Q: My daughter, who’s 7 years old, has dairy and other allergies and asthma, and has had one anaphylactic reaction. Then last fall, she broke out in big welts on her arms where another child’s milk spilled on her. (She did not get wheezing.) Is it possible to get anaphylaxis from skin contact with an allergen, without consuming it? We gave her antihistamines, but should I have used the epinephrine auto-injector?
Dr. Sicherer: It is very unlikely for skin contact to trigger anaphylaxis. Those with severe allergies are frequently exposed to the allergen on the skin during skin prick tests. In a review of a database of 34,905 skin tests to foods in 1,138 patients, the systemic reaction rate was 0.008 percent – with no severe reactions.
Sometimes small hives develop around the area of a skin test, not just at the skin test itself, presumably because of some localized spreading. But reactions beyond the skin remain rare.
Our team and others have applied peanut butter to the intact skin of children with significant peanut allergies, and none had reactions beyond the site of application, and most had no reaction at all.
There are, however, reports of cases of reactions attributed to skin exposure where symptoms occurred beyond the area of skin exposure. The cases primarily describe very young children, and some ingestion could not be ruled out.
It’s reasonable to assume that anaphylaxis from skin exposure is rare because the skin barrier prevents the protein from entering the blood system. Therefore, modest exposures on intact skin should not result in anaphylaxis.
Symptoms beyond the skin may be more likely if a large amount of protein is applied to large areas of non-intact skin, for example, skin with eczema rashes. Such exposures would be unusual (big splashes that soak clothing, etc.).
Regarding your child, if it was clear that the exposure was only to the skin, and the symptoms were only on the skin, and not progressing or involving other parts of the body, then giving an antihistamine alone and cleaning the area seems reasonable. Epinephrine would be warranted if the symptoms were progressing.
Dr. Scott Sicherer is Chief of the Division of Allergy and Immunology of the Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai in New York. Together with Dr. Hemant Sharma, Associate Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington, he writes “The Food Allergy Experts” column in the American Edition of Allergic Living magazine. Questions submitted below will be considered for answer in the magazine.