Food coloring has been reported to cause anaphylactic reactions including rashes, swelling, and trouble breathing in some people. Food dyes can also trigger asthma.
Food coloring is used in a variety of foods.
Red food dye #2 (also known as carmine or cochineal extract) is actually made from dried insects (cochineal bugs) found in South America or the Canary Islands. Red dye #2 is the most widely recognized food dye allergy.
Yellow food dye #5 (tartrazine), and blue food dye #1 (Brilliant blue FCF), are also implicated in allergic reactions to food color additives. There are a number of other food dyes that have been noted to cause allergic reactions as well.
Reactions to food dyes are not IgE (true allergic type) reactions, hence difficult to diagnose by blood tests.
BLOOD TESTS FOR ALLERGIES
The blood test measures the amount of specific immunoglobulin E antibodies (IgE) to inhalants and foods in your blood. IgE causes histamine to be released when you’re exposed to various environmental and food allergens. The test is safer than a skin-prick test, as you’re not directly exposed to the allergen.
Results are graded from grade 0 (negative) and grade 1 (weak positive) to grade 6 (strong positive), depending on the level of the allergen’s specific IgE antibody in your blood. The higher the grade, the more likely it is you have an allergy to that allergen.
There’s a respiratory allergy screen, which tests for IgE to house dust mites, pet dander, pollens and mould spores, as well as a food allergy screening test which identifies allergy to cow’s milk, hen’s egg, wheat, codfish, soy and peanut. The seafood screen can detect allergy to various fishes.
Specific IgE tests can detect other allergens including some antibiotics, latex rubber, horse hair, bee and wasp venom and practically any allergies linked to raised IgE.
IGE BLOOD TESTS CAN’T TEST FOR ALLERGIES TO PRESERVATIVES AND FOOD COLOURING AS THESE REACTIONS AREN’T LINKED TO IGE.
In the past, ‘total IgE’ was measured as an allergy indicator, but this isn’t accurate as it may also be raised in parasite infections and with eczema. Total IgE may be raised in otherwise fit and healthy people with no allergies at all.
Sometimes very low levels of specific IgE are detected, which are usually ‘false positive’ results. The patient’s medical history can help identify these.