.g. tree nuts). 8
These reactions are usually mild, but in rare cases people have had severe reactions.6 8 11
The smell of a food alone cannot cause an allergic reaction. The smell is caused by volatile organic compounds (VOCs), which are not proteins.
Teaching Children
Here are some simple rules to teach your child and things for them to keep in mind:
- Wash your hands before eating or touching your nose, eyes or mouth.
- Only eat food that is made for you. It’s not safe to share food.
- Don’t share spoons, forks, knives, cups, bottles or straws.
- If you get an allergen on your skin, ask an adult for help, clean it off and wash your hands.
Make hand-washing fun for young kids – sing a song that lasts about 30 seconds.
References
5. Maloney, J.M., Chapman, M.D., and Sicherer, S.H. “Peanut allergen exposure through saliva: Assessment and interventions to reduce exposure.” The Journal of Allergy and Clinical Immunology 118.3 (2006): 719-724.
6. Simonte, S.J. et al. “Relevance of casual contact with peanut butter in children with peanut allergy.” The Journal of Allergy and Clinical Immunology 112.1 (2003): 180-182.
7. Wainstein, B.K. et al. “Combining skin prick, immediate skin application and specific-IgE testing in the diagnosis of peanut allergy in children.” Pediatric Allergy and Immunology 18 (2007): 231–239.
8. Kim, J.S. and Sicherer, S.H. “Living with Food Allergy: Allergen Avoidance.” Pediatric Clinics of North America 58.2 (2011): 459-470.
9. Tulve, N. et al.“Frequency of mouthing behavior in young children.” Journal of Exposure Analysis and Environmental Epidemiology 12 (2002): 259–264.
10. Nicas, M., and Best, D.J. “A study quantifying the hand-to-face contact rate and its potential application to predicting respiratory tract infection.” Journal of Occupational Environmental Hygiene 5.6 (2008): 347-52.
11. Roberts, G., Golder, N. and Lack, G. “Bronchial challenges with aerosolized food in asthmatic, food-allergic children.” Allergy 57.8 (2002): 713-7.
5. Maloney, J.M., Chapman, M.D., and Sicherer, S.H. “Peanut allergen exposure through saliva: Assessment and interventions to reduce exposure.” The Journal of Allergy and Clinical Immunology 118.3 (2006): 719-724.
6. Simonte, S.J. et al. “Relevance of casual contact with peanut butter in children with peanut allergy.” The Journal of Allergy and Clinical Immunology 112.1 (2003): 180-182.
7. Wainstein, B.K. et al. “Combining skin prick, immediate skin application and specific-IgE testing in the diagnosis of peanut allergy in children.” Pediatric Allergy and Immunology 18 (2007): 231–239.
8. Kim, J.S. and Sicherer, S.H. “Living with Food Allergy: Allergen Avoidance.” Pediatric Clinics of North America 58.2 (2011): 459-470.
9. Tulve, N. et al.“Frequency of mouthing behavior in young children.” Journal of Exposure Analysis and Environmental Epidemiology 12 (2002): 259–264.
10. Nicas, M., and Best, D.J. “A study quantifying the hand-to-face contact rate and its potential application to predicting respiratory tract infection.” Journal of Occupational Environmental Hygiene 5.6 (2008): 347-52.
11. Roberts, G., Golder, N. and Lack, G. “Bronchial challenges with aerosolized food in asthmatic, food-allergic children.” Allergy 57.8 (2002): 713-7.
