Latex Allergy

Background

Allergy to natural rubber latex is increasingly common and serious in children and adults. Latex is the milky fluid derived from the lactiferous cells of the rubber tree,Hevea brasiliensis. It is composed primarily of cis -1,4-polyisoprene, a benign organic polymer that confers most of the strength and elasticity of latex. It also contains a large variety of sugars, lipids, nucleic acids, and highly allergenic proteins.

More than 200 polypeptides have been isolated from latex. Latex proteins vary in their allergenic potential. Protein content varies with harvest location and manufacturing process. Basic knowledge of the manufacturing processes aids in understanding the medical problems related to latex exposure.^[1]

Freshly harvested latex from Malaysia, Indonesia, Thailand, and South America is treated with ammonia and other preservatives to prevent deterioration during transport to factories. Latex is treated with antioxidants and accelerators including thiurams, carbamates, and mercaptobenzothiazoles. It is then shaped into the desired object and vulcanized to produce disulfide cross-linking of latex molecules.

After being dried and rinsed to reduce proteins and impurities, the product frequently is dry-lubricated with cornstarch or talc powder. Powder particles rapidly adsorb residual latex proteins; other proteins remain in soluble form on the surface of finished products.

Latex is ubiquitous in modern society and particularly in health care. William Halstead first used latex surgical gloves in 1890. Latex has been used in a myriad of medical devices for decades. In the late 1980s, however, its use skyrocketed as latex gloves were widely recommended to prevent transmission of blood-borne pathogens, including the human immunodeficiency virus (HIV). Billions of pairs of medical gloves are imported to the United States in annually, often as powdered, nonsterile examination gloves.

In the 1980s and 1990s, heightened demand for latex to manufacture gloves and other objects resulted in hundreds of new, poorly regulated latex factories in tropical countries. The incidence of minor and serious allergic reactions to latex began to rise rapidly among patients and health care workers (HCWs).^{[2, 3, 4]} Latex sensitization can occur after skin or mucosal contact, after peritoneal contact during surgery, and possibly after inhalation of aerosolized particles with latex on their surfaces.