Latex is a natural product that comes from a light milky fluid extracted from the rubber tree, Hevea brasiliensi. It's used in a wide variety of products, and it can cause allergic reactions in sensitive individuals. Despite the name, latex paint is made from synthetic ingredients and generally doesn't cause the same allergic reaction. However, some of its components might cause problems.
Natural rubber latex has been in use for more than a century. Latex paint became widely available in the 1950s. The world's rubber supplies had been used up during World War II and at the same time developers decided they needed a more durable polymer than natural latex for outdoor environments. This led to the development of synthetic latex paint.
Even though there isn't any natural rubber latex in latex paint, there are some known chemical sensitizers such as formaldehyde and ammonia compounds. Formaldehyde is a strong irritant used in pathology and embalming that can cause nasal tumors in rats. According to Latex Allergy News, it is possible that health care providers could be sensitized to formaldehyde in an occupational setting and have symptoms whenever they encounter latex paint.
The chemical components in formaldehyde can cause an immunoglobulin E, or IgE, allergic reaction. When this happens, your immune system identifies the formaldehyde as a harmful substance and triggers certain cells to produce IgE antibodies to fight the allergen. Formaldehyde allergies can occur either with direct contact or by inhaling formaldehyde particles or gas.
Your reaction to formaldehyde depends on the type of exposure. Formaldehyde gas or fumes released via paint might cause a burning sensation in your eyes, nose and throat, as well as skin rashes, tightness of the chest, wheezing, fatigue and headaches. Frequent or prolonged skin exposure can lead to allergic contact dermatitis, with itching and red, weepy skin.
To test for formaldehyde sensitivity, your doctor will take a detailed medical history and use a patch allergy test on your skin with a solution containing urea formaldehyde in petrolatum, melamine formaldehyde in petrolatum and other formaldehyde resins in petrolatum or isopropyl alcohol.
It's difficult to avoid all exposure to formaldehyde because it is normally present at low levels in both indoor and outdoor air and is one of the most widely used chemicals in products like paint and furniture. If you determine you have an allergy to this chemical and/or latex paint, you should use an oil-based paint instead. To treat any contact dermatitis symptoms, you might need topical corticosteroids, emollients or treatment of any secondary bacterial infection.
In rare cases, formaldehyde can cause a potentially life-threatening allergic reaction, called anaphylaxis. A report from Japan's Osaka Prefectural Medical Center for Respiratory and Allergic Diseases indicated that two dental patients developed a severe reaction after application of a formaldehyde-containing tooth filling. According to the journal Human and Experimental Toxicology, long-term environmental exposure to gaseous formaldehyde, such as might be in interior latex paint, promotes allergen-specific IgE-mediated immune responses.