IRRITANTS AND ALLERGENS
Ingredients causing irritation and allergies
Substances that cause irritation and allergies can be found in all types of beauty, personal care and household products. Most people will sometime during their life encounter chemical ingredients that cause sensitized skin or irritation on skin or in eyes.
But not all irritations caused by products are allergic reactions. A hypersensitive person can have the same symptoms as an allergic person. The difference is that an allergy is connected to the immune system while an irritation is local.
In an allergic reaction from a product, the immune system is triggered by a substance and the body reacts by for example developing eczema, itches or pain.
High and low level exposure
Cases of skin irritation and sensitization, local rashes or chemical burns can over time lead to skin allergy. Repeated or long term-inhalation of certain substances, causing respiratory irritation, could potentially lead to allergic asthma.
Anyone who is exposed to a high dose of a substance is inclined to form an allergy to that particular substance. Case studies have shown that workers subjected to repeated and prolonged exposure to certain substances also have a higher amount of allergy to those substances.
Allergies may also develop from repeated low-level exposure from chemicals in products. The products, or different products containing the same substances, may have been used for a long time, even for many years, before any reaction occurs. The usual case in this regard is with products that are applied to the skin which, over time, leads to skin sensitization issues. The release of the allergy may be delayed but once an allergy is developed it cannot be fully cured.
There are ways to reduce the sensibility, via for example immunotherapy, but the cure is basically to stay away from ingredients that trigger allergic reactions. This could be tricky as chemicals often have multiple applications. Some are used both as fragrance agents in cosmetics and as flavoring agents in food. Furthermore, exposure to the same chemicals in other settings, in for example surgery, may also trigger allergic reactions, thus causing wider issues.
If you get a reaction from using certain products or ingredients, go see a health care specialist to get a patch test. It is good for you to have the facts, and it is also good to add to the allergy statistics. Ask to also be tested for oxidized perfumes (read below if you want to know what they are!)
The most common type of allergy caused by cosmetics is contact allergy from the fragrances used in the products. But fragrances are not exclusively allergenic; there are also many preservatives that may cause allergic skin reactions. One common example is contact allergy caused by the preservative methylisothiazolinone (MI).
More on fragrances. Set aside that the fragrances often are allergenic in themselves, some fragrance chemicals become even more allergenic when they are in contact with air. Fragrance substances, such as citronellol that can be found in everything from toothpaste to shampoo, become highly allergenic when they are oxidizing; when they come in contact with oxygen in the air.
Researchers at Gothenburg University in Sweden have found that some fragrances become ten times more allergenic after exposure to oxygen. This is because hydroperoxides are formed by the oxidation and they are strong skin sensitizers. Only very small amounts of these hydroperoxides are needed to trigger allergy and eczema in a person that already is allergic.
The researchers found hydroperoxides already in samples taken directly from the manufacturer, but their tests also concluded that the hydroperoxides increased the older a product became.