Allergist members of the American College of Allergy, Asthma and Immunology in Arlington Heights, Ill., warn costumes, make-up, dyes and decorations often contain common allergens such as latex. Ingredients in these products can also trigger asthma or cause a delayed itchy skin reaction called contact dermatitis in some.
In addition, cold weather, running from house to house and allergens such as mold spores hiding in piles of leaves can also cause asthma symptoms to flare up, the allergists say.
The experts suggest parents of children with allergies may wish to consider forgoing trick or treating altogether in favor of a party or haunted house where the food and activities can be controlled.
Those going out need to take along emergency medicines such as quick-relief inhalers or injectable epinephrine in case of a severe reaction should be.
"Children with severe allergies or severe asthma also should wear medical alert identification bracelets or chains stating their diagnosis," Dr. James Sublett, spokesman for the ACAAI, says in a statement. "This will help speed treatment in case of an emergency."
The allergists also suggest keeping an eye on so-called "fun-size" treats, which may not be made with the same ingredients or in the same facility as the full-sized treats that are allergen-free.