SATURDAY, Oct. 1 (HealthDay News) -- Halloween candy may contain some obvious allergens, but there are many more unexpected allergy and asthma triggers that can pose a threat to trick-or-treaters, including dusty costumes, fog machines and makeup, according to experts from the American College of Allergy, Asthma and Immunology (ACAAI).

"When people think of Halloween-associated allergies, they focus on candy and often overlook many other potential triggers," said Dr. Myron Zitt, former ACAAI president in a news release. "By planning ahead, you can ensure not only safe treats, but also safe costumes, makeup, accessories and decorations."

The ACAAI advised parents to be on the lookout for six potential allergy and asthma triggers they may not be expecting, including:

• Gelatin. Although it's a less common trigger, research published in the Annals of Allergy, Asthma and Immunology shows gummy bears and other candies may contain this potential allergen. Parents can have their child tested for specific allergies and develop a food allergy treatment plan. They may also want to have some non-candy treats, such as stickers or small toys, on hand to swap for candy.
• Nickel. Costume details and accessories, such as belts, tiaras and swords may contain nickel -- one of the most common causes of allergic contact dermatitis, which can make skin itchy.
• Dust mites. Old costumes packed away in attics or closets may be filled with dust mites, which trigger asthma and allergies. Parents should either buy or make new costumes or wash old ones before kids put them on.
• Makeup. Some types of face and body makeup may include preservatives that may cause allergic reactions. Buying higher quality theater makeup can help avoid this trigger. Also be sure to test the makeup on a small patch of skin before applying it over a larger area of skin at least a few days before Halloween.
• Fog. Real fog or fog machines can trigger asthma in some people.
• Pumpkins. Allergies to pumpkins are rare, but they can develop suddenly -- especially when they are moldy or dusty. As a result, pumpkins purchased at a grocery or discount stores are less likely to trigger an allergy.

More information

The U.S. Centers for Disease Control and Prevention provides more information on asthma in children.