The major source of natural rubber is derived from the latex, or milky sap, of the tree Hevea brasiliensis. Latex is a ubiquitous natural resource found in a variety of occupational and domestic commercial products. Latex hypersensitivity has become a significant medical concern in the last several decades among patients and healthcare providers. The apparent increased prevalence of latex allergy during the last few decades is due in part to the widespread use of latex gloves to prevent transmission of bloodborne pathogens such as human immunodeficiency virus (HIV). The frequent use of latex-containing materials within the healthcare system generates concern and anxiety in individuals with adverse reactions to latex. True latex allergy can cause serious complications, including death. This chapter will provide an overview of the epidemiology, pathogenesis, clinical manifestations, diagnosis, treatment, and prevention of latex of allergy.
EPIDEMIOLOGY AND PATHOPHYSIOLOGY
IgE-mediated allergic reactions to latex, while not common in the general population, are a leading cause of anaphylaxis in children, particularly during hospitalization. Life-threatening allergic reactions may be the presenting symptom in as many as 30% of latex-allergic children. The majority of latex-allergic individuals are highly atopic, with histories of allergic conditions such as rhinitis or asthma. Those at highest risk of having a latex hypersensitivity include healthcare workers, children with spina bifida and genitourinary abnormalities, and individuals with occupational exposure to latex. Latex allergy has been reported to be one of the top causes of perioperative anaphylaxis.
The prevalence of clinical latex allergy in the general population has not been established. In a study evaluating latex specific IgE in volunteers who were not clinically symptomatic to latex, the rate of sensitization to natural rubber latex was between 3% and 9.5% in the mid-1990s, but the prevalence of latex sensitization fell to less than 1% by 2006. Approximately 10% to 17% of healthcare workers are sensitized to latex. Children with spina bifida have the highest prevalence of latex sensitization, with reports ranging from 18% to 73%. Although these prevalence rates indicate the presence of latex-specific IgE by diagnostic testing rather than clinical allergic reactions, the high rate of sensitization and potential severity of reactions suggest that all patients with spina bifida should be evaluated for latex allergy prior to undergoing surgical procedures, to minimize complications as much as possible.
Most allergic reactions to latex occur with exposure to latex “dipped” products such as gloves or balloons. These products made from liquid latex rubber have a large number of soluble proteins capable of binding IgE. Currently, 15 principle latex allergens have been well characterized and are known to cause the IgE-mediated allergic reactions. The International Nomenclature Committee of Allergens in the International Union of Immunological Societies (IUIS) has labeled them Hev b 1-15. Specifically, latex allergens Hev b 1 and Hev b 3 are known to cause sensitization to natural rubber latex from direct mucosal exposure during surgery. ...