Have you ever been tempted by a bright blue shaved iced dessert or a bunch of fluffy blue cotton candy? Food coloring is used to make all kinds of treats — including candy, baked goods, and hamburgers — look extra tasty. But could food dyes also be causing your allergies?

Some MyFoodAllergyTeam members say food dyes are making them sick. “An allergy to blue and yellow food dyes caused a breakout of rashes all over my body from knees to neck,” one member said. Another replied, “If I consume food or drinks that have red dye, my face and eyes swell and progressively get worse.”

Reactions to food dyes can occur exist, but fortunately, they are rare. Blue food dye is one type of dye that can sometimes cause allergic reactions. Read on to learn five facts about food dyes and allergic reactions.

1. Artificial Food Dyes Could Be Causing Your Allergies

Food dyes come in two different types: natural and artificial. Natural dyes come from natural sources, like plants and animals. Examples of natural food coloring include carmine, a red dye that comes from insects, and annatto, a yellow dye that comes from a seed.

Artificial dyes are created from combinations of chemicals. The U.S. Food and Drug Administration (FDA) has approved nine artificial food dyes:

• Blue 1 — Also called Blue No. 1 or Brilliant Blue FCF
• Blue 2 — Also called Blue No. 2 or Indigo Carmine
• Green 3 — Also called Green No. 3 or Fast Green FCF
• Red 2 — Also called Red No. 2 or Amaranth
• Red 3 — Also called Red No. 3 or Erythrosine
• Red 40 — Also called Red No. 40 or Allura Red AC
• Yellow 5 — Also called Yellow No. 5 or Tartrazine
• Yellow 6 — Also called Yellow No. 6 or Sunset Yellow FCF​
• Orange B

2. Blue Food Dyes May Cause Allergies

Blue 1 and Blue 2 are the two blue dyes approved by the FDA for use in food.

Blue 1 is used most often in cereals, juice drinks, sodas, and ice cream. It is made from oil, although it used to be made from coal tar. It can cause allergic reactions.

Blue 2 is the synthetic version of an indigo dye. Common foods that contain Blue 2 include:

• Baked goods
• Cereals
• Snack foods
• Candy
• Maraschino cherries
• Sausages
• Ice cream and sherbet
• Dairy products

It has not been found to cause allergic reactions, although some animal studies suggest it may be linked to cancer.

3. You Can Find Artificial Food Dyes in Ingredient Lists

The FDA requires food manufacturers to list artificial food colorings that are chemically manufactured by name in ingredient lists. For example, if a food product contains Blue 1, “Blue 1” must be listed. If the ingredients list contains “artificial colors” or “color added,” it means that naturally derived food coloring has been used.

To avoid synthetic food dyes like Blue 1 and Blue 2, it’s a good idea to choose foods that are certified organic by the FDA. These foods cannot contain any artificial food dyes. However, foods that are “made with organic ingredients” are not necessarily all organic and may contain artificial dyes.

4. Food Dye Allergies Are Different From Food Sensitivities

If you have symptoms after eating food that contains dye, you may not be allergic to the dye. You could have food sensitivity. If you have a food dye sensitivity, you may experience gut symptoms like gas, diarrhea, heartburn, and vomiting after eating food that has dye in it. You might also feel tired and cranky. The more of the dyed food you eat, the worse you will feel. It’s good to know that food sensitivities aren’t life-threatening.

Food allergies cause your immune system to react to a threat. If you’re allergic to food dye, it means your body has produced antibodies to fight the dye. This can create symptoms that don’t only affect your gut, like hives, headaches, and flushing. Your head might hurt, and you might feel dizzy and itchy and have difficulty breathing.

Food allergies can cause a life-threatening condition called anaphylaxis. Anaphylaxis causes blood pressure to drop and closes off your airways, making it hard to breathe. Without an injection of epinephrine, anaphylaxis can be fatal.

Unlike food dye sensitivities, which get worse if you eat more food dye, food dye allergies can be triggered by any amount of food dye ingested, depending on how strongly a person’s immune system reacts.

5. You Can Test for Food Dye Reactions

If you’re having reactions to certain foods but aren’t sure if food dyes are the cause, try keeping track of what you eat every time you notice symptoms. One MyFoodAllergyTeam member said “Keep a food diary to find your allergies. Try to rotate foods so you eat them four days apart and see which foods are cross-reactive. Keeping a food diary helped me the most.”

Skin testing isn’t a great way to test for reactions to food dyes. The usual method of testing for allergies to food dyes — or to any food additive — is an “oral challenge” or a “food challenge.” During this test, you will sample different food additives in the safety of an allergist’s office. If any reaction is observed, the allergist will quickly and safely treat you.

If you’ve had reactions to food with additives before, the oral challenge method of testing can help you figure out exactly which food dye is causing the reaction or if another food additive is the cause. It can be especially helpful with food dyes, as several food dyes are often used in a product at once.

If you think you might be sensitive or allergic to food dyes, talk to your allergist. They can help you get tested for food dye sensitivities or allergies.

Find Your Team

MyFoodAllergyTeam is the social network for people with food allergies and their loved ones. On MyFoodAllergyTeam, more than 41,000 members come together to ask questions, give advice, and share their stories with others who understand life with food allergies.

Have you had problems finding which food dyes are in the products you buy? Have you experienced sensitivity or allergies to food dyes? Have you talked to your allergist or other health care provider about trying an at-home food sensitivity test? Share in the comments below, or start a conversation by posting on your Activities page.