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 helps in understanding the medical problems related to latex exposure.
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. Latex has been used in a myriad of medical devices for decades. The incidence of minor and serious allergic reactions to latex began to rise rapidly among patients and health care workers. 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.
Three types of reactions can occur when using latex products:
Irritant Contact Dermatitis : This is the most common negative reaction to latex. Symptoms include dry, itchy, irritated skin—most often on the hands.
Allergic Contact Dermatitis (delayed hypersensitivity) : This skin reaction looks like the rash from contact with poison ivy and usually shows up 24–96 hours after contact.
Latex Allergy (immediate hypersensitivity) : This type of reaction usually happens within minutes of exposure, but symptoms can also show up a few hours later. Symptoms of a mild reaction are skin redness, hives, or itching. Symptoms of more serious reactions might include runny nose, sneezing, itchy eyes, scratchy throat, wheezing, coughing, or difficulty with breathing. Rarely, shock may occur, but a life-threatening reaction is seldom the first sign of sensitivity. A latex-exposed worker developing any serious allergic reactions should be taken to a doctor immediately.
What should employers do?
- Provide workers with non-latex gloves when there is little contact with infectious material.
- Consider the use of vinyl, nitrile, or polymer gloves appropriate for infectious materials.
- Provide reduced-protein, powder-free gloves, if latex gloves are selected for use with infectious materials.
- Provide training to workers on latex allergy.
- Promptly arrange a medical evaluation for workers with symptoms of latex allergy. Provide these employees with non-latex gloves.